I just completed the 'grounding mod'. Man, what a difference!

My WRX had a bad stumble or hesitation between 4 and 6,000 rpm even when fully warm. After adding several ground wires the stumble is gone!

I added 5, 12 gauge, THHN ground wires: one to each strut tower, one to each side of the intake, and one to the firewall. The last 3 are existing factory ground points. All 5 wires terminate at a two-piece solid copper lug on the neg. battery terminal. I used "Copper Shield" anti-oxidant on all connections. Also, I found that the factory ground at the firewall was done over painted metal (lame), so I cleaned that up.

I am amazed at the difference this mod made. I was skeptical but figured the cost was minimal and I had nothing to loose.

Okay -- I am skeptical. Where can I get detailed info about this?

I would like to know more also

http://www.i-club.com/forums/showth...threadid=141932

Also see the thread, "Stumble During Acceleration"

link does not work??

T.

Try this link:

http://i-club.com/forums/showthread.php?threadid=141932

donrgolf



user name
Us Texans actually do have a few tech posts!:p

Just did this mod yesterday as well. Holy S, what a difference!

Here is how we did it, and I will post pics soon.

2 gauge wire from Neg battery terminal to ground distributor block. 8 gauge wire from block to 5 separate ground points. Hesitation is gone, accel surges at low rpms, gone. And for those of you who follow my compaining, my EVC-4 is now functioning properly at all boost and RPM levels.

Entire cost of project, $40.
Time under the hood, 1-2 hours.

One of, if not the best mod I have ever done. Highly recommended, especially for those experiencing accel surges and bucking.

Good luck, speed safely.

Pete

And this works for ALL '02 WRXs, not just chipped cars, right?

Jorge (riftswrx) did this a few months ago as well. www.projectwrx.com has a writeup on it. I've never heard any bad things come from doing this mod to any level of car.

sajohnson,

As a electrically challenged person (ECP:) ), I am unfamiliar w/ the acronym THHN when refering to ground wires, could you please explain? Also unfamiliar w/ your 2 piece solid copper lug you mention. What did you use for ends at your contact points?

Sorry for all the questions, but an also experience a slight hesitation occasionaly and would like to end it.

Thanks in advacne,

Big Sky

THHN is the stiff, solid core wires used in home wiring. It's cheap, and can be had at most any home improvement store. Watch the jacketing on heat sources, it doesn't like heat. I have a 1000 foot spool in my car room as we speak :)

THHN = Thermoplastic High Heat Nylon

It refers to the insulation on the wire, which is spec'ed to 90 C. It's mostly used by builders and such.

Most silicone insulated welding wire is also spec'ed to 90 C.

there's probably a wide range of wire you can use...
I used 10 gauge primary (stranded) automotive wire and soldered and crimped ring connnectors

i did this mod today. i used 8 gauge audio wire crimped to terminal connectors. my mods are mbc, intake, and exhaust. i dind't notice much, i did experience though that it was easier to take off from a stop in 2nd gear and i can shift to fifth at 38mph or above and not get vibrations instead of 40mph and above. but the weather could have played a roll.

dennis

You wouldn't have noticed anything if you didn't have a problem to begin with. This is not a performance mod and you will not notice better starts. What you may have noticed is better performance due to resetting your ecu.

It only fixes a problem with a mild hesitation while accelerating throught 3-5K rpm.

If you are having problems with a slight jerk at 3-5K rpm do this mod. It works... fixed me anyway.


-Jonathan

The THHN I used is stranded and gas and oil resistant.

The insulation would be more important if we were running +12 volt supply wiring. From a safety standpoint since these are Neg. (-) ground wires, they could be bare. From a funtional standpoint though, bare wire might be problematic because any place the wire came in contact with metal would become a potential ground point.

one far out crazy question about this. they say if you get struck by lightning that it will ground out threw your rubber to the ground. is this going to help or hurt this cause? weird, wild, question just was thinkin bout this.........

Rubber is an insulator, the lightning will not ground out through the tires.

If lightning hits your car it will travel on the outside of the car's 'shell' of an metal enclosure.

Goodies learned from the Boston Museum of Science.

thanks PDG.....good good good.........

Well there's one less thing to worry about!;)

here is my story...

my car was "surging" a bit at low partial throttle in the 3-5K RPM range... I am not in this range very often without being near WOT, so I hardly ever noticed it, but every once in a while...

when I read about this "miracle mod", I went out and purposefully searched for the surging... after a bit, I found that I could produce it in a very repeatable manner... 3200 RPM, low throttle, mild acceleration - I would get a surging not unlike feathering the throttle...

I have done an ECU reset since noticing this issue, and it had no effect, so I decided to give this mod a shot and see what effect it had...

I didn't want to run 5 wires without knowing that I really needed to, so I started with a single 8gauge woven cable from a local stereo shop that I cut to length and crimped on eyelets... I connected this wire from the bolt through the negative ground cable on the battery, to the drivers side ground bolt on top of the manifold on the engine... I then went out for a test run... there was a noticeable improvement - the surging still there, but much more faint, almost imperceptible...

I then made a second cable and ran it from one of the passenger side strut top mount bolts to the passenger side manifold ground bolt... went for a second test run:

GONE!!! all traces of the surging gone, I worked really hard at trying to reproduce any surging, and could not under any condition...

I'm going to drive for a few more days and make sure I don't suffer any additional surges...

after that, I think I'll remove the wires and see if it comes back (tho I'm almost afraid to)...

just a bit more information for everyone to think about...

I do not have any better idea about what this does, other than good grounding is a good thing, but it made a marked improvement in my car...

Paul

Hey Paul
I had a similiar experience, but unfortunately and came back and went away again, and now its back. That leads me to believe that this is the way in which to fix the problem, now I have to just isolate exactly where the problem is stemming from pay special attention to grounding that. I will keep everyone up to date as this progresses.

Good luck
Pete

well maybe I won't "unground" for the sake of science... LOL

please keep me in mind when you do figure out what worked...

Whatever gauge wire you use and wherever you decide to add extra grounds make sure you use some type of conductive inhibitor. Try these links:

http://tnbsun4.tnb.com:8080/tnbcat/tnbcat/TELS_home_page_dsp.build_catalog_home_page

http://tnbsun4.tnb.com:8080/tnbcat/tnbcat/webcat_search_results_dsp2.build_part_home_page?p_ catalog_code=CKY&p_category_hier_id=CKY89&p_part_nbr=CP8&p_search_indic_flg=T

If they don't work, I used Thomas and Betts Kopr-Shield (P/N CP8-TB). Their site is

www.tnb.com

I can program computers, but am weak when it comes to good 'ol electricity :lol:

Just what do you mean by "conductive inhibitor?" Where do we use it?

Originally posted by sajohnson
Whatever gauge wire you use and wherever you decide to add extra grounds make sure you use some type of conductive inhibitor. Try these links:

http://tnbsun4.tnb.com:8080/tnbcat/tnbcat/TELS_home_page_dsp.build_catalog_home_page

http://tnbsun4.tnb.com:8080/tnbcat/tnbcat/webcat_search_results_dsp2.build_part_home_page?p_ catalog_code=CKY&p_category_hier_id=CKY89&p_part_nbr=CP8&p_search_indic_flg=T

If they don't work, I used Thomas and Betts Kopr-Shield (P/N CP8-TB). Their site is

www.tnb.com

We'd make a good team because it's all I can do to type this post! When I studied electronics in college, the latest processor was the 8088 and we wrote programs in machine language!

Inhibitor refers to oxidation inhibitor. I work for Metrorail in D.C. We use this stuff on any connections that are exposed to the elements or with dissimilar metals.

By conductive I mean that it contains copper, as opposed to straight silicone grease (although that would probably be OK).

Kopr-Shield contains:

Petroleum Oil
Copper
Clay
Alkylene Carbonate
Zinc Dithio Carbonate

It is just what I am familiar with. I'm sure there are other good products.

What is the explanation for why these extra ground wires eliminate the mid-RPM stumble?

edit: nevermind, read through the related threads

Noboby knows, it's magic!

Question, I have a front strut tower. If I run a cable to the drivers side, do I still have to run one to the passenger side?

Is Somber's way the easiest way to do it?

Leo

This is one example of why this board should be important to subaru. I hope some communication between the board and subaru comes along where subaru either thanks or congratulates the board for improving the design.

My hat is off to sajohnson for having come up with this fix. In retrospect, electircal grounding is one of the biggest contributors to poor performance

Originally posted by thng
This is one example of why this board should be important to subaru. I hope some communication between the board and subaru comes along where subaru either thanks or congratulates the board for improving the design.

My hat is off to sajohnson for having come up with this fix. In retrospect, electircal grounding is one of the biggest contributors to poor performance


Actual, Subaru should be aware of it. This fix is nothing new, they've been doing it on B4s in Japan. I remember first seeing pictures of an install about 6 months ago, or more. I may mention it to someone at SOA if I remember next time I get the chance, but they, like most manufacturers, probably won't do much. It's a common problem in a lot of cars, although I will admit the WRX has it worse than any other car I've been in.

Luckily, it's a cheap easy fix.

Originally posted by Leonardo
Question, I have a front strut tower. If I run a cable to the drivers side, do I still have to run one to the passenger side?

Is Somber's way the easiest way to do it?

Leo



I only grounded my intake manifold, and it fixed the problem, so you shouldn't need to do both strut towers. I'm not done toying around, I'm going to try a few more wires, and then filtering any noise out of + line, but just running the intake manifold to a bracket by the battery, then to the battery solved all my noticable problems.

I was under the impression that the only wire you run on the passenger side is a jumper from the tower to the intake (both on passenger side.)

The reason I bring this out is because I was recently of the thought that it didn't matter where you run your grounds and more is better...

I jumped to the passenger strut tower, drivers strut tower and intake on the drivers side. After this I had a hesitation worse than before. I removed the lead off the battery that went to the passenger side and it went away. Now I only have a jump to the drivers side intake and the drivers side strut tower and things feel good.

Anyway.. I'm not sure if there was a problem with that particular ground or if you shouldn't run a wire off the battery directly to the passenger side tower but that was my experiance...

-Jonathan

I've noticed a slight shutter or stumble at between 2800 and 3K RPM in 5th gear on the freeway...thats pretty much the only time I feel it...continues through almost 3500 rpm's ..
Turbo back
Rampod
EBC
BOV
Does this sound like a possible ground Mod fix ??

Don't know until you try. It's cheap enough that it's worth it to find out.

Most people have reported that this mod will cure that type of prob. I did it and it did almost eliminate all stumbles. Just have to reground my boost controller and Ill be all good.

Pete

Originally posted by mynew02
I was under the impression that the only wire you run on the passenger side is a jumper from the tower to the intake (both on passenger side.)

The reason I bring this out is because I was recently of the thought that it didn't matter where you run your grounds and more is better...

I jumped to the passenger strut tower, drivers strut tower and intake on the drivers side. After this I had a hesitation worse than before. I removed the lead off the battery that went to the passenger side and it went away. Now I only have a jump to the drivers side intake and the drivers side strut tower and things feel good.

Anyway.. I'm not sure if there was a problem with that particular ground or if you shouldn't run a wire off the battery directly to the passenger side tower but that was my experiance...

-Jonathan

When you say jumper from the tower to the intake, that's incorrect. You want the negative terminal on the battery to be your central grounding point. My guess is one of the problems with the stock system is they daisy-chain grounds together like that. You want to add wires, and for the best signal, you want each one to have one end on the negative terminal of the battery, or very close to it. You don't want to add as many grounds as possible, either, because that can cause other issues. I would start simple. Add a ground, test drive, add another, test drive, etc. As soon as the hesitation is gone, leave it alone. If you find later that you can feel it, just not as much, add another wire.

Like I said earlier, I only have 3 wires in my car. One from the negative terminal right to the chassis, where I have a bracket mounted. One to the left side of the intake from that bracket, one to the right side of the intake from that bracket. I could take the bracket out of the equation and run them both straight to the negative terminal, I just chose to do it this way, because it's a little neater, but not necessarily any better.

FWIW I did the mod a few days ago using 8 gauge wire, and can honestly say there is no perceptable difference in the car. I've been running the Stage 0 since X-mas, and honestly nothing changed by doing this. The only thing I can actually measure is my wallet is a bit lighter. Seriously though, don't get me wrong. You really can't over ground a car, and it is for that reason why I am just leaving it as it is, but honestly on my wagon nothing changed. Perhaps this is only a sporratic problem with some WRX's. Who knows... Just another POV from someone who has done it.

--Matt:)

Obsidian: How smooth was your car before the mod ? If you didnt have any hesitation probs before then there was nothing to fix ! ?

I have some hesitation in the 3-5k area and will be doing this mod soon.

BTW I think Jorge aka RiftsWRX was one of the first (if not THE first) to do this mod .. Kudos to him.

Yeah, it should be noted somewhere this doesn't ADD anything, it's not getting you more power, it's not speeding up acceleration, it's smoothing out an existing problem. If you're car runs smoothly, it probably won't do a thing. If your car doesn't run smoothly, and it still doesn't work, make sure you post all the details.

Are 8 Ground points really neccessary?

I did it and it fixed my stumbling.

Come to think of it, the grounds for the exhaust sensors should also be looked at unless the sensors are internally grounded...

Off topic:

I just acquired a 95 Saturn that I will use for commuting. My sube is just getting abused :D .

But it needs an AC system...

Ted

Can one of you that have done this mod, please post some pix. thanks. my car has had this problem since day one.

Ok, there have been 4 threads about the Grounding Mods so far in this week.

I'm making one thread and sticking it so please, don't do another thread untill you go throug this one!

Thanks!
Leo

Ooops, me bad!

I didn't remember closing the tread.

Leo

After doing this I am very surprised at how different the car acts. The engine is definatly quieter and smoother, that 5000 rpm jerkeyness is completly gone. I bought 25 feet of 8 guage wire, 5 brass ring terminals from a stereo shop, and the 0 guage battery terminal from napa. Cost me about $20 (im friends with the owner or the stereo shop he gave me everything at cost). I connected the ring terminals to the same spots as listed previously in this thread and connected all of the ends to the napa battery terminal, was a very tight fit, I crammed them all in there as neatly as possible and bolted the thing down. I was going to solder everything down to make it look neater but was too cold outside for my 45 watt soldering iron to heat up enough to melt solder. I will try and get some pics later this afternoon if anyone wants.

I just did it today:

I ran two 4 gauge Monster cabling ground wires with gold ring terminals from the negative battery to the strut tower, and then from the negative battery terminal to the intake manifold ground...

Voila! No more jerkiness, power delivery is smooth in all gears...

I must say the mod was very worthwhile and was easy...

I may add a few more grounds to be safe (I have extra cable), but hey, it's fixed now, so if it ain't broke, don't fix it!

I should have pics up soon...

Ok here's my pics. Sorry some of them may be kinda fuzzy, was gettin dark and had to use low light boost on camera...

Intake

Battery terminal

Another view

this is pointless

so here is an interesting thing I noticed but need to verify more. after this mod I don't get the clutch shudder that much any more. anyone else notice this?

I was wondering this myself. I do not have as many of the clutch problems that I use to have, the shudder is a lot less noticeable now. Coincidence?

A small note to anyone thinking about this mod...

As a ham radio operator (callsign KB1GWQ), I have a lot of radio equipment and other electronics in my WRX. When the ignition is in the ON position, before the engine even begins running, many of the engine electronics, motors, pumps, and other items cause a huge amount of RFI (radio frequency interference), especially noticeable in CB and 10m amateur bands (~30MHz). When the car is running, injector noise and various other annoyances will significantly raise your noise floor and cause reduced receive distance.

I plan on grounding out my intake manifold and other parts today after work, and I'll let you know how it goes. With my meters and radios, I can give some pretty quantitative data on how much noise this alleviates.

I'll keep you posted.

/Andrew

Originally posted by Kha0S
A small note to anyone thinking about this mod...

As a ham radio operator (callsign KB1GWQ), I have a lot of radio equipment and other electronics in my WRX. When the ignition is in the ON position, before the engine even begins running, many of the engine electronics, motors, pumps, and other items cause a huge amount of RFI (radio frequency interference), especially noticeable in CB and 10m amateur bands (~30MHz). When the car is running, injector noise and various other annoyances will significantly raise your noise floor and cause reduced receive distance.

I plan on grounding out my intake manifold and other parts today after work, and I'll let you know how it goes. With my meters and radios, I can give some pretty quantitative data on how much noise this alleviates.

I'll keep you posted.

/Andrew


I dont know what it is about this car but it is really susceptible to radio interference. I have a power inverter that I use to plug things like my cell phone and laptop into etc, and whenever I have my cell phone plugged in every radio station comes through with nothing but static!

Originally posted by BOP
For the record: I used to get serious hesitation issues at almost any throttle position between 2700 and 3100 rpm, it almost felt like the engine was misfiring. I did this mod last Friday and after several days of driving around, I can say that it took care of 90% of my hesitation problems. Now I get only a *very* slight hesitation at 40% to 50% throttle in that RPM range. I grounded the intake manifold first, and I'm pretty sure that it made all the difference, because I couldn't really feel any improvement after I added 3 more runs to the firewall and both strut towers.

Just my 2 cents.


This is EXACTLY my findings.... I thought that my problem stemmed from the ECUs fuel map. Since I have had this strange but, VERY noticeable, stumble pretty much anytime I am at 1/2 throttle and then lay into it.
I thought that it was a mapping problem, because I hadnt noticed this problem until I put my greddy Profec-A in. So I guess that I figured that the fuel map wasnt set up to see boost as quickly as the EBC would allow it to build. --- I guess that it made sense at the time, but I was never really happy with that being the probable cause.

Fast-forward to today......
I have been driving with the grounding mod for a couple days now, and the hesitation is still slightly noticeable, but not as "bucking-bronco" as it was before.
I guess that I will try a few more to see if I can get it to go away entirely.

So to anyone who hasnt done this mod, DO IT... you might not see any improvement, but you might solve problems that you didnt even know that you had.... and it only costs a few bucks in comparison to what you might spend on other mods....

yk

i am going to do this mod too!!

however, just for argument sake, can someone use a multimeter to see if the new ground cable actually carries any current?

i am no EE but as far as reasoning goes, should the ground be carrying negative charge?

and can someone explain "over grounding"

Personally i am just going to add 2 maybe 3 ground tops (negative to strut tower / manifold to strut / manifold to intake fender bolt) because i don't see the point of running 6 ground in addition to the existing one

theoratically, these ground would be working as long as the engine is running, so we should see some kind of current when the car is stationary? I know the "interfereace" occur most prominently at 3k to 5k or so (which coincide with the turbo spooling?)

btw, shouldn't we reground the ECU also??

Just curious .......wondering if cars with the hesitation problem are first or second allocation cars.

Barry

Originally posted by Barry
Just curious .......wondering if cars with the hesitation problem are first or second allocation cars.

Barry

interesting.... mine is a first allocation.

Originally posted by TerenceT
i am going to do this mod too!!

however, just for argument sake, can someone use a multimeter to see if the new ground cable actually carries any current?

i am no EE but as far as reasoning goes, should the ground be carrying negative charge?

and can someone explain "over grounding"

Personally i am just going to add 2 maybe 3 ground tops (negative to strut tower / manifold to strut / manifold to intake fender bolt) because i don't see the point of running 6 ground in addition to the existing one

theoratically, these ground would be working as long as the engine is running, so we should see some kind of current when the car is stationary? I know the "interfereace" occur most prominently at 3k to 5k or so (which coincide with the turbo spooling?)

btw, shouldn't we reground the ECU also??


Technically, all current is "negative charge". You're just measuring the flow of electrons, which are all negative. A volt is the number of a electrons passed a point in a second (6.25 quintillion, or something, learned that number almost 10 years ago and don't remember it), an amp has to do with the number of these points in parallel. They're all flowing from negative to positive. The reason we view circuits as have positive voltages and a ground is just for math. It's a lot easier that way.

As for measuring things, you can grab a multimeter and measure stuff, but it may or may not tell you anything useful. The only useful thing I picked up from it was that the alternator generates some serious interference on the wire grounded to the passenger side of the intake manifold, and it's variable with RPM. Haven't tried to fix it yet, though. A scope is much better for this kind of thing, but I don't have an extension cord long enough to get it to my car.

"Over grounding" is when you daisy-chain grounds everywhere in an attempt to tie every point together. You want to pick a central point and use that. In this case, you want that to be the negative terminal on the battery, so when you ground yours, don't do it "(negative to strut tower / manifold to strut / manifold to intake fender bolt)". I ran the negative to a bracket on the fender right by the battery, then to each side of the intake manifold. Problem solved. I added one to the firewall, no noticable difference. You definitely don't want to do negative to strut, strut to manifold, manifold to intake fender. If you choose to do those three points, run a wire from each one back to the negative terminal of the battery.

Regrounding the ECU might also help. I've got a Unichip on the way, and when I have the ECU out for that, I'm going to take a look at those grounds and see how they are.

this is pointless

BOP- Check build date in door jam on drivers side...........

this is pointless

Originally posted by Narcisse91

The only useful thing I picked up from it was that the alternator generates some serious interference on the wire grounded to the passenger side of the intake manifold, and it's variable with RPM. Haven't tried to fix it yet, though.

Possible solution is to use 2 unshielded wires and twist them tightly around each other and then put a shieled casing around them. By having two wires next to each other like that the two electrical fields around each wire will cancel each other out along with any additional electrical fields that are present. That is the theory behind twisted pair CAT 5 wire anyways. ;)

I agree with BOP....I ran about 1 1/2 ft of 4 gauge to my intake manifold and it fixed about 90% of my problem.

this is pointless

BOP - I have a wagon (1st allocation) with MT. There is a grounding wire to the firewall behind and below the IC. I'll check later to see where it leads. :)

Originally posted by BOP

It's 09/01

End of my theory................;)

Can somebody trace a wire for me?

I've seen on other wrx's there is a ground wire bolted to the rear engine mount, on the firewall just behind and below the intercooler (looks just like all the other 18-ish AWG ground wires on the car) - My car is missing this ground wire.

Would somebody please trace this wire and tell me where it comes from? Thanks

:)

It goes into this dark void somewhere in the engine compartment.. Ausin.. I think someone else in one of the other grounding MOD threads answered this for you.

The only info I got was that it "looks like it goes down by the tranny"... I'm still looking for a little more info, like where it originates/what component of mine is not currently grounded.

..... to whoever first came up with this great mod. I felt an incredible difference in the overall driveability of the car. No more stutter in first gear , no more hicups while winding the car out. I admit Iwas skeptical, but with so many people speakin highly of this I had to try it, and I am glad I did it made a very pleasureable difference.


Zman

For anyone with a couple extra minutes of time, make note of your gas milage and throw it up here. If the car is running smoother, it might be running more efficiently, therefore, more mpg. I'm just curious, it may not be anything noticable, but who knows, maybe we'll pick up a mpg or two.

Before doing this mod I was filling up my tank every other day. Now it is every 4th day. But I also reset my ECU so that may have had something to do with it.

My gas mileage is the same before and after.

Guys, the wire behind the intercooler right above the upper rear engine support on the firewall (not on the engine) is the ground wire for the items listed below. The wire on the engine under the intercooler is connected directly to the negative battery terminal.

- power window main switch
- rearview mirror heater (driver side)
- cruise control module
- power window relay
- rear 12V accessory relay
- short connector (security)
- keyless entry control module
- clutch switch (MT)
- key lock Solenoid (AT)
- integrated module.

REF: 2002 Model Year Wiring System Section 7, Page WI-22, WI-138

this is pointless

Yes Alex, thanks. Saves me a trip under the car. ;)

Ditto - Thank you very much Alex!

no problem guys!:)

I've been doing some research on this grounding mod. I believe I have figured out part of the reason why the ground is so poor on our Subaru. The reason being, One, there is only one ground wire connecting the engine to the battery. Two, this engine ground wire run parallel with a high current positive wire. This has 2 effects. It can cancel out the magnetic field if equal and opposite currant is run on both sides. Or, it creates an internal resistance for the side that has less current running trough because the magnetic field induced an opposite charge into the wire. In essence, the ground wire on the Impreza is ineffective and should be rerun completely on a different route.

I'm currently designing a new system. I've been doing test on 3 different wrx for about 4 weeks. All added only two wires to connect the two ground points on the manifold to the battery. So far, I've got mixed result. The following is what I've found.

Car A:
with complete turbo back exhaust, up pipe and unichip, did not notice any difference in performance and fuel consumption.

Car B:
only drop-in K&N filter, notice engine smoother across entire RPM range, no change on fuel consumption.

Car C:
stock, notice different at 3-4500 RPM, car burns more fuel, when from over 250 miles per tank to less than 210 miles per tank.

I believe there are other effects with this grounding mod. I need an OBD tool so I could scan all the sensors and see what is really happening. Do you guys know where I can find a good one?

PS: maybe Subaru should pay me for this research on solving the engine ground wire problem, so I can have some $$$ to modify my car... :rolleyes:

Alex L, When you did this, did you unhook the negative to the battery? If so how long, this will determine if you reset the ECU or not.

Did car A,B or C have any hesitation problems to begin with? Interesting that you lost mpg in car c. I fall under car B and agree with you that it smoother across the powerband. Also agree with you that there are other benefits. Things that I have noticed:

Almost eliminated the cold clutch shudder (it's happened once and that was very little), when letting off the gas and getting on the gas lightly (no more jerkiness). You said that that the ground behind the IC is for clutch switch (MT), do you or someone else know what this is?

en3d, all 3 cars had been reset after the installation. I can't tell you if those 3 cars had hesitation problems because they are not my own cars. The results are all responds I got from the owner. I strongly believe that car C did not have any problem to begin with. The owner have had another WRX before which had got stolen. He told me his new car runs much better than the last one (before the installation of the grounding mod).

The clutch switch is part of the starter system. It triggers the starter interlock relay when you depress the clutch, which will allow you to start the engine.

I've been following this post for awhile and decided to finally try it. My car did not have any hesitation prior to mod. Using #10 wire, I ran a ground from neg. battery terminal to intake manifold. Took it for a ride. Dramatic difference in smoothness and off/on throttle response thru the entire rpm range. BTW,I did not reset the ECU. I guess my car would fall into Alex's "B" group. I think I will leave well enough alone for now and just use 1 wire. Many thanks to you folks for finding this mod.


Barry

I had a slight hesitation before doing this mod but figured that it was cheap enough that I might as well try it. Seems as though this made the problem worse. Also, I noticed a decrease in MPG. Does anyone think that an ECU reset would help? If so how do I go about doing it?

Thanks,
Todd

Originally posted by wrxtasy555
I had a slight hesitation before doing this mod but figured that it was cheap enough that I might as well try it. Seems as though this made the problem worse. Also, I noticed a decrease in MPG. Does anyone think that an ECU reset would help? If so how do I go about doing it?

Thanks,
Todd

Yes, try resetting the ECU. Park the car somewhere let it get cold, overnight would be best otherwise leave it for 3 or 4 hours. Disconnect the negative terminal and leave it off for about an hour. Connect the terminal and turn the car on, let the car idle until it gets up to its normal operating temp. Take the car for a drive and drive it how you will normall by driving it. If you will be racing it do a buncha sprints if you will be driving it on the street just drive around your town a bit. Spend about 20 - 30 minutes driving around. And then you're all set.

i did this mod atleast a month ago with great results,BUT....L/KM is way down.i found a japanese( the originators of this mod) site that compares the effect of different ground points on fuel economy ,power delivery,etc......apparently some points do effect fuel economy by as much as 1litre per 10kilometres:eek:
anyway....i am changing my ground points today and will see what happens.
if it works ill post the recommended points,if not ill go bury myself in a hole:)

Originally posted by Kha0S
A small note to anyone thinking about this mod...

As a ham radio operator (callsign KB1GWQ), I have a lot of radio equipment and other electronics in my WRX. When the ignition is in the ON position, before the engine even begins running, many of the engine electronics, motors, pumps, and other items cause a huge amount of RFI (radio frequency interference), especially noticeable in CB and 10m amateur bands (~30MHz). When the car is running, injector noise and various other annoyances will significantly raise your noise floor and cause reduced receive distance.

/Andrew

I am working on the 2003 Crown Vic's (cop cars), and I've noticed that for the police package the plant grounds EVERYTHING. The hood, trunklid, transmission, exhaust, frame, lots of stuff(not all to the battery, but between parts). These are extra straps that they add to the police cars to deal with all the interference from the extra stuff (radio, lights, etc.) they add in. I was talking to an electrical engineer on the prorgam, and he said they have 11 extra grounds on that package. He thought they could do about the same performance with about five, but the police like to have the straps.
With that said, they don't do any of it for the regular cars, or the Marauder(I'll have to check on that), although these aren't really highly tuned engines.

I have driven my new, 2002, Impreza TS wagon for just over 100 KM and have noticed the following problems:

1)rough idle until warmed up;
2)hesitation when first accelerating from a stop or while moving.

Is this behavior normal until break-in or is this car a candidate for the grounding solution or, worse, is it a lemon?

You new car shouldn't behave that way. I would check with the dealer before any DIY remedies. The ECU should be set properly when you take delivery of the vehicle. However, if you have disconnected the battery - it will take some time to relearn your parameters.

When you say rough idle, are you referring to a general shaking while idling, or something engine related, like constantly varying RPMs? Subarus don't like being cold, and shaking while idling is characteristic of most of them. That's been my experience, anyway, and the experience of everyone I've talked to when it comes up.

More info on the hesitation when you hit the gas would be good.



This mod has nothing to do with how the ECU is set, this has to do with poor wiring, btw.

My car has always had a jerky acceleration. For example, if I was cruising steady in 3rd and let off the gas, the moment I stepped on the gas lightly, my car would shudder slightly. The best way I can describe the symptoms is that they made my car feel jerky and unsmooth when letting off the gas, and then on.

Anyways, I just added a single 8-guage audio power wire with two crimped on ring terminals from the neg-battery terminal to the intake manifold bolt(driver side).

I took the car for a ride this morning, and it feels smoother. I usually get clutch shudder before the car warms up, but I didn't notice it this morning. Maybe it never was clutch shudder after all?

Since I am happy with the results from my single wire, I'm not going to bother with anymore. I don't think it's my imagination that my car feels smoother....it really helped.

I used 10gauge wire and ran 5 wires all terminating at the negative battery post as recommended. I have a Unichip among other mods and I did notice an improvement though for me the problem has not completely gone as I had hoped. Would using heavier gauge wire really make any difference?

Ed

I tried the negative to 1). wall, 2). intake/driver & 3). intake/passenger...I cannot hear my turbo spool as loud, it feels like I have my stock intake & exhaust back on and I get herky-jerky when trying to snail along in traffic in 1st & 2nd gears! Did I just get the REVERSE results? :confused: :lol:

I have added more grounds as well and gotten WORSE than stock results. I would go with the single ground and add only if you need to. It is possible to ground to the wrong spots and get worse results...

I put this on this weekend, and I swear my car is smoother, especially in the low rpm range. I'll have to wring it out this week, se if it feels any smoother when flogging it.

I know "RiftsWRX" had a write up about this a while back and it had a lot of info in it if anyone cares.

one more testimonial: i did this mod this weekend, reset the ecu, and i do feel like the car accelerates a lot smoother. for the wires i bought black battery cables from an auto parts store, that already had connectors crimped on, and it looks really clean. i got one 19" and one 24", and it cost about $5 total. it took about 15 minutes to do the whole thing. just do it, it's worth it.

Originally posted by mynew02
I have added more grounds as well and gotten WORSE than stock results. I would go with the single ground and add only if you need to. It is possible to ground to the wrong spots and get worse results...


i have a background in electronics and i can't see how this is possible unless you messed something else up while adding the wires. or maybe you connected the ground to the positive terminal of the battery. D'OH! then i guarantee you'd have worse performance.

I didn't think it was possible either. I figured the more grounds the better, but it seems as my problem has gotten worse also. There was a huge difference in MPG after this mod and hesitation was much worse right after. I have been driving with the mod for about a week and it seems to more subdued now (ECU re-learning?). I am going to take off some of the new grounding points today to see if that makes a difference.

Todd

Originally posted by wrxtasy555
I didn't think it was possible either. I figured the more grounds the better, but it seems as my problem has gotten worse also. There was a huge difference in MPG after this mod and hesitation was much worse right after. I have been driving with the mod for about a week and it seems to more subdued now (ECU re-learning?). I am going to take off some of the new grounding points today to see if that makes a difference.

Todd


well, that is amazing. i'm sorry, man.

sucks to be me I guess

Todd- Try the negative terminal-intake manifold cable only. Seems to be the successful combo.

Barry

Wasn't there a grounding kit that someone sold?

I believe about 1 year ago we were talking about grounding and most people didn't believe it actually did anything.

There was someone who had a website w/ the grounding kit installed and everything.

we need to do a poll to vote whether the
1. mod works,
2. doesn't work, or
3. don't want to try it.

seems to work great for me.

It definitely works, no need for a poll, but everyone needs to remember:

1) It doesn't add anything, only fixes an existing problem. If you don't have that problem, it won't do anything for you.

2) You CAN overground. I've explained this a few times, but I still see people adding 5 or 6 wires in there right away. Add one, if that doesn't help, add a second, etc.

Originally posted by pio!pio!
Wasn't there a grounding kit that someone sold?

Looking through my latest issue of Sport Compact, I saw a grounding kit by a company called 'arospeed' Comes in a bunch of different colors too. But this assumes you're going to ground more than one point. You may (and probably) only need one (to the manifold). But thought I'd through that in there in case anyone is looking else is looking for it also.

Originally posted by pio!pio!
Wasn't there a grounding kit that someone sold?



who wants to buy, i'll sell you a "kit", if you are in LA, i'll install it for you too

3 wires, 6 eyelat , how much you wanna pay?


Narcisse91, ...thanks for the explanation, couple pages back, i still think ppl should reset the ecu and someday, ground the ecu tho.
I did 3 wires ground and car seems smoother, i was so surprise when my g/f AND 13 yrs old bro in the back seat felt that too!

Found what I was talking about :D

http://www.lumine.net/subaru/legacyb4/tuning/earthing1.html
http://www.lumine.net/subaru/legacyb4/tuning/earthing2.html

Although this is for the B4 RSK, when the topic came up, no one really believed it worked

I did this mod this weekend, and although I haven't had much chance to really test it, it does seem to have removed the slight hesitation that I had around the 3K mark.

I added just a single ground wire to the intake bolt on the passenger side.

For those of you gettin worse performance after the mod, it sounds like you need to let the computer re-learn your driving habits again.

I added one wire from the ground battery terminal bolt to the driver side manifold ground bolt. No more hesitation. I thought surely people were just feeling the placebo effect, but nope.

There's no need to go from the battery to each bolt on the manifold. Just choose one. The manifold itself is solid aluminum and conducts much better than any wire could. Unless I start feeling hesitation again I'm going to leave my mod as is (about one foot of wire). The next logical addition would be from the passenger side manifold bolt to the passenger strut tower.

-George

Originally posted by George71
I added one wire from the ground battery terminal bolt to the driver side manifold ground bolt. No more hesitation. I thought surely people were just feeling the placebo effect, but nope.

There's no need to go from the battery to each bolt on the manifold. Just choose one. ...

I added the first wire (battery negative terminal to intake grounding strap) and, like others, about 90% of the problem is gone. Wow, what an easy fix. My WRX seemed to hesitate in second gear more, or maybe due to the torque/gearing relationship in that gear it was more noticable, but anyway the pulsing that was felt is gone.

I decided, what the heck? and tried it.

I am embarassed to say that I used SPEAKER WIRE that I had lying around the house.:eek: (I'll replace it when I get around to finding something better!)

One wire to the strut closest to the battery, one to the manifold, and one to the nut closest to the battery that holds in the radiator.

WOW!:eek:

The car is much smoother. The hestiation seems to be completely gone.

BUT!

It's so smooth that it doesn't feel as fast anymore. I think the hesitation added a raw feeling that made the car FEEL faster.

BTW, I did NOT reset the ECU.

One more vote to give this a try. Worked for me!

Originally posted by pio!pio!
Found what I was talking about :D

http://www.lumine.net/subaru/legacyb4/tuning/earthing1.html
http://www.lumine.net/subaru/legacyb4/tuning/earthing2.html

Although this is for the B4 RSK, when the topic came up, no one really believed it worked

<cough>

Paul Hansen

Originally posted by NiceguyOnSubySt
I tried the negative to 1). wall, 2). intake/driver & 3). intake/passenger...I cannot hear my turbo spool as loud, it feels like I have my stock intake & exhaust back on and I get herky-jerky when trying to snail along in traffic in 1st & 2nd gears! Did I just get the REVERSE results? :confused: :lol:

Since he's too embarrased to post I'll tell you guys that he has since let the ECU "relearn" and his car is running great! Says it's a worthwhile mod for the cost...which for him was $0. :rolleyes:

Originally posted by shirokuma


<cough>

Paul Hansen

????:confused:

quote:
--------------------------------------------------------------------------------
Originally posted by shirokuma


<cough>

Paul Hansen
--------------------------------------------------------------------------------



????

look what he drives.

To follow up on my own post:

As I said below, I had three ground points. The car ran much smoother, but didn't seem to have the spunk it used to. After a day of driving, I got fed up with the total loss of edgey character in the acceleration and decided to try reducing the number of grounds.

The result is that I now only have the manifold grounded, the car runs smoothly, does not stumble, but still has the WRX edgey whoosh of acceleration when I want it.

To summarize, my experience says to only ground the manifold and you'll fix the stumble problem. Grounding more may actually rob the car of some of its performance.

HTH.

Originally posted by kurichan
I decided, what the heck? and tried it.

I am embarassed to say that I used SPEAKER WIRE that I had lying around the house.:eek: (I'll replace it when I get around to finding something better!)

One wire to the strut closest to the battery, one to the manifold, and one to the nut closest to the battery that holds in the radiator.

WOW!:eek:

The car is much smoother. The hestiation seems to be completely gone.

BUT!

It's so smooth that it doesn't feel as fast anymore. I think the hesitation added a raw feeling that made the car FEEL faster.

BTW, I did NOT reset the ECU.

One more vote to give this a try. Worked for me!

YEAH BABY!!!! My 3500-4000 Hesiattion is gone!

2000 2.5RS here and this was the best money I have spent on my car yet!

Thank you whover brought this idea back to light on the club.

For exactly what I did look in Normaly Aspirated forum.

Cleaned factory painted grounds and added 3 12guage runs.

Cheers,

_chris

Just did the single point driver side manifold ground and ECU reset. Car is A LOT smoother. In the lower gears and RPMs the car was very jerky. Now it has totally disappeared and it is a smooth as silk. Not sure about the radio quality going up, still seems pretty bad. :) Another satisfied customer.

I may try this mod...

My car is stock, but even so I can tell that there are a couple brief spots in first gear where the car hesitates ever so slightly. Not much, but enough to be annoying. I'm sure that as I add more power this little hesitation thing may become a bit more pronounced.

This is a common modification that the FC RX-7 guys do with their injectors to kill the beloved 3800 RPM stumble that occurs when the secondary injectors come online.

Did the ground mod today with 10ga wire to the core support and strut bolt...

Definitely smoother and pulls harder throughout the powerband.

Another thumb's up!!!

For $5,you can't go wrong...;)

Ok, just completed the grounding mod. Just did one wire to the intake manifold though. Not sure if I reset the ECU though. All the electronics were reset except the clock.
Does that mean the reserves werent drained enough to reset the ecu?

Thanks
PS, havent noticed much difference either

When I did mine, I only had the negative disconnected for a few seconds, and the clock was the ONLY thing that reset. It takes a while for the ECU to reset, though, so you're probably ok.

Thanks
But are there any signs that will indicate whether or not the ECU has been reset?
I had the negative disconnected for about 15 min, and I pressed on the brake pedals for a few seconds as well.

Didn't do the grounding mod but hooked up my avc-r finally.

Stumbling in acceleration is totally gone.

So seems it probably has something to do with the factory boost controller... maybe it's not getting enough juice? Does anyone here have a boost gauge? If so, I'd be interested in knowing what your boost is doing while you're stumbling.

Of course.. this wouldn't explain why people with NA cars seem to feel a difference as well... oh well I tried.

Originally posted by KwanDDS
Thanks
But are there any signs that will indicate whether or not the ECU has been reset?
I had the negative disconnected for about 15 min, and I pressed on the brake pedals for a few seconds as well.

There is no indication. You may not have left the batter disconnected for long enough thou. I have been told to leave it for an hour.

Originally posted by kurichan
To follow up on my own post:

As I said below, I had three ground points. The car ran much smoother, but didn't seem to have the spunk it used to. After a day of driving, I got fed up with the total loss of edgey character in the acceleration and decided to try reducing the number of grounds.

The result is that I now only have the manifold grounded, the car runs smoothly, does not stumble, but still has the WRX edgey whoosh of acceleration when I want it.

To summarize, my experience says to only ground the manifold and you'll fix the stumble problem. Grounding more may actually rob the car of some of its performance.

HTH.



I also tried 3 connect points...experiencing same smooth running and loss of "edge"...also, getting rediculously good gas mileage! :lol: I've been trying to use up my gas so I can run at autox with a lighter tank...damn, the gas lasts sooo long now!:rolleyes:

I also ran a ground between the manifold and the negative terminal of the battery, an 18 inch, #4 AWG, prefab starter cable I bought for $6. Canadian ($4 U.S.). It reduced but did not eliminate the hesitation. I will be installing another ground to one of the driver side strut bolts to find out if there is further improvement.

I used a stainless steel bolt, flat washer and spring washer but I think it might cause galvanic corrosion. What type of material is the hardware you used to ground to the manifold?

Has anyone tried just cleaning and verifing the factory gounds? Sounds to me like everyone is feeling better results from the ecu reset and think its the extra wires.

Don - there are several people who posted success with this mod without an ECU reset, and I went thru my process pretty methodically to try to eliminate your concerns (as I posted earlier)...

1. tried an ECU reset - hesitation no better...
2. checked factory grounds, seemed ok, reconnect - no better...
3. ran 1 wire from battery ground strap to drivers side of intake - hesitation - better but not gone...
4. ran 2nd wire from passenger strut tower bolt to passenger side of the intake - hesitation eliminated (or so slight, no longer an issue)...

I still am not sure why this is having the effect it is - all I know is good grounding/earthing is good for electrical systems - and in my particular case - added grounding seems to have eliminated a problem with my car...

my wrx was pretty bad with the surging and hesitating. i did the mod and it went away. i used black 8 gauge monster audio cable, on both sides of intake, passenger strut top and bolt behind intercooler. i ran them to a small, unfused lightning audio distribution block. threw away the plastic part. i ran 4 gauge to the neg batt terminal. i put tape, scothkote and heatshrink around the block and zip-tied it to the cable in front of the battery. the whole thing is very stealth and well done. it wasn't cheap though. i spent about $60 on the whole rig.

! wire to intake manifold from negative post hesitation almost all gone. Huge improvement.:D

1 piece of 4 guage from the batt to the grounding point on the intake manifold fixed it for me. :D Quick and easy. :)

-John

Originally posted by mad-dog999
1 piece of 4 guage from the batt to the grounding point on the intake manifold fixed it for me. :D Quick and easy. :)


I actually did this last nite. I was amazed that it worked. I may add one more since there is still a slight hesitation.

Where exactly is the contact point for the Ground cable on the Throttle body? Is it on the driver side, toward the front where there are 2 ground cables already?

Thats the intake manifold. Thats where I ran my one wire to and it really helped get rid of the hesitation alot.

Originally posted by hkwan
Where exactly is the contact point for the Ground cable on the Throttle body? Is it on the driver side, toward the front where there are 2 ground cables already?


I ran mine here: http://home.cfl.rr.com/eskram/pics/wrx%20wagon/4%5b1%5d.jpg

Originally posted by hkwan
Where exactly is the contact point for the Ground cable on the Throttle body? Is it on the driver side, toward the front where there are 2 ground cables already?

The pic above shows the point on the driver's side, there's one on the other side in the exact same spot. It's actually the intake manifold. :)

-John

I did this mod a while back and grounded the drivers side shock tower, the bolt on the intake manifold (drivers side), and ran a wire from the passenger side grounding bolt (near the airbox) to the passenger side intake manifold. It helped a little but I felt it could be smoother.
So a few days ago, I finally ran an additional line to the grounding point behind the IC and my car now accelerates noticably smoother!

Did a single point to the intake manifold and it worked like a dream, BUT...

The hesitation came back yesterday...

Will keep you updated.

After doing the mod, I reset the ECU for a second time doing something else, and noticed some of hestitation/flutter came back. The difference this time was that I did not take the time to reset the ECU in the 100% correct manor. I basically just plugged power back up, and then right away rev'd up and down for a minute. So be careful to reset your ECU correctly, this will definitely make a difference (and makes sense too if you think about it for a second). Plug power back up, let idle for a while (without rev'ing), shut off wait a bit, then take for a drive the way you normally drive it (daily driver or street). The fully instructions are out there.

I have had the GND mod for a month or so. The hesitation comes and goes still. No real change. Although I re-did the GNDs on my Legacy and 323GTX and they both turn over quicker at startup but both run the same as usual. My 13 year old 323GTX runs, idles, and accellerates smoother than the WRX. Oh well, its just one of those Sube' quirks.
Later,
Greg D.

Originally posted by gpd323
Oh well, its just one of those Sube' quirks.Maybe if you brought the wrx out to an autox every now and then instead of giving all your love to the 323, the wrx would run better for you;) :lol:

Ok I've been experimenting with my grounds this past week since I just took the 1,100 mile trip from Long Island to Florida. Noticed a few things. First of all, I had three grounds: one from the passenger strut to the passenger intake manifold, second from the negative battery terminal to the drivers intake manifold, third from the negative battery terminal to the bolt behind the intercooler. Hesitation has dissapeared about 95%. Also I have a TurboXS stage 1 unichip.
Here's what I noticed: I got between 310-320
miles per tank (averaged 65 mph). Filling up at a little below 1/4 tank (using about 13 gallons). After getting here i took off the ground from the negative terminal to behind the IC and intake ground (passenger side). Leaving only the passenger ground to the passenger strut tower. Took a 300 mile trip to a relatives house here (65mph) I only got 260miles on that tank (13 gallons).Car felt dogish, but that could be the 80 degree weather. Replaced only the drivers side intake ground back to the negative terminal and mileage goes back up (320 per tank, bolt behind IC still disconnected and cars is smooth)!
Now the wire from neg. terminal to behind the IC is disconnected and the car still pulls smoothly. Gas mileage is higher now as well. Hopefully, this is not all in my head. I tried my best to drive the same (granny driving) and from what i can tell the grounds do have some affect on gas mileage. Has anyone else tried to log gas mileage differences and come up with different conclusions. I'm guessing from my simple experiments that one could probably try a whole different bunch of grounding combinations and come up with different conclusions (ie- better gas mileage, performance). Maybe I just have too much time on my hands! :lol:

Anthony

Just adding to the collection of experiences for those interested. I have a stock MY02 WRX that I bought 3000 mi. ago. I did notice slight stumbles at times.

I ran a single ground from the battery to the intake ground boss and there is a noticeable difference. The stumble is definitely gone. It seems smoother overall, but that may be my imagination.

I had a hard time believing it works, until I did it. :D

Originally posted by braub
I ran a single ground from the battery to the intake ground boss and there is a noticeable difference. The stumble is definitely gone. It seems smoother overall, but that may be my imagination.

Also for those interested, I didn't disconnect the battery, so the ECU was not reset.

Is everyone using the same method for connecting the terminals to the wires? I guess everyone is crimping...and I am wondering if the quality of crimp is affecting the end result.

Who is soldering the terminals and does anyong think that the method makes a difference (positive or negative)?

Did regrounding the ecu have an effect?

Has anyone tried grounding the exhaust pipe only? (near the O2 sensor - which ever one)

The wire of choice is 4 ga?

Going to try and do this ground project this weekend. Plan of attack is:

Negative terminal to manifold (driver side).

Right strut tower mount to right side manifold.

Uninsulated ground strap from second flange after turbo to body.

All terminals will be soldered.

Then we'll see what happens....

Ted

If I were you, I would read through the thread.

You'll see that not too many people used 4 gauge, most used a smaller cable.

You'll see why grounding from the strut tower to the manifold isn't as good as straight to the negative terminal.

You'll see everybody's responses as to their own experiences resetting the ECU.

All grounds should go directly to the negative terminal of the battery otherwise you may introduce ground loops with circulating currents consequently worsening any electrical problem. Properly done soldering is best - make sure that there are no cold solder joints. Crimping is fine as long as the crimp is as tight as possible (gas tight). With either method of attaching wires to terminals, it is important that all of the wire strands are not nicked when the insulation is stripped off and the strands are making thorough contact with each other and the connector. Put some shrink-wrap tubing over the wire and terminal where the wire enters the terminal (slide the shrink-wrap over the wire before you put the wire into the terminal then, after you solder/compress the connection, slide it over the connection and heat to shrink). I used #4 AWG starter cable which has prefab ring connectors and is precut to specific lengths and don't cost much. I have two supplementary grounds; one to the manifold on the driver's side, the other to a strut bolt on the driver's side. There was some improvement in hesitation with the one to the manifold. There is a lot of improvement since I added the one to the strut bolt.


Originally posted by thng
Is everyone using the same method for connecting the terminals to the wires? I guess everyone is crimping...and I am wondering if the quality of crimp is affecting the end result.

Who is soldering the terminals and does anyong think that the method makes a difference (positive or negative)?

Did regrounding the ecu have an effect?

Has anyone tried grounding the exhaust pipe only? (near the O2 sensor - which ever one)

The wire of choice is 4 ga?

Going to try and do this ground project this weekend. Plan of attack is:

Negative terminal to manifold (driver side).

Right strut tower mount to right side manifold.

Uninsulated ground strap from second flange after turbo to body.

All terminals will be soldered.

Then we'll see what happens....

Ted

I've watched what others have done so far and have decided to do the following: 1 run of 6 gauge from the passenger side manifold to the battery first -- crimped 12mm X 10mm ring terminals. Check for residual hesitation. Then place a second cable to the driver's side shock tower, if needed.

I just returned from a visit to Charlotte's Auto Fair today. I got a chance to test my first run's effectiveness during the trip. Great reduction with the manifold run. I'll check the shock tower run's effectiveness next weekend to see if it gets any better.

Originally posted by Narcisse91
If I were you, I would read through the thread.

You'll see that not too many people used 4 gauge, most used a smaller cable.

You'll see why grounding from the strut tower to the manifold isn't as good as straight to the negative terminal.

You'll see everybody's responses as to their own experiences resetting the ECU.

Sorry, I deleted a portion of my post....

I did read the thread and found that there was really nothing consistent. The conclusions I drew were:

Most ground mods worked and there were some that didn't. Why did some not work?

There were several mentions of 4 ga wire used where the outcome was always positive. Those that did not indicate wire size both had good and bad results. But, those that did use 4 ga wire did have a positive outcome.

I know there nothing better than grounding to the battery but there is a point where, because of so much wire at the terminal, you can't get to the terminal (looks like a rat's nest) and, from past experience, the appearance of corrosion on the terminal.

The grounding of the ecu also did not seem to have any consistent results either. But there was also question on whether there were any other systems present (ie. piggy back electronics, etc).

The trend did show that the mod is likely to have a positive effect and that carefully chosen ground points make the difference between a good mod and a bad one.

Out of curiosity, I looked at a couple of Hondas and Toyotas and discovered the abundant use of small guage wire to ground but they were just all over the place: trans to body, trans to block, exhaust pipe to body, head to body (small wire), block to body (heavy wire).

It just fed my initial conclusion that there was such a big rush on the part of Subaru to get the car out to the public as soon as they completed 95% of the development for the US market.

Ted

I used 12 gauge copper stereo wire.

Ran it from the negative terminal on the battery to the drivers side intake manifold and from the negative terminal to the drivers side strut tower bolt.

I ran the wire under the existing wires so you'd never notice it unless you looked.

The car pulls soo much smoother its hard to believe. All the time I just thought it was because of the first short gear and it was caused by engine braking.

I did mine in a similar manner. I used 12 ga. but for good measure I doubled up and ran two wires together, since I didn't have anything heavier. Just did the manifold-to-battery, soldered and heat-shrunk the terminals. At first glance it looks stock.
I have the factory gauge pod with the voltmeter, and before adding the ground the voltmeter would generally read about 15 volts with the engine cold and gradually drop to around 13 once hot. After the mod it does not drop below 14.

As I stated in a previous post to this forum, I ran auxillary #4 AWG grounds which has greatly improved the hesitation/stumbling problem.

I am certain that, due to inadequate electrics (especially the alternator and battery) and wiring, engine and accessory performance is suffering. My new Impreza TS has electrical problems since I took possession of it 3 weeks ago. The initial tipoff was the varying heater fan speed with engine speed. I hooked up a digital voltmeter to the auxillary power outlet and discovered that the voltage dropped to as low as 11.9 volts when the car was in park with the air conditioning on. Although they are not certain about what the problem is, Subaru is replacing the alternator. I also suspect the integrity of the factory installed grounds and the wire size used, especially the one to the alternator (I hope there is a ground wire and the ground is not through the housing and bolts to the engine). It is unfortunate that Subaru doesn't take more care with their cars' electrical systems. After-purchase problems which could have been prevented don't help their reputation.

Automaton, I hope you realise that I have NEVER seen a alt that wasn't grounded through the motor.

Plus I don't know if subaru changed, but the motor use to be the primary grounding point for the whole car.

Originally posted by XT6Wagon
Automaton, I hope you realise that I have NEVER seen a alt that wasn't grounded through the motor.

Plus I don't know if subaru changed, but the motor use to be the primary grounding point for the whole car.

Unless the engine has taken the battery's job as DC supply, the negative terminal of the battery is the primary grounding point for the whole car.

I hadn't noticed anything odd, but I thought I might as well clean up the paint on the fender for ground coming from the battery. What could it hurt and it only takes 10 minutes, right?

I have the factory pod w/ voltage gauge. I used to swing 12-13 volts on idle and just higher than 14 while cruising. I always thought that was due to my UR underdrive pulley, but I was wrong. After the paint scrape, I am a solid 14, even at low idle.


Another new behavior is my Eaglite HID kit (from the midnight moose GP) are on all the time now! As I recall, a few people complained about the "DRL" coming back on, even after doing the DRL mod. They installed a resistor to prevent this. Most people, like me, didn't see this behavior. I chalked it up to weird wiring and didn't think about it because my lights workd the way I wanted them to.

If you didn't install a resistor kit and don't have "DRL" try cleaning up your grounds and see if the lights come on for you.

I haven't tried driving hard or above 3K RPM, so I don't have info on performance. However, I am convinced that the ground sucked, so I am going to run a couple wires from neg terminal to strut tower and intake manifold -- just for good measure.


Finally, I can drive my rear view mirrors w/ my Nextel i85 phone. That is truly weird.



Dan

Duh, of course, but OFF the battery the end negative battery cable is the "primary" point. My fords all bolted that to the body somewhere near the battery. My old subarus all bolt the negative battery cable to the tranny through one of the engine to tranny bolts.

Just as I figured, poor factory installed grounds. Your 12-13 volts at idle is similar to my car's experience. I will be scraping the paint under the factory installed grounds and see what improves.


Originally posted by Sophocles
I hadn't noticed anything odd, but I thought I might as well clean up the paint on the fender for ground coming from the battery. What could it hurt and it only takes 10 minutes, right?

I have the factory pod w/ voltage gauge. I used to swing 12-13 volts on idle and just higher than 14 while cruising. I always thought that was due to my UR underdrive pulley, but I was wrong. After the paint scrape, I am a solid 14, even at low idle.


Another new behavior is my Eaglite HID kit (from the midnight moose GP) are on all the time now! As I recall, a few people complained about the "DRL" coming back on, even after doing the DRL mod. They installed a resistor to prevent this. Most people, like me, didn't see this behavior. I chalked it up to weird wiring and didn't think about it because my lights workd the way I wanted them to.

If you didn't install a resistor kit and don't have "DRL" try cleaning up your grounds and see if the lights come on for you.

I haven't tried driving hard or above 3K RPM, so I don't have info on performance. However, I am convinced that the ground sucked, so I am going to run a couple wires from neg terminal to strut tower and intake manifold -- just for good measure.


Finally, I can drive my rear view mirrors w/ my Nextel i85 phone. That is truly weird.



Dan

I noticed something while I was putting in my single run (for now) of 4 gauge wire yesterday. There seems to be a coating over the stock ground wire connections that run to the fender well and to the firewall. Is this lacquer to keep the screws from turning off or is it some kind of conductivity enhancer? Just wonderin'.

I think it is just to keep the moisture from getting at the connection and possibly to keep it from getting loose.

Okay I'm spinning in circles,

Now I've tried this mod several different ways. I keep changing because I keep reading what is good and what could be bad. Right now I'm running:

Setup A
1. negative battery -----> driver's intake
2. negative battery -----> passenger strut
Conclusion: Still hesitation, fixed at first, but now it's about 80% hesitation free.

I did run:

Setup B
1. negative battery -----> driver's intake
2. passenger strut ------> passenger intake
Conclusion: about 98% hesitation free
Can someone tell me why this way is bad when it basically cured my hesitation problems? Car ran great (gas mileage up as well)!

My mods are:
TurboXS Unichip setup for:
K&N filter
Samco IC hoses
Running 16psi boost

I have no idea why not going directly to the negative terminal of the battery gave more improvement. Rewire the grounds as they were when the hesitation was most reduced; if it's better, keep it that way. Let us know what you observe.

Originally posted by Justbordn22
Okay I'm spinning in circles,

Now I've tried this mod several different ways. I keep changing because I keep reading what is good and what could be bad. Right now I'm running:

Setup A
1. negative battery -----> driver's intake
2. negative battery -----> passenger strut
Conclusion: Still hesitation, fixed at first, but now it's about 80% hesitation free.

I did run:

Setup B
1. negative battery -----> driver's intake
2. passenger strut ------> passenger intake
Conclusion: about 98% hesitation free
Can someone tell me why this way is bad when it basically cured my hesitation problems? Car ran great (gas mileage up as well)!

My mods are:
TurboXS Unichip setup for:
K&N filter
Samco IC hoses
Running 16psi boost

Has anyone recorded turbo boost when hesitation happens? Mine will happen under 1/2 throttle in 2nd gear . RPM's are about 3,200 to 3,500. Boost is approaching 14 psi.
If I accelerate gradual or go WOT, I NEVER get the hesitation. I'm just wondering if there is a slight detonation due to almost full boost and only half throttle. Perhaps the ECU is doing it's job and retarding the ignition timing? Do any of you guys have symptoms similar to mine? Are you guys actually feeling hesitation with little boost?

Thanks, Skoob

I don't have a turbo, I have the normally aspirated Impreza TS. Hesitation with my car consitently occurs around 2,000 RPM. Like your car, if I gradually accelerate, there is virtually no hesitation/stumbling. After adding 2 grounds, the problem is almost gone. This makes me think that regardless of turbo or not, the problem is a combination of things, including grounds, which are common.



Originally posted by skoobahead
Has anyone recorded turbo boost when hesitation happens? Mine will happen under 1/2 throttle in 2nd gear . RPM's are about 3,200 to 3,500. Boost is approaching 14 psi.
If I accelerate gradual or go WOT, I NEVER get the hesitation. I'm just wondering if there is a slight detonation due to almost full boost and only half throttle. Perhaps the ECU is doing it's job and retarding the ignition timing? Do any of you guys have symptoms similar to mine? Are you guys actually feeling hesitation with little boost?

Thanks, Skoob

I just did this mod. I am running six points right now. One to each strut, one to each side of the intake runner, one to the rear of the engine, and the last one from the battery to the firewall. I am using blue coated 8 gauge wire from Cartoys. I wasn't sure if it would help, but thought that it couldn't harm anything. I noticed a much smoother ride. I use to experience a slight hesitation around 3500 rpms. It is no longer there. I think that I would recommend this cheap mod. What can it hurt! Cheap and didn't take very long.

Todd
:D

This hesitation problem and its simple remedy is cheap, didn't take very long and is effective if a person knows about this fix. The hesitation problem must be costing Subaru a bundle in warranty service. I don't understand why Subaru can't fix this problem for everyone by improving the electrical system and ensuring that the grounds are properly installed on bare metal.



Originally posted by Ronin2121
I just did this mod. I am running six points right now. One to each strut, one to each side of the intake runner, one to the rear of the engine, and the last one from the battery to the firewall. I am using blue coated 8 gauge wire from Cartoys. I wasn't sure if it would help, but thought that it couldn't harm anything. I noticed a much smoother ride. I use to experience a slight hesitation around 3500 rpms. It is no longer there. I think that I would recommend this cheap mod. What can it hurt! Cheap and didn't take very long.

Todd
:D

Any thoughts about the idea of skoobahead posted above? Is this possible?

i just removed 4 of the five ground wires and it now pulls harder,and generally feels better:confused:

skoobahead.....are you using a mbc???how accurate is your boost guage???

Which ground connection did you leave?

Originally posted by okamikatekore
i just removed 4 of the five ground wires and it now pulls harder,and generally feels better:confused:

skoobahead.....are you using a mbc???how accurate is your boost guage???

Yep I'm using the Dawes MBC with the bleed drilled to 1.5MM. My boost is set to 15.5 PSI. Like I said earlier, no hesitation unless high boost and 1/2 throttle(which is actually hard to duplicate unless trying since I have the bleed enlarged) Sure sounds like the ECU is retarding at that point. Noone else has posted their boost when hesitaion occurs. Anyone?

Skoobahead

I haven't noticed what my boost is doing when my engine stumbles. I don't have any mods though. Is this ECU thing still possible? I'll try to check out my boost gauge next time I notice the problem.

Rumple,

If you are running totally stock then you will not get that much boost at 1/2 throttle. If you have stumble then high boost is not your reason. Unless your running 87 octane which I'm sure your not.

Skoobahead

Cool:cool:

No I'm not running 87 Octane. I guess the grounding mod might help me then.

Thanks. I'll write back with results.

Well, I ran the wire from the negative terminal to the driver-side manifold bolt last night and went for a spin. It definately idled and ran smoother and was a lot easier to engage the clutch smoothly and the "bucking" was gone! The hesitation is still slightly there, but like other's have posted it seems like it cured about 90% of the hesitation problems. I might try running another wire this weekend to see if I can get that number up to 100%. The car is much more of a pleasure to drive. Thanks to whoever found out this trick! Any idea what Subaru does for a fix to these problems?

Nothing!

Originally posted by Paulie V
Well, I ran the wire from the negative terminal to the driver-side manifold bolt last night and went for a spin. It definately idled and ran smoother and was a lot easier to engage the clutch smoothly and the "bucking" was gone! The hesitation is still slightly there, but like other's have posted it seems like it cured about 90% of the hesitation problems. I might try running another wire this weekend to see if I can get that number up to 100%. The car is much more of a pleasure to drive. Thanks to whoever found out this trick! Any idea what Subaru does for a fix to these problems?

Excelllent! That's good to hear!:rolleyes:

I tried the originally suggested 5 or 6 ground points and noticed some improvement but not much. BTW, I was using 8gauge wire.
Then I got some fat 2gauge stuff and ran about 18inches from the negative terminal directly to the manifold on the drivers side. Then took about 24inches of 4gauge from negative terminal to drivers side strut mount. Problem gone about 80% now. I still get some bucking under half throttle or less. If I mash the pedal to the carpet no hesitation. Go figure.

Ed

Automaton:
Which ground connection did you leave?

the front left intake manifold ground remains(8guage audio w/gold terminals)

I have the TurboXS stage 1 Unichip and had several different grounds on my WRX. I've tried almost every variation, but days later the surging/hesitation comes back. I recently did the TPS threshold mod on my Unichip (22kohm resistor in parallel with R8) and found that I no longer need the grounds. The car runs much stronger with the grounds removed! In my own opinion I think that our boost solenoid (spelling is probably wrong there) may be what causes the surging. I notice that if I am running part throttle and .05mpa my car surges or hesitates, but if I'm below that the engine drives smooth. Weird! In any case I'm sure this mod may help smoothness on a stock WRx, but I feel this may be more of a boost issue. Just my opinion please don't flame me lol :D Anyone else with unichip and hesitation should really try the TPS mod. It worked for me and eliminated some high EGT's at part throttle.

Ant

Justbordn22,

I have to agree. For those that have solved their hesitation that's great, but mine really seems to be related to excessive boost at part throttle. Just seems like the ECU is doing it's job and retarding the timing under these conditions. Gradual throttle or WOT no hesitation. Maybe I'll put my stock BC back on and test the difference.

Skoob

ok, here are a couple of potentially stupid questions regarding the grounding mod.

when attaching the grounds to the manifold and/or strut tower bolts, do these bolts need to be torqued down or just hand tightened?

is taking the strut tower bolt off going to cause any problems with the strut? (i.e. cause it to be misaligned)

is it necessary to reset the ECU after adding the necessary number of new wires?

is this something the dealer should take care of under warranty?

i want to try this mod because the hiccups during moderate acceleration are starting to drive me bats. i also want to do it right and not cause any potential problems.

thanks in advance for any input
Dave

this is pointless

so I did the grounding mod, and YES.. it is great!!! awesome.. it made the car smoother and the stock stereo sound better (or I am imaging it)

here are my findings,

I started by adding 3 wires, with ring connectors
1.) passenger side manifold bolt --> negative terminal
2.) driver side manifold bolt --> negative terminal
3.) passanger side strut --> negative terminal

I noticed a great improvement, car is smoother, runs great, very nice feeling, though still a little notchy, but just enough, the stereo (I have upgraded oem speakers and subwoofer) sounds better, but slightly noticible, but better...

then, I added the 4th wire, to the bolt on the firewall below the IC,

I then get all these surges and bucking when reving, but still it was better than without grounding, the engine was super smooth
and the stereo sounds awesome! at volume level 5 the car was already booming... it was nice...., but I was less impressed by the drivability of the car (with 4 wires)

so today, I unhooked the wire going to the strut tower, and it seems like it is more drivable without surges. but the stereo doesn't sound as good (i.e. not as clean)

so I am going to drive around for the next couple days switching between having 3 or 4 wires to see which on is better..

FWIW:

I have noticed that the stumble/hesitiation is intermittent. I have not touched my original installation so I am wondering what else might be causing the rough acceleration.

What about different types of fuel? I always run 93 octane, but I fill up at a variety of stations--name brand and generic. This tank full is Sunoco and it seems to be running smoothly. I know there are variations in additives and that there are multiple 'blends' depending on season and geographic area.

The mod did definitely make a difference (same gas before and after) but At least in my case the problem hasn't completely gone away.

For those who have tried the grounding mod. and had no improvement. (I am one)

I have had the same stumbling on my car, I tried turning down the boost (MBC), no luck.
I tried the grounding mod, no luck

REMOVED THE MBC (cheap one offered with Vishnu kit), no stumbling or hesitation! Just smooooooth with stock boost control. (although less power of course).

I think the Vishnu stuff is of high quality, but IMHO the extra money for a good quality boost controller is worth every penny.
I am now opting for the Unichip boost control, and am getting a local tuner to tune my Unichip for it.

Oh, almost forgot, the MBC stuck open a few weeks ago (couldn't get above 6 or 7 PSI), I glad that it didn't stick in the closed position!

Hope this helps.

I think the grounding mod probably works best with bone stock applications. I'm seeing comments on here about Unichip and ground mod with little or no improvement (mine too) and am steering more towards boost control. Although it may be an expensive fix I'm curious if anyone with a Unichip and a AVC-R or SBC-ID have any hesitation or stumbling. I'm guessing this will cure the disease in a matter of speaking. As of now the grounds are removed and the car runs the same.

Just my $.02

Ant

I'll try removing the grounds one by one, to see if it makes any difference

this is pointless

Perhaps because you have a Stage 2 kit you are getting boost much more quickly (Turbo Back exhaust) your ECU is getting confused as to whether or not to increase or decrease timing. That's why I say the TPS Threshold mod will fix this problem. I'm not saying that anyone who has this ground mod is just imagining things, just that for me and Stage 1, this mod has really shown me no increase or decrease in stumble/hesitation. It might show improvement for some and none for others. Who am I to say what happens to who's car. Therefore, at the end of my comment I put:

Just my $.02 :rolleyes:

I'm no electrical engineer, but I drive my car everyday. When I put the ground wires on the car is great for a day or sometimes a week. MY GUESS is....that this is simply a boost/timing problem.

Ant

Canuck and Justbordn22,

I agree. I really think this hesitation is related to the ECU retarding the timing under high boost/part throttle. Fo