Overboost problem on 2004 WRX with stock ECU settings

User topics relating to software that logs data from ECUs

Moderator: Freon

Overboost problem on 2004 WRX with stock ECU settings

Postby snake2332 - n00b » Tue Mar 11, 2008 11:34 am

I bought a used 2004 WRX (USDM). I could tell the boost was oscillating. Let me warn you, I have never tuned a car before, so I'm a newbie but willing to learn. I bought a boost gauge and sure enough when I floor it, the boost hits about 16 or 17psi then drops to 10 then hits 15 then 11, basically honing in on about 13psi. At the suggestion of clubwrx.com people, I tried a TurboXS bypass valve. That didn't change it. I got a tactrix cable and flashed the ECU with the *520.hex stock ROM. That didn't change it, as I figured it wouldn't since it looked like my ECU settings were already stock.

So does this sound like a commonly known problem? I'm thinking of adjusting the wastegate arm and checking the restrictor pill. All the intercooler hoses look good. The car is stock except for Samco intercooler hoses and the resonator box from the intake is missing. It had the problem before installing the Samco hoses too. I took the TurboXS BPV off and put the stock one back on since that didn't help alleviate my problem.

Any help would be greatly appreciated. I am going to try data logging it tonight probably. I just got the tactrix cable today so I'm still learning how this is all done. Thanks!
snake2332 - n00b
 
Posts: 23
Joined: Thu Mar 06, 2008 6:53 am
Location: Montana, USA

Postby wrx_aruba » Tue Mar 11, 2008 6:59 pm

Hello,

Check your restrictor pill, i had kinda the same problem, was fixed by installing new restrictor pill and oem turbo compressor hose oem wastegate hose...
User avatar
wrx_aruba
 
Posts: 34
Joined: Mon Aug 14, 2006 10:21 am

Postby snake2332 - n00b » Wed Mar 12, 2008 5:28 am

OK I'll try that out. Thanks for the tips.
snake2332 - n00b
 
Posts: 23
Joined: Thu Mar 06, 2008 6:53 am
Location: Montana, USA

Postby snake2332 - n00b » Thu Mar 20, 2008 1:12 pm

Put in new restrictor pill and replaced a couple hoses right there near the turbo because they were old and cracking. Still didn't help the overboosting problem. I think I've narrowed it down to the wastegate actuator arm. I'm going to play with that tonight and see what happens.
snake2332 - n00b
 
Posts: 23
Joined: Thu Mar 06, 2008 6:53 am
Location: Montana, USA

Postby snake2332 - n00b » Thu Mar 20, 2008 1:19 pm

I'll do a datalog tonight probably and get some more exact readings. Does anyone have experience running 16psi on a mostly stock 04 WRX? How bad is it for it? Can the stock intercooler keep up with it? I was thinking if I can't get the stupid turbo to stop overboosting, I could change the ECU settings to 16psi for target boost. I don't really want to break shit though...
snake2332 - n00b
 
Posts: 23
Joined: Thu Mar 06, 2008 6:53 am
Location: Montana, USA

Postby snake2332 - n00b » Fri Mar 21, 2008 5:53 am

I took off the turbo heat shield and shortened the wastegate arm 2.5 rotations. The boost levels seemed the same. I should have data logged it before doing this, but I didn't. Anyway, I logged it after shortening the arm. I attached the results of my data log. I'm not sure how useful it will be.

When I floor it in 4th gear at about 3000 RPMs, my Autometer boost gauge goes up to about 16psi then backs off to 10 psi then goes back to around 13 psi. Enginuity data logger shows max "target" boost of 11.62psi and stays at 11.62 psi while my boost gauge goes from 16 to 13 psi. When my boost gauge shows a solid 13psi, data logger shows 11.62psi. When I floor it in 2nd gear, my gauge hit about 17-18 psi and did the whole "back off to 10 psi, the back up to 14psi", however, the data logger still shows 11.62 as the max target boost level.

It seems like the target boost should be ~13psi with 100% throttle (13.63psi minus atmospheric compensation of about 5%). So the ECU has no sensor or reading for the actual current boost level, right?

The CEL is supposed to come on somewhere around 15.8psi at 13.20 atmospheric pressure, and my boost gauge is showing me exceeding that and yet no CEL light or fuel cut. Maybe because of the delay setting in the ECU? It says "boost limit CEL delay" set to 31...31 what? I don't know, it just says raw ecu value. Milliseconds perhaps?

The wastegate duty cycle maxed out at 82.75%, not sure if that's good or not. In the ECU I see 18.8% compensation and 96.1% for max wastegate duty cycle.

What the hell is going on with my turbo? Is there other info I should log and should I do it at higher RPMs, or should I start the log at like 3000rpm in 3rd gear then floor it and stop the log when I hit redline?

Thanks for any help you guys provide.
Attachments
ECU log - Troubleshooting overboost.jpg
ECU log - Troubleshooting overboost.jpg (77.37 KiB) Viewed 12014 times
snake2332 - n00b
 
Posts: 23
Joined: Thu Mar 06, 2008 6:53 am
Location: Montana, USA

Postby snake2332 - n00b » Fri Mar 21, 2008 8:49 am

To sum it up, I have eliminated the following items as causing the problem:

1) BPV - replaced with TurboXS, then back to stock
2) Restrictor pill & hoses - replaced with new OEM
3) ECU settings - flashed to stock *520 version

And I'm currently adjusting the wastegate arm. I'll adjust it some more and post another log.
snake2332 - n00b
 
Posts: 23
Joined: Thu Mar 06, 2008 6:53 am
Location: Montana, USA

Postby pezzar » Sun Mar 23, 2008 3:48 pm

check the wastegate duty cycle values. The higher the duty cycle % the more boost. lower cycle allows gases to bypass the turbine and so lower boost pressures.

just a thought, have you checked the wastegate solenoid is operating correctly.

check here
http://www.ken-gilbert.com/wrx/STi_Manu ... ION%20(STi)/01.%20FUEL%20INJECTION%20(FUEL%20SYSTEMS)/13.%20Wastegate%20Control%20Solenoid%20Valve.pdf
pezzar
 
Posts: 11
Joined: Sun Feb 24, 2008 3:05 am

Postby snake2332 - n00b » Mon Mar 24, 2008 5:25 am

Oops, I meant to say I "lengthened" the arm, not "shortened" it. I lengthened it some more, another 2.5 rotations, and now I definitely see a difference. It seems to hit max boost of 12psi and not over boost, but it's a lot slower to reach max boost. I can be going 3000rpm in 3rd gear, floor it and it slowly rises to 12psi by the time I hit about 5500rpm. Before, it would raise the boost way faster, like by the time it hit 3500rpm from 3000rpm, but then over boost which is no good. I'll do some higher RPM tests tonight.

Anyway, I think it's good now. I might record a video of the data logger tonight. I found a good freeware app called Cam Studio to record an area of the screen. I did it in H264 format and the video is only like 73kb for 10 seconds without audio. Some low quality audio recording doubles the size of the avi file.
snake2332 - n00b
 
Posts: 23
Joined: Thu Mar 06, 2008 6:53 am
Location: Montana, USA

Postby snake2332 - n00b » Mon Mar 24, 2008 12:06 pm

I've read some more now and I see how to do a log with the defogger switch. Also I see what parameters to log and which one equates to boost. I'll be flashing a stage 1 map tonight. Do you think a 91 octane stage 2 map running lower 17's for psi of boost would be a good base with the following mods:

Invidia catless uppipe
Samco IC hoses
Iridium one-step-cooler spark plugs
Light-weight pulley kit
Cobb SF intake
Gutted down-pipe

The cat closer to the muffler still remains, as well as the stock muffler.
snake2332 - n00b
 
Posts: 23
Joined: Thu Mar 06, 2008 6:53 am
Location: Montana, USA

Postby snake2332 - n00b » Mon Mar 31, 2008 10:41 am

I think I'll stick with this stage 1 setup because it's hitting ~15.5psi and feels pretty good. I don't want to break my car, so it's good enough. I attached a couple logs, one of a 2nd & 3rd gear run, another of a 4th gear run. I am still new to this, so I was hoping someone could check to see if my timing settings are bad or if anything looks like it's way off from what it should be.
Attachments
enginuitylog_20080328_193856.csv
4th gear
(8.72 KiB) Downloaded 712 times
enginuitylog_20080328_193412.csv
2nd & 3rd gear
(7.26 KiB) Downloaded 692 times
snake2332 - n00b
 
Posts: 23
Joined: Thu Mar 06, 2008 6:53 am
Location: Montana, USA

Knock correction

Postby dougkmcse » Sat May 03, 2008 8:03 am

Feedback Knock Correction* (degrees)
Fine Learning Knock Correction* (degrees)
You should also data log these two. The are a finner way to watch for knock. I also have a 04 WRX Welcome to tunning. To me the log looks good.
dougkmcse
 
Posts: 6
Joined: Thu Mar 20, 2008 6:49 pm

Postby snake2332 - n00b » Tue May 06, 2008 7:17 am

Cool, thanks. Yeah, I log those parameters now. I'm going to look up some stuff on what the optimal AFR should be. Right now it's 11.02 which is kinda rich I think.
snake2332 - n00b
 
Posts: 23
Joined: Thu Mar 06, 2008 6:53 am
Location: Montana, USA


Return to Data Logging Software

Who is online

Users browsing this forum: No registered users and 5 guests