Welcome to the North American Subaru Impreza Owners Club Saturday November 27, 2021
Home Forums Images WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Go Back   NASIOC > NASIOC Technical > Factory 2.0L Turbo Powertrain (EJ Series Factory 2.0L Turbo)

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.







* As an Amazon Associate I earn from qualifying purchases. 
* Registered users of the site do not see these ads. 
Reply
 
Thread Tools Display Modes
Old 11-14-2021, 12:42 PM   #1
wolfgang116
Scooby Newbie
 
Member#: 527058
Join Date: Oct 2021
Location: Wisconsin
Vehicle:
2003 WRX
Midnight Black Pearl

Default Data log chasing down P0172... possible tuning?

Okay guys, I've been doing my research and tried ruling out what I could from what others have found on the forum, but I could use some expertise if anyone is willing to help. This may be a long post, but I want to cover everything I know.

Car has had a stumbling issue for the past year or so, my FIL (previous owner) said it started after he got gas somewhere he normally didn't. He replaced the MAF (Walker brand from Amazon) & new spark plugs and it mostly went away. Later he found his up-pipe flange had broken, so he replaced with a stainless catless pipe. He said he's had engine lights come and go, never solved them because his county didn't require annual inspections.

Now I have the car, and my county needs no CEL to pass inspection. I'm throwing a P0172 engine code, and have rough idle on startup. I've reset the code three times (between each step of troubleshooting) and the light always triggers while I'm on cruise control (usually on the highway) with low load, showing ShortFT of -19 and LongFT -15.6. I've put about 500 miles on the car since I got it averaging 19.3 MPG.

Here's what I've done to find the problem:

1. Normal new ownership Oil change, oil filter, fuel filter, injector/fuel cleaner, clean MAF first day of ownership. Did resistor mod to up-pipe. Drove fine for a day then threw the code.

2. Did some research, built a pressure tester to look for vacuum leak. Factory turbo inlet was completely fried, installed Tomei silicone turbo inlet. FPR vacuum line was off, so I replaced it and a few other brittle hoses. Cobb K&N filter had cracks around outside, replaced with new K&N (but I don't think pre-MAF would matter for leaks?). Re-seated and checked all other vacuum and boost lines.

3. Noticed battery ground strap was loose, replaced battery terminal and cleaned all engine bay ground points, new NGK BKR6EGP spark plugs (old looked slightly blackened, but not bad).

3. Cleaned IACV and new gasket. New PCV and hoses from dealer.

4. Bought Tactrix cable and did my first data log (will attach Google Drive link below).

At this point, I think it's either my O2 sensor, MAF, or Cobb tune, but I'm not sure what I'm looking for in my data logging. I used Donkey's guide to datalogging with Romraider (clubwrx.net) to pick my parameters for my first couple of logs. It looks like my O2 and MAF are active, but again, I'm new to data logging and unsure what I'm looking at.

Would appreciate any insights or thoughts you guys have! I think I need to do another datalog from cold start with a few 3rd gear pulls, but what I have attached below is a quick run to the store to see if anything is noticeable to you guys.

The Car: 2003 WRX, father-in-law owned the car since 2005 when he did the Cobb "Stage 3" with VF39, STI fuel pump, STI injectors, Cobb catless TBE, JDM up pipe (with resistor mod), Stage 2 clutch, STI RA gear set. It's on their 93 octane tune now, but AP1 will not connect anymore, so it's stuck there.

Click here to get the datalog file.
* Registered users of the site do not see these ads.
wolfgang116 is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 11-14-2021, 04:13 PM   #2
wolfgang116
Scooby Newbie
 
Member#: 527058
Join Date: Oct 2021
Location: Wisconsin
Vehicle:
2003 WRX
Midnight Black Pearl

Default

As a sort of update, I unplugged the O2 sensor while the car was idling... no change. Then, I unplugged the MAF while the car was idling, and the RPM raised up (from 800ish to 1400ish). Plugged it back in and it bogged down again. Shut the car off and restarted, now it dies the ever I unplug the MAF.

I don't think this rules my MAF is bad, but rather than it defaults to programmed not live data for A/F mixture, possibly pointing to my O2 sensor?
wolfgang116 is offline   Reply With Quote
Old 11-17-2021, 12:36 AM   #3
wolfgang116
Scooby Newbie
 
Member#: 527058
Join Date: Oct 2021
Location: Wisconsin
Vehicle:
2003 WRX
Midnight Black Pearl

Default

After more research and some advice from the guys on the Bugeye Mafia Facebook page, I went ahead and purchased a new Denso MAF and re-cleaned my grounds, specifically focusing on the intake manifold ground points. I unplugged the negative terminal with key in "ON" position for a few minutes to reset ECU, then started the car and let it idle for 10 minutes.

Car seemed to idle much better, and initially I thought my problem was solved. As soon as I got to "mexico", I opened it up 1-3 gears. At about 6000RPM, bad bucking in each gear, and a flashing engine light. When I stop, I read using my code reader (left the laptop at home). No stored or pending codes. I do it again, and same thing, bad misfire at 6000RPM and flashing light until I slow to an idle. I went home immediately and grabbed the laptop to log a drive.

If interested, click here for the log file.

I'm very confused... I have a new MAF plug coming in the mail because I noticed that two of the wires casings have been broken, but connection seems to be good (ground wire was actually partially broken but I repaired that for the time being). Remember, initially I was chasing a P0172 Rich Fuel Mixture code... I haven't triggered the same rich mixture code yet (usually shows up after a day or two) but this misfire code is new (I do the exact same drive every time I work through the problem for consistency).

Any suggestions?
wolfgang116 is offline   Reply With Quote
Old 11-17-2021, 01:40 AM   #4
D-Rodman
Scooby Specialist
 
Member#: 110078
Join Date: Mar 2006
Location: Long Island N.Y.
Vehicle:
02 Bugeye JDM STi
OBP BLACK

Default

How new are your coilpacks ?
D-Rodman is offline   Reply With Quote
Old 11-17-2021, 02:56 PM   #5
wolfgang116
Scooby Newbie
 
Member#: 527058
Join Date: Oct 2021
Location: Wisconsin
Vehicle:
2003 WRX
Midnight Black Pearl

Default

Quote:
Originally Posted by D-Rodman View Post
How new are your coilpacks ?
Unknown, as far as I know they could be original to the car. Is there anything I could log to inform me if those are causing it? I guess I could relocate Cylinder 1 or 2 coil packs to 3 or 4 position and see if the misfire follows it. I've never thrown a misfire code until this last run, wondering if it truly is an issue at the cylinder or just a misfire from upstream data anomalies...
wolfgang116 is offline   Reply With Quote
Old 11-17-2021, 03:20 PM   #6
kopele
Scooby Newbie
 
Member#: 363007
Join Date: Jul 2013
Chapter/Region: MWSOC
Location: MO
Vehicle:
2008 STI
Black

Default

Are you sure the Cobb map is still installed? Are you able to read the map with ECUFlash?
Vacuum line to fuel pressure regulator connected with no leaks?
kopele is offline   Reply With Quote
Old 11-17-2021, 03:46 PM   #7
wolfgang116
Scooby Newbie
 
Member#: 527058
Join Date: Oct 2021
Location: Wisconsin
Vehicle:
2003 WRX
Midnight Black Pearl

Default

Quote:
Originally Posted by kopele View Post
Are you sure the Cobb map is still installed? Are you able to read the map with ECUFlash?
Vacuum line to fuel pressure regulator connected with no leaks?
That is a good question. Is there a way I can check with Tactrix/ECUFlash to see if the Cobb tune is still loaded? My AccessPort 1 will not communicate with the ECU anymore. Dumb question, but no amount of dead battery or reset (unplug negative and drain power from system) would revert back to stock tune, would it?

Yes, new vacuum line to fuel pressure regulator installed. When I got the car, the vacuum line was disconnected, but since has been replaced and problem persists.
wolfgang116 is offline   Reply With Quote
Old 11-18-2021, 12:14 PM   #8
kopele
Scooby Newbie
 
Member#: 363007
Join Date: Jul 2013
Chapter/Region: MWSOC
Location: MO
Vehicle:
2008 STI
Black

Default

I'm not super familiar with AccessPort, but I know that it "marries" to your ECU when you install a map and you have to unmarry it to go back to stock. While married other devices will not be able to read the map from the ECU. Get your stock map from here, open it in ECUFlash and try to compare it to your ECU, or try reading current map from ECU. If ECUFlash fails, you'll have to contact COBB and see what you can do to fix the AccessPort.
Maps are written to the ECU permanently, so dead battery and ECU resets will not remove or revert it.
kopele is offline   Reply With Quote
Old 11-24-2021, 10:39 AM   #9
wolfgang116
Scooby Newbie
 
Member#: 527058
Join Date: Oct 2021
Location: Wisconsin
Vehicle:
2003 WRX
Midnight Black Pearl

Default

Thanks for the reply. From my research, it looks like the whole "locked to ECU" thing started with AP V2. V1 is still married from the device standpoint, but the ECU can still be overwritten and even current maps can be pulled from the ECU.
wolfgang116 is offline   Reply With Quote
Old 11-24-2021, 10:49 AM   #10
wolfgang116
Scooby Newbie
 
Member#: 527058
Join Date: Oct 2021
Location: Wisconsin
Vehicle:
2003 WRX
Midnight Black Pearl

Default

As a brief update on the situation... I rewired the MAF plug where it splits off the main harness, replaced all 4 coil packs, and re-replaced the spark plugs with copper variants (verified gaps, read a couple other similar situations that this fixed).

I have not gotten the original P0172 that caused this whole wild goose chase, but I can still consistently throw a cylinder 1 and 2 misfire when the car gets to about 5000 RPM until about 5500 RPM. I can misfire if I'm at partial throttle, which still makes me think it's not a boost leak.

Any ideas? Current thought is to just stay away from 5k RPM and get my emissions test done so I'm not so under the wire on time.

As far as the cause... I can imagine that my FPR is toast from having no vacuum hookup for who knows how long, or that somehow my Cobb tune is jacked up. I guess long shot would be either cylinder 1 & 2 injectors, but seems weird that only those two would show up randomly like this. As I said before, when I got the car, it would throw the rich code, but no amount of high RPM hooning could throw a misfire. Something changed when I fixed all the other problems chasing this. I purchased a XPT 2.5 tune and 3 port EBCS to load on the car, but trying to rule out anything else mechanical before I go open source.
wolfgang116 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

All times are GMT -4. The time now is 11:09 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2021 Axivo Inc.
Copyright ©1999 - 2019, North American Subaru Impreza Owners Club, Inc.

As an Amazon Associate I earn from qualifying purchases.