Welcome to the North American Subaru Impreza Owners Club Monday May 30, 2016
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Go Back   NASIOC > NASIOC Technical > Factory 2.5L Turbo Powertrain (EJ Series Factory 2.5L 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.
* Registered users of the site do not see these ads. 
Reply
 
Thread Tools Display Modes
Old 07-27-2015, 12:53 PM   #1
BugEyeOrBust
Scooby Newbie
 
Member#: 328097
Join Date: Aug 2012
Chapter/Region: SCIC
Location: Culver City, Los Angeles
Vehicle:
2006 STI
WRB

Default Maybe you guys can help...(another P0171 thread)

Here's some necessary info:
2006 STI w/ 46k miles
Blouch 20G, APS FMIC, Turbosmart BOV
DW 1000cc injectors and Perrin rails, Walbro 255(new)
50/50 water/meth injection (coolingmist)
Other mods as well but IMO less relevant.
Tuned by Sean at Church. Has been running GREAT for 25k.

Problems:
P0171 - Lean bank 1
Knock (see data log) (scroll down for a 4th gear pull)https://docs.google.com/spreadsheets...it?usp=sharing

The car drives "normal" to me. No issues with it at all. However, the data says otherwise. The only thing I've noticed to be "different" while driving is that the car pops and backfires a bit when I let off the throttle.

What has been done:
- Smoke test, no leaks
- Fuel pressure tested, fine
- Fuel pump and lines changed just because
- Hooked up to dyno/wideband to check numbers, matches OBD reading meaning my o2 is likely okay.
- Ran a different MAF from another car for about a minute and numbers didn't change much. I think this is the issue but I'm unsure and Paul at YimiSport didn't think this was a concern.

Questions:
- Can my MAF still be the issue? (I think so since it wasn't tested much)
- Are the P0171 and knock related? Or did I find two separate issues?
- What are some other suggestions to check when dealing with this?
* Registered users of the site do not see these ads.
BugEyeOrBust is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 07-27-2015, 01:00 PM   #2
MrTris
Scooby Specialist
 
Member#: 346921
Join Date: Feb 2013
Chapter/Region: NWIC
Location: Tacompton
Vehicle:
2005 LGT
SWP

Default

A friend is having a similar issue, albeit with a different mod list. Just replaced the inlet, code still pops. In for some learning -
MrTris is offline   Reply With Quote
Old 07-27-2015, 01:10 PM   #3
BugEyeOrBust
Scooby Newbie
 
Member#: 328097
Join Date: Aug 2012
Chapter/Region: SCIC
Location: Culver City, Los Angeles
Vehicle:
2006 STI
WRB

Default

Quote:
Originally Posted by MrTris View Post
A friend is having a similar issue, albeit with a different mod list. Just replaced the inlet, code still pops. In for some learning -
Yeah this code seems to be a pain to track down, and when you combine it with some knock from time to time, it's extremely confusing. I wish him luck lol. Hopefully I can get a bit of decent info out of this. I'm still assuming it's the MAF, just haven't had time or money to get a new one. (recently unemployed)
BugEyeOrBust is offline   Reply With Quote
Old 07-27-2015, 01:19 PM   #4
MrTris
Scooby Specialist
 
Member#: 346921
Join Date: Feb 2013
Chapter/Region: NWIC
Location: Tacompton
Vehicle:
2005 LGT
SWP

Default

Quote:
Originally Posted by BugEyeOrBust View Post
Yeah this code seems to be a pain to track down, and when you combine it with some knock from time to time, it's extremely confusing. I wish him luck lol. Hopefully I can get a bit of decent info out of this. I'm still assuming it's the MAF, just haven't had time or money to get a new one. (recently unemployed)

He's already replaced the MAF (after I kept telling him, it's the inlet..) and now the inlet is new as well. Code still came up after reset and initial test drive, and on subsequent resets, as well. Normally, the code is consistent with a worn turbo inlet, particularly due to tearing at the compressor snout. How's your inlet looking, OP?
MrTris is offline   Reply With Quote
Old 07-27-2015, 01:31 PM   #5
BugEyeOrBust
Scooby Newbie
 
Member#: 328097
Join Date: Aug 2012
Chapter/Region: SCIC
Location: Culver City, Los Angeles
Vehicle:
2006 STI
WRB

Default

Well, as far as I know it's fine. BUT, if it was worn and torn wouldn't that show in a smoke test? Because I had zero leaks.
BugEyeOrBust is offline   Reply With Quote
Old 07-27-2015, 02:03 PM   #6
MrTris
Scooby Specialist
 
Member#: 346921
Join Date: Feb 2013
Chapter/Region: NWIC
Location: Tacompton
Vehicle:
2005 LGT
SWP

Default

Quote:
Originally Posted by BugEyeOrBust View Post
Well, as far as I know it's fine. BUT, if it was worn and torn wouldn't that show in a smoke test? Because I had zero leaks.
Not necessarily -- it tends to get icky around where it meets the turbo due to oil saturation, which accelerates its deterioration.
MrTris is offline   Reply With Quote
Old 07-27-2015, 02:08 PM   #7
BugEyeOrBust
Scooby Newbie
 
Member#: 328097
Join Date: Aug 2012
Chapter/Region: SCIC
Location: Culver City, Los Angeles
Vehicle:
2006 STI
WRB

Default

Well, I'll add it to the list to take a look. I'm going through the car on Wednesday so I'm hoping to compile a list.
BugEyeOrBust is offline   Reply With Quote
Old 07-28-2015, 07:22 AM   #8
svltrack
Scooby Specialist
 
Member#: 391110
Join Date: May 2014
Location: Pennsylvania
Vehicle:
15' STI

Default

Add AFR to your log as well as A/F Correction 1 and do a new log. Have you cycled more than this tank of gas through the car since seeing issues with knock? Any recent work done?

Being as though I would highly doubt Shawn to deliver a car with learned knock across such a wide span and any knock in wot, I would first get the lean issue resolved and then evaluate the knock.
svltrack is offline   Reply With Quote
Old 07-28-2015, 12:39 PM   #9
BugEyeOrBust
Scooby Newbie
 
Member#: 328097
Join Date: Aug 2012
Chapter/Region: SCIC
Location: Culver City, Los Angeles
Vehicle:
2006 STI
WRB

Default

I'll add that to the log and do one later. I've gone through 3 different stations with about half tank each. No recent work, it's literally been in this same tune/power for 25k miles.
BugEyeOrBust is offline   Reply With Quote
Old 07-28-2015, 01:24 PM   #10
BugEyeOrBust
Scooby Newbie
 
Member#: 328097
Join Date: Aug 2012
Chapter/Region: SCIC
Location: Culver City, Los Angeles
Vehicle:
2006 STI
WRB

Default

Quote:
Originally Posted by svltrack View Post
Add AFR to your log as well as A/F Correction 1 and do a new log. Have you cycled more than this tank of gas through the car since seeing issues with knock? Any recent work done?

Being as though I would highly doubt Shawn to deliver a car with learned knock across such a wide span and any knock in wot, I would first get the lean issue resolved and then evaluate the knock.
Oh and my AF Correction 1 is almost always 25%, hence my CEL coming on.
BugEyeOrBust is offline   Reply With Quote
Old 07-28-2015, 02:16 PM   #11
MrTris
Scooby Specialist
 
Member#: 346921
Join Date: Feb 2013
Chapter/Region: NWIC
Location: Tacompton
Vehicle:
2005 LGT
SWP

Default

Quote:
Originally Posted by BugEyeOrBust View Post
Oh and my AF Correction 1 is almost always 25%, hence my CEL coming on.
25% is a bit much.. you definitely have a vac leak somewhere!
MrTris is offline   Reply With Quote
Old 07-28-2015, 02:23 PM   #12
BugEyeOrBust
Scooby Newbie
 
Member#: 328097
Join Date: Aug 2012
Chapter/Region: SCIC
Location: Culver City, Los Angeles
Vehicle:
2006 STI
WRB

Default

I already did a smoke test.....zero leaks anywhere lol.

And yes 25% is definitely too much. That's what causes the CEL. When your car hits that 25% mark too often it will throw the light.
BugEyeOrBust is offline   Reply With Quote
Old 07-28-2015, 03:19 PM   #13
klaas
Scooby Newbie
 
Member#: 336000
Join Date: Oct 2012
Chapter/Region: International
Location: Dubai, UAE
Vehicle:
2005 Impreza STi
WRB

Default

Agree with above you definetly have a vacuum leak. Your long term fuel trim is also very high. I would not be surprised if your turbo inlet is torn.
The smoke test usually don't pressurize the system.
Unless your intake is pressurized you may not find a leak.

So either
1. Pressurize intake with an air compressor and spray with soapy water and watch for bubbles. Be careful with the pressure, no more than 8-10 psi or you will blow your cam seals.
2. Spray with carb cleaner while engine is idling. Spray on the intake hoses and vacuum lines all the way to your throttle body. Listen for any sudden change in idle. If you have an AP you can also watch for sudden changes in AF correction 1.

Last edited by klaas; 07-28-2015 at 03:25 PM.
klaas is offline   Reply With Quote
Old 07-28-2015, 04:50 PM   #14
BugEyeOrBust
Scooby Newbie
 
Member#: 328097
Join Date: Aug 2012
Chapter/Region: SCIC
Location: Culver City, Los Angeles
Vehicle:
2006 STI
WRB

Default

Thank you for explaining that. I guess I didn't think of it that way, but you gave a valid reason to go back and re-check for vac leaks with pressure. That's the kind of response I was hoping for haha. I'll take a look.

In the meantime, here's a slightly scarier data log with more feedback knock and some new values all around. For the record, this was starting at a stop light, going through 1st and 2nd somewhat normal, then pulling through 3rd and 4th.

https://docs.google.com/spreadsheets...it?usp=sharing
BugEyeOrBust is offline   Reply With Quote
Old 07-29-2015, 10:55 PM   #15
nfmRc8q
Scooby Newbie
 
Member#: 317876
Join Date: Apr 2012
Default

Quote:
Originally Posted by klaas View Post
Agree with above you definetly have a vacuum leak. Your long term fuel trim is also very high. I would not be surprised if your turbo inlet is torn.
The smoke test usually don't pressurize the system.
Unless your intake is pressurized you may not find a leak.

So either
1. Pressurize intake with an air compressor and spray with soapy water and watch for bubbles. Be careful with the pressure, no more than 8-10 psi or you will blow your cam seals.
2. Spray with carb cleaner while engine is idling. Spray on the intake hoses and vacuum lines all the way to your throttle body. Listen for any sudden change in idle. If you have an AP you can also watch for sudden changes in AF correction 1.
+1
what he said ^^^^^

also double check your BOV for leaks under pressure and vaccum

I tracked down a p0171 for a while on my old bugeye and it ended up with a wrong mass air flow scaling.
nfmRc8q is offline   Reply With Quote
Old 07-29-2015, 11:52 PM   #16
svltrack
Scooby Specialist
 
Member#: 391110
Join Date: May 2014
Location: Pennsylvania
Vehicle:
15' STI

Default

Quote:
Originally Posted by klaas View Post
Agree with above you definetly have a vacuum leak. Your long term fuel trim is also very high. I would not be surprised if your turbo inlet is torn.
The smoke test usually don't pressurize the system.
Unless your intake is pressurized you may not find a leak.

So either
1. Pressurize intake with an air compressor and spray with soapy water and watch for bubbles. Be careful with the pressure, no more than 8-10 psi or you will blow your cam seals.
2. Spray with carb cleaner while engine is idling. Spray on the intake hoses and vacuum lines all the way to your throttle body. Listen for any sudden change in idle. If you have an AP you can also watch for sudden changes in AF correction 1.
The leak could be anywhere, to pinpoint a turbo inlet is a bit presumptuous. It also might not be a leak at all.

Agreed that a boost leak test is a great next step to diagnose what is going on. MAKE SURE TO READ THE THREADS ON HOW TO PERFORM THIS TEST PROPERLY AND DO NOT SIMPLY PRESSURIZE THE SYSTEM WITH AN AIR COMPRESSOR. Take off the oil filler cap to depressurize the crankcase. Also, use carb cleaner at your own risk. It is pretty aggressive stuff for many polymers.
svltrack is offline   Reply With Quote
Old 07-30-2015, 06:18 AM   #17
klaas
Scooby Newbie
 
Member#: 336000
Join Date: Oct 2012
Chapter/Region: International
Location: Dubai, UAE
Vehicle:
2005 Impreza STi
WRB

Default

Quote:
Originally Posted by svltrack View Post
The leak could be anywhere, to pinpoint a turbo inlet is a bit presumptuous. It also might not be a leak at all.

Agreed that a boost leak test is a great next step to diagnose what is going on. MAKE SURE TO READ THE THREADS ON HOW TO PERFORM THIS TEST PROPERLY AND DO NOT SIMPLY PRESSURIZE THE SYSTEM WITH AN AIR COMPRESSOR. Take off the oil filler cap to depressurize the crankcase. Also, use carb cleaner at your own risk. It is pretty aggressive stuff for many polymers.
I never said it was the inlet hose!

But I agree with the carb cleaner, I did some googling and its not good for rubber hoses. Most electrical / contact cleaner should be safe, but you should read the label to be sure.
And before OP do any tests/troubleshooting he should obviously find the relevant posts here so they can be performed correctly. Both test should be done with caution!

As said in other posts MAF could also be the culprit.
Try to clean the MAF. A failing MAF usually results in higher fuel trims.
A bad tune with wrong MAF scaling could also be the cause.

And I'm sure there could other causes as well these are just the most common.
klaas is offline   Reply With Quote
Old 07-30-2015, 06:32 AM   #18
klaas
Scooby Newbie
 
Member#: 336000
Join Date: Oct 2012
Chapter/Region: International
Location: Dubai, UAE
Vehicle:
2005 Impreza STi
WRB

Default

klaas is offline   Reply With Quote
Old 07-30-2015, 07:45 AM   #19
svltrack
Scooby Specialist
 
Member#: 391110
Join Date: May 2014
Location: Pennsylvania
Vehicle:
15' STI

Default

Quote:
Originally Posted by klaas View Post
I never said it was the inlet hose!.
This debate has zero merit for the op. All I was trying to convey was that keeping an open mind during diagnostics is often critical to finding problems.
svltrack is offline   Reply With Quote
Old 07-30-2015, 07:48 AM   #20
klaas
Scooby Newbie
 
Member#: 336000
Join Date: Oct 2012
Chapter/Region: International
Location: Dubai, UAE
Vehicle:
2005 Impreza STi
WRB

Default

No disagreement in that statement.
klaas is offline   Reply With Quote
Old 07-30-2015, 01:47 PM   #21
BugEyeOrBust
Scooby Newbie
 
Member#: 328097
Join Date: Aug 2012
Chapter/Region: SCIC
Location: Culver City, Los Angeles
Vehicle:
2006 STI
WRB

Default

Well thanks guys for chiming in. After many tests, I officially have ringland issues....
BugEyeOrBust is offline   Reply With Quote
Old 07-30-2015, 04:11 PM   #22
klaas
Scooby Newbie
 
Member#: 336000
Join Date: Oct 2012
Chapter/Region: International
Location: Dubai, UAE
Vehicle:
2005 Impreza STi
WRB

Default

Sucks, but also an opportunity.
What's your next step?
klaas is offline   Reply With Quote
Old 07-30-2015, 04:53 PM   #23
BugEyeOrBust
Scooby Newbie
 
Member#: 328097
Join Date: Aug 2012
Chapter/Region: SCIC
Location: Culver City, Los Angeles
Vehicle:
2006 STI
WRB

Default

Bought some Wiseco pistons, Carillo rods, and King bearings. Just gotta get the better ARP studs, a gasket kit, timing belt kit, and some cams.
BugEyeOrBust is offline   Reply With Quote
Old 07-30-2015, 05:14 PM   #24
klaas
Scooby Newbie
 
Member#: 336000
Join Date: Oct 2012
Chapter/Region: International
Location: Dubai, UAE
Vehicle:
2005 Impreza STi
WRB

Default

Sounds like a great plan, good luck.
klaas is offline   Reply With Quote
Old 07-30-2015, 05:25 PM   #25
BugEyeOrBust
Scooby Newbie
 
Member#: 328097
Join Date: Aug 2012
Chapter/Region: SCIC
Location: Culver City, Los Angeles
Vehicle:
2006 STI
WRB

Default

Thanks! It might be a little bit before the build is done but it should be pretty glorious after.
BugEyeOrBust 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 03:16 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2016, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2016 Axivo Inc.
Copyright ©1999 - 2016, North American Subaru Impreza Owners Club, Inc.