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Old 01-14-2008, 12:01 AM   #1
SPRSUBY
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Unhappy My Subie has a problem. Please help if you can

I have an '02 WRX, stock turbo and I/C, HKS SSQV BPV, turbo-back exhaust, Injen short ram intake, MadDad Headers/UP, UTEC, HyperGround wires, TurboXS ABC crappy boost controller, Exedy spec 1.1 clutch ACT 13+lb flywheel, and STI Rally gears...

I have 2 TXS base maps and a "road tune" my mechanic friend (fellow subie enthusiast for years) made.

What happens is: In any gear, any vehicle speed, any RPM (where I can pass 5 PSI), if I let my boost pass a point somewhere between 5 and 7 PSI, I will get a steady miss on at least one cylinder. It will miss constantly and evenly until I let off the throttle, at which point the engine will still "pull" for a second burning up unused fuel and then pop in my exhaust really nice and return to normal decelleration. If I hold my foot in it I can achieve full boost but have no power. Everything was running fine after I got my tranny in, and then all of a sudden it just started doing this, out of the blue! I suspected my UTEC was messing up, somehow, so I tried unhooking it. Nothing different. I took it to my same Subie enthusiast friend, who at this point worked at Tires Plus, and he brought out the code reader and scanned my codes. I had a MAF sensor code and a Fuel level sensor code. So, I went to NAPA and bought a MAF sensor to try. This didn't change anything. I then took it to my local Subaru dealer, and the lameazz mechanic there pretty much threw up his hands and said with all my mods he couldn't tell anything and sent me on my way less 45 bucks and the hassle of leaving my car with them overnight to give him time to do nothing. So, then I hooked up my UTEC again to get readings on my sensors. the MAF sensor was just reading 5V all the time, and the mechanic at Subaru said I still had a MAF sensor code (yes I reset the ECU when i replaced it the first time) so I got another one from NAPA... no difference. I unhooked the MAF sensor to see what difference it made, and the car ran exactly the same, but in my UTEC i had a low/irregular TPS reading. So I began researching on here and other forums to see what people say about these symptoms... basically they say look for boost leaks. I checked my grounding points, my hoses all look good, nothing out of the ordinary. Oh, and my parking brake light stays on most of the time.... started that LAST winter only when the engine was cold, on a cold day, and now it's always on except when I accelerate from a stop in 1st gear with the engine thoroughly warmed up. I have considered that this may be from a plugged vac hose somewhere, considering that many vehicles will illuminate this light if there is low vac in the system. I am open to any ideas. I don't have a boost leak tester, I am interested in your input on how to properly do this. Has anyone experienced this problem? My car ran great with all the mods I have. Everything was perfect, then one day it just started sputtering past 5psi. I run 92 octane BP gas, my car has 62,000 miles, and it sat a lot in the last year because I had really bad transmission problems and it took a long time to get all that sorted out and reinstalled. I put in new plugs at 40K, have never used injector cleaner. I'm at a loss. Thank you in advance for any and all suggestions that you can give me.

Thanks,
Kevin
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Last edited by SPRSUBY; 01-14-2008 at 12:20 AM.
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Old 01-14-2008, 12:48 AM   #2
MasterKwan
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Until you get the MAF code cleared up, it's pointless to look at anything else. Code doesn't mean the MAF's bad. It means you need to trouble-shoot and find out why the ECU doesn't like what the MAF is saying.

What's the code? MAF shorted high or something? I think it sounds like a wiring or ECU problem.
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Old 01-14-2008, 01:58 AM   #3
kellygnsd
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If your MAF voltage is 5V all the time its not a boost leak. You have problem with you MAF, harness, or ECU. 5V is the max MAF voltage
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Old 01-14-2008, 10:05 AM   #4
Haelan
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Drop the UTEC out of there and hook everything back up to the ECU. Pull the exact codes, and let us know what they are. Try to minimize the amount of crap needed to troubleshoot this one.
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Old 01-14-2008, 12:20 PM   #5
SPRSUBY
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Ok. The code reader at Tires Plus interpretted the code. I believe it just read "MAF Sensor Reading" or some such crap. If I go to Napa or Autozone will their code readers bring up exact codes? I have looked very carefully at all the wiring, including the maf plug and harness. Visually there's nothing wrong. Can you guys recommend the best place to get my codes read short of buying a scan tool? (which i really don't want to do).

Thanks guys for your thoughts. I am going to go recheck my grounding points now, and take another look at my MAF harness and connector
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Old 01-14-2008, 01:45 PM   #6
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Quote:
Originally Posted by SPRSUBY View Post
Can you guys recommend the best place to get my codes read short of buying a scan tool? (which i really don't want to do).
Autozone or Advanced Auto Parts are the two that I've used. Advanced Auto actually provides you with a printout of the code(s), which is nice.
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Old 01-14-2008, 01:58 PM   #7
Rexfan
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I know you checked your wiring....Did you check ground from UTEC? Buddies car was a similar issue. Bad ground was the prob.
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Old 01-14-2008, 02:37 PM   #8
mick_the_ginge
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MAF sensor installed backwards?
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Old 01-14-2008, 02:47 PM   #9
SPRSUBY
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No the MAF is installed the original direction. The plug connection points towards my right headlight. I got my codes from the nice guys at Advance Auto Parts:
P0103 MAF Reading High
P0113
P0461 Fuel Level CKT /Perf
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Old 01-14-2008, 02:48 PM   #10
SPRSUBY
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Also, I just reconnected my rear ground from firewall to transmission. I knew it was unhooked b/c the terminal snapped when I reinstalled the trans. I got my codes cleared and it still runs the same. Do I need to reset the ECU to really see if my problem is fixed?

Thanks for your replies.
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Old 01-14-2008, 03:17 PM   #11
MatchstiK
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I can't help with the major engine stuff, but as far as the parking brake light goes, have you checked your brake fluid level? I was puzzled by the light on in my old Civic, and that was the culprit. Seems pretty basic, but that fixed it quick.
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Old 01-14-2008, 04:01 PM   #12
Bruce Wayne
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Wow you have alot of different parts on your car so it's gonna be tough to pinpoint what is causing the CEL codes and condition because sometimes the CEL codes can act as a chain reaction to each other, and set each other off. For example, alot of subie owners have voiced that a cylinder misfire code can be triggered by exhaust leaks, faulty o2 censors, and even lighter flywheels. In the case of a lighter flywheel, the lighter flywheel can change the acceleration speed of the crankshaft enough that the ECU sees it as a misfire, or "the weight difference at the crank (be it pully, or flywheel) would cause a deviation in angular velocities at specific moments of interia that the ECU is registering and therefore pissing it off." Something you wouldnt expect, but it happens. What I'm trying to say is, your codes can be caused by something you wouldn't expect it from, and your ECU is pissed off and throwing other codes which can cause your car to do weird things and run funny. Worst case scenario, sounds like you just might have to start backtracking the parts back to stock 1 by 1.

So my question to you is, did you install any parts recently? Or going backwards what were the parts you most recently installed.

Last edited by Bruce Wayne; 01-14-2008 at 04:25 PM.
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Old 01-15-2008, 12:47 AM   #13
SPRSUBY
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I do see your point. Most recent is the exedy clutch and flywheel. I think that if I am going to change anything back towards stock, I will start with my BOV, back to stock BPV. I have a friend with an '03 WRX. He offered to let me swap his MAF sensor and maybe his O2 sensor in to try in my car. Hopefully this Sat. afternoon I'll get to try that.

As far as other items I can put back to stock... unhooking the UTEC is a breeze... but then the stock ECU has to try to learn my mods... which i guess is fine up to the point of finding out if my car will boost past 5 psi. When I tried it before, it didn't work, so I hooked the UTEC back up for the sake of reading sensors. I'm crawling under the car tomorrow to check over my O2 harness and plugs. The "chain reaction" thing made me think of a somewhat corroded terminal I noticed there when I reinstalled my tranny and exhaust. I can also put my stock air intake back on for the sake of eliminating some possible variables.

Thanks guys for the ideas. I'm plugging away at it!
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Old 01-15-2008, 01:37 PM   #14
mars636
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You need to find out why your MAF is reading 5v all the time. I believe this is your problem completely. You said it acted the same as when it is unplugged. Check the continuity of the wires from the harnesss to the ecu and the ground from the harness. The reason it only happens at 5psi is because your car is going into open loop. It sees 5v on your maf and then tries to add fuel for 5v of MAF. If you have a wideband to confirm this you will see once you hit 5psi your AFR readings should go rich.
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Old 01-15-2008, 08:21 PM   #15
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Quote:
Originally Posted by mars636 View Post
You need to find out why your MAF is reading 5v all the time. I believe this is your problem completely. You said it acted the same as when it is unplugged. Check the continuity of the wires from the harnesss to the ecu and the ground from the harness. The reason it only happens at 5psi is because your car is going into open loop. It sees 5v on your maf and then tries to add fuel for 5v of MAF. If you have a wideband to confirm this you will see once you hit 5psi your AFR readings should go rich.
Bingo!!!
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Old 01-16-2008, 12:57 AM   #16
SPRSUBY
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Ah! That would explain how when this happens and I let off the gas, I usually notice the engine keeps "pulling" for a second to burn up that extra dump of gas. How do I find which pins on the ECU connect to the MAF harness? Once I find that out, I should be able to test the continuity, as you said, and see if we are losing communication somewhere.

Anyone know the pins on the ECU well enough to know which are the MAF Sensor slots?
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Old 01-16-2008, 02:48 PM   #17
SPRSUBY
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Default wow...duh!

Quote:
Originally Posted by MatchstiK View Post
I can't help with the major engine stuff, but as far as the parking brake light goes, have you checked your brake fluid level? I was puzzled by the light on in my old Civic, and that was the culprit. Seems pretty basic, but that fixed it quick.
wow, good point!! My brakes are original (62,000m) so over time, with wear, the fluid had indeed gotten lower and lower, and just needed topped off. :-D Now at least THAT is fixed.
Thanks!
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Old 01-16-2008, 03:27 PM   #18
mars636
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2002-2003 ecu pinout Here is the ecu pinout.
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Old 01-17-2008, 02:13 PM   #19
SPRSUBY
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Thanks, that'll be a huge help.
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