My settup.
EJ20G, TDo5, STi 550's, Flipped Intake Manifold, TBE, Intake

Im having some weird issues with my car. When the car is 90% to reaching normal runing temps it runs fine with no issues. However when it reaches normal temps(water at 85C and oil at 85-90C) it has a bad hesitation from 4K-5.5k. I thought that my AF's or timing was off, but when i put it on the dyno my AF's where 11.5:1 and my knock didnt get above 35.
After doing some logs i found out that at 4K my Load would fluctuate from 8000-8500 about every 1/2 sec. Making a log looking more like a roller coster then a log :(. Right when i would hit about 1bar of boost it instantly would drop it down to .8 then back up to 1 and so forth. The boost fluctuation would be consistant with my Load fluctuation and so forth. Looked at my ignition and fuel points in the trouble area and they where perfectly fine.
I then proseded to put my Stock ECU back in, and i didnt have any of those issues as long as i kept the car from hitting fuel cut.
Also my batt. voltage drops down to 13.1V when above 4K RPM.

Any help would be appretiated.

Thanks
Kirill


Problem Solution: Replaced spark plugs with stock heat range NGK-R Coppers gapped at .025 and fixed the problem.

first off my car also drops voltage under WOT about 13.4v, dont know if thats normal with g motors or what. Just letting you know I have experienced teh same thing.

From what your saying it would have to be something related to ING vs water temp. Make sure your timing isnt being retarded with coolant temps. Whos doing your tunning? Also might want to check injector lag with the new injectors since your rocking the 550cc and not the stockies. Also due the usual check plugs, maf, and vacume lines aka boost leak or intake leak.

Interesting.............

I just got my motor running again this morning with the new shortblock. It sounds like it does the same thing your does with the power fc. Runs fine with the z4 ecu and hesitates badly with the power fc in that rpm range, also has a lumpy idle compared to the z4 ecu. I added some timing and it got better but it is not right at all.

will the power fc pull timing based on knock?

kevin how did your raiils turn out there was a kid from MN that asked me to do a set of G rails from him.. you intersted?

will the power fc pull timing based on knock?


I don't think it will. I don't think it is a "learning computer".


Check your plugs. Mine went bad and caused a bad miss at around 5000 rpm. I checked them when I was pulling them out and the spark was pretty weak. Maybe when it is under heavy load/boost the fuel is drowning the spark out?

I put in some new NGK irridiums and it runs great again.

my Ign vs. Water temp is set 80C-110C and 8Deg of timing to be pulled by 110C. However i changed the value from 8deg. to 3 deg and it did the same thing.
And my inj lag is nothing abnormal. The weirdest thing is this. My friend Noah has a settup very similar to myne. Same Inj, and the only thing that is different is that he has a 2.5 shortblock where myne is a 2.0L. He hits 1.4 bar with no problems at all, where im having a hard time running .9 bar. We are both using the same generic map, and with my old settup TMIC &440's i never had this issue. However with FMIC and 550s i do.:confused:

And when i plug in my stock 3b ECU i dont have any problems that i have w/ the PFC. I can go WOT, partial throttle, and everything. I can hit 1bar of boost as long as i stay away from fuel car, where as w/ the PFC i cant even get close to 1bar with out it starting to cut power.

Im doing all the tuning myself so its a steep learning curve, but there is no local PFC tuners in my area.

As far as spark plugs go, i changed them out about 2months ago with 1stage colder NGK's gapped at 28.

I also unpluged my MAP senseor thinking that it was crapping out, however that didnt change anything except run lower boosts.


Jaxx, the powerFC doesnt have a learning feature built in. But thats what you get with 13yr old technology.

On a side note, i found out that you can use the stock boost control solenoid to controll boost via PFC. All that needs to be done is have the Boost Controler function turned on in the PFC and set it to the apropriate boost setting in the Boost control window. The only down side is that you cant run more then 1bar with out the PFC throwing a CEL.

Im doing all the tuning myself so its a steep learning curve, but there is no local PFC tuners in my area.

As far as spark plugs go, i changed them out about 2months ago with 1stage colder NGK's gapped at 28.


There is a local guy here (Vegas) that has experience with the powerFC if you are interested.


Try gapping them smaller - I use 0.025 on my ej20g

i am not talking about learnig to knock threashold but retard on knock

my tec will do this

i am not talking about learnig to knock threashold but retard on knock

my tec will do this

Im 99% sure the power-fc wont control that. On the other hand hows your fuel pressure. Do you have a leaking injector? I would still pull your plugs and check them. On a side note are you using the commander to tune or datalogit. Cause we had a situation where while using the datalogit some one missed a file in the software and had similiar problems to what you are experiencing. and yes gap at .28-.25 BKR7E ngks.

oh and when I had a fmic and 550's on my ej20g dan at got speed used my stock boost solenoid and tuned the car to 17.5psi using power-fc

Jaxx, I ran out of time to get the fuel rails and fmic on so I am just going to wait till spring and do it when it's warmer out. I was able to build a bracket out of thick aluminum sheet and with a washer holds the fuel rail down nicely and no need to weld :) I would make a couple more but don't know for sure if it will truly work as I never ran them, I don't see why it wouldn't though.


So my hesitation is consistent with the z4 ecu as well and extra bad with the power fc, plus my idle sucks with the power fc. I don't know wtf is going on with it. I am curious if there is a way to reset the power fc back to the original map provided by Apexi. Atleast this way I can be 100% the problem is not ecu related. Maybe some stupid switch is on or some mundane detail is off with both snowman's and my power fc. The strange thing is I can't get the idle to smooth out regardless of playing with tuning.

power-fc and idle dont mix like two dic's

cold weather could do that to yea too.

my 5000 foot observation
there is no reason to have a knock sensor if it dosn't pull timing in a det situation

to me a knock count of 35 is high
the spot your talking about is extreamly knock prone
try adding .2-.3 afrs of fuel and pull some timing
i am all the way down to 6 deg of advance at 5k rpm

To smooth out my idle I had to add some advance in the low rpm. I used to have some problems but found one line disconnected to a pcv and then advanced the ign in low range.


"initialize" is the way to reset pfc to factory settings. If you're going to use a pfc you should look into the dataloggit since it is easier to tune with and has its own support yahoo group to get these kind of answers from others that use the same set ecu.

Im using the datalogit to tune, the comander is by far the worst tuning tool EVER.
The thing that i dont get is why does it run fine on the stock Ej20G ecu(ment for a tdo4, TMIC, 440's). And when i had my old settup my car had none of these problems(except i had high knock).

And from 4K-5.5K my timing is between 18-21degrees.

Hey kirill its BJ, long time no see. Anyways, I was having this exact same problem (mods and engine are not the same I know but this helped my car). My car was hesitating very heavily around 4000 rpms and I couldn't figure out why. I even did a bunch of data logs and something was clearly off. I had switched to colder plugs in the summer which ran fine until the colder weather hit and then I started to get this problem. Maybe I'm way off base here but maybe try and switch back to the stock heat range of plugs and see if that helps. I read somewhere that the cold weather and the colder plugs can cause a similar issue even though at your power level you should be using the colder plugs. Just a thought. Oh and I saw those pictures you posted of your car. Sounds like a mean machine.

Some info.
Put the stock ECU back in and got a chance to drive around a bit. Boost is set to .8bar but will go up to 1bar in high gears. And it started doing the SAME THING:furious: .
So im going to go back to the stock heat range iridium NGK's and see if anything changes. What do you guys thing about .25gap?

I run 0.025" gap (I think thats what you meant) on my ej20g and it got rid of consistent bogging/misfire in the 5-6K range with WOT. Mid 90s Audi S4 cars run the same gap if you want to run iridiums instead of coppers.

So at this point im ready to set my car on fire!
Double checked all my IC piping clams, Intake manifold bolts, all the pipes and peases that have anything to do w/ the air entering the motor and they where all fine. Put on a new MAF thinking that my old one was crapping out. Checked the resistance of my coils when the car was hot thinking that they might be going out(got the burn marks to show for it also). Turned the O2 sensor off w/ the powerFC thinking that it might be going out. Checked my TPS sensor, and it was good.
AND IT IS STILL DOING THE SAME THING :mad:
The only thing i got left to do is put in some new plugs and gap them down. If that doesnt work i dont have a clue on what it might be.
I also noticed that i can go about 80-90% throttle running .9 bar and not do the hesitation, but the second i go WOT it starts doing the same thing! Anyone got any ideas?
I think that if the plugs dont change anything, im going to take off my intake manifold and rewire my engine harness. :(

I had a Power FC on a nissan and had hesitation do to a bad coil pack, so it could be your plugs since you checked everything else. I also had boost oscilation at one point when it was coolder, but it was because the wastegate duty was set to high.

Good Luck.

IS your ECU MAF based? What is your MAF hitting?
Sometimes, and sometimes not, the ECU will FREAK when it maxes out. This will lead to wacky fuel injector durations, which of course will lead to awful performance.

Personally, I am an NA 1990 ECU, which of course doesnt like boost. But..... a friend can't run more than 12-14 boost on an SS ECU because his ECU maxes out and does EXACTLY what mine does.

Somehow measure the MAF signal. IF you see more than 4.8, you need a bigger flowing maf.....

IS your ECU MAF based? What is your MAF hitting?
Sometimes, and sometimes not, the ECU will FREAK when it maxes out. This will lead to wacky fuel injector durations, which of course will lead to awful performance.

Personally, I am an NA 1990 ECU, which of course doesnt like boost. But..... a friend can't run more than 12-14 boost on an SS ECU because his ECU maxes out and does EXACTLY what mine does.

Somehow measure the MAF signal. IF you see more than 4.8, you need a bigger flowing maf.....

power-fc can mesure maf signal

The MAF setting is on SuperGC8(which is a stock MAF w/ a intake). my MAF voltage is going up to 4.8V which is about 1bar. For some reason i have a hard time beliving that its the MAF. There are allot of ppl on here that are running 17-18PSI on a stock maf and a PFC.

The MAF setting is on SuperGC8(which is a stock MAF w/ a intake). my MAF voltage is going up to 4.8V which is about 1bar. For some reason i have a hard time beliving that its the MAF. There are allot of ppl on here that are running 17-18PSI on a stock maf and a PFC.

I didnt experience maf issues until about 20psi(blow through setup), but I gained 40whp at same boost levels by switching to a Q45 maf.

Change you plugs and report back.

4.8 is really close to maxed have you ever seen any values above 4.8?

i know the G maf is way way smaller than the ej20k and the 205/7

Exceeding the limits of your equipment is a bad idea when your computer is depending on the readings to safely run your car. You should look into something that can handle more air flow like Q45 or Z32. Both are compatible with PFC.

I still say the original problem was the plugs though...

I know the one guy I talked to running a Power FC said he immediately pulls several degrees of timing from the stock tune. Remember, the stock tune in the thing was for 100RON gas, which isnt alot higher that what you can get some places here (its about 94.5-95 on the US scale) but if you are in Cali or one of those places getting the 91 crap, you are most likely getting detonation and the sucker is pulling timing to compensate.

The highest my MAF voltage that i will hit is 4.880V. I hit that when my car is almost up to temp. When its at full opertating temp i cant even go above 4.75 becouse of the loading up.

I just figured out how to adjust the boost levels properly tonight with the pfc. If you scroll over there is a second set of numbers that controls (I think) how fast the boost comes on, try starting with those numbers all the down at like 20 and then build up from there and see if it goes away. I was able to get the boost to come up much smoother and no hesitations by adjusting this value. If you just adjust boost pressure, it's gonna hesitate without adjusting the other numbers. Also, 1,2,3,and 4 are all different boost levels that will get saved and you can switch between them if you didn't know. Pretty cool.

What kind of vacuum is your motor seeing at idle?

I just realized you were having some electrical issues. Ground the hell out of the battery to the block and body and see what happens.... I had a hell of a time once when I had a bad battery to body ground. Barely made it home from the track....

the boost setting is realy cool. However if i set my target boost anything over 1.0 it will throw a CEL. And at idle my PFC is saying my vacume is 550ish and my guage is reading 400ish...for some reason my PFC map sensor values are off, but its to hard to recalibrate.
Reddevil i was thinking about that also. Im going to make my own ground kit. What guage wire do i need?

WOOT WOOT!!!
Got the problem fixed. Put in a set of stock heat range copper NKG's gapped at .o25 and got rid of my problem. My low RPM drivibility is 10X better, i am now able to hit 1.2bar of boost with only tiny hesitation (need to pull some timing up top, hitting like 50knock).The plugs i pulled out where 1 step colder NKG's gapped at .028. Other then the knock up top, it runs like a champ.
Next on the list is a bigger MAF. My MAF voltage was as high as 4.95V.

Thank you guys for all your help.
Kirill

woot! glad you got it fixed kirill! im on the hunt now to fix my hesitation. and in search of a downpipe :P

woot! glad you got it fixed kirill! im on the hunt now to fix my hesitation. and in search of a downpipe :P

got an hks downpipe made for the ej20g but not like theres much diffrence between ej20's.

WHich style MAF are you running? Got a pic?

im running the black maf, that comes on ej18's and most of other subarus.