Welcome to the North American Subaru Impreza Owners Club Tuesday October 16, 2018
Home Forums 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.
* Registered users of the site do not see these ads. 
Closed Thread
 
Thread Tools Display Modes
Old 05-01-2004, 07:44 PM   #1
LTSmash
Scooby Newbie
 
Member#: 32010
Join Date: Jan 2003
Location: so cal
Vehicle:
2006 Legacy GT Wagon
White

Default CEL - P0171 System too lean

last week, i installed my catback (2.5" stromung intermediate and prodrive muffler) and reflashed my ecu using accessport to stage 1, 91 octane. everything was fine for the whole week. today, shortly after i filled up at the gas station the CEL came on. i used accessport to read the CEL and it showed P0171 (system too lean). any ideas on how to fix this?

thanks
* Registered users of the site do not see these ads.
LTSmash is offline  
Sponsored Links
* Registered users of the site do not see these ads.
Old 05-01-2004, 10:34 PM   #2
Uncle Scotty
*** Banned ***
 
Member#: 16200
Join Date: Mar 2002
Vehicle:
OK buy Nates beans
westcoastroasting.com

Default

If you have an aftermarket intake installed....put the stock intake back on....check for loose intake parts/hoses.
Uncle Scotty is offline  
Old 05-01-2004, 11:02 PM   #3
LTSmash
Scooby Newbie
 
Member#: 32010
Join Date: Jan 2003
Location: so cal
Vehicle:
2006 Legacy GT Wagon
White

Default

hmm...intake is all stock, haven't touched it besides replacing the air filter some time ago. i will check the hoses though.

thanks
LTSmash is offline  
Old 05-02-2004, 12:30 AM   #4
MIDNIGHTROCKET
Scooby Specialist
 
Member#: 40625
Join Date: Jul 2003
Location: VA.
Vehicle:
2002 WRX SEDAN
MIDNIGHT BLUE

Default

i had this problem for sooooooooooooooooooooo long, turned out to be a faulty walbro 255lr. fuel pump..just a thought, i know how frustrating it can be
MIDNIGHTROCKET is offline  
Old 05-02-2004, 01:27 AM   #5
dman918
Scooby Specialist
 
Member#: 11202
Join Date: Oct 2001
Chapter/Region: MWSOC
Location: McHenry, IL
Vehicle:
2009 Infiniti G37X
Prev: 2006 STi with stuff

Default

Hmmm. I wonder if it is the fuel pump that is causing my issue.
dman918 is offline  
Old 05-02-2004, 08:51 AM   #6
mixup52
Scooby Specialist
 
Member#: 39691
Join Date: Jul 2003
Location: Ogden Utah
Vehicle:
2002 WRX Wagon
White

Default

It could be that your MAF is dirty as well. I would get one (p0171) all the time. Now I don't get them until I am coasting at high speeds with my clucth in or my car in "N". If you have a front mount it will get the p0171 code from doing the above mentioned.

Chris
mixup52 is offline  
Old 05-02-2004, 07:00 PM   #7
LTSmash
Scooby Newbie
 
Member#: 32010
Join Date: Jan 2003
Location: so cal
Vehicle:
2006 Legacy GT Wagon
White

Default

thanks for your help...the intake connections are ok. i'm not sure how i'd check the fuel pump.

btw, all my components are stock besides the catback and accessport stage 1 reflash i mentioned in my original post.

i ended up using accessport to reset the ecu; just to see if the CEL would come back. so far the CEL hasn't returned.
LTSmash is offline  
Old 05-02-2004, 09:35 PM   #8
CirrusWRX
Scooby Guru
 
Member#: 17439
Join Date: Apr 2002
Chapter/Region: Tri-State
Location: Yardley, PA
Vehicle:
2002 x2 Silver WRX
Sedan, White WRX Wagon

Default

Not sure if it will help, but PAWRX and myself battled a P0171. We compiled the info in this thread - check it out and see if there is anything worth trying.

Good luck!

http://forums.nasioc.com/forums/show...ighlight=p0171
CirrusWRX is offline  
Old 05-03-2004, 11:19 PM   #9
readymix
Scooby Newbie
 
Member#: 59839
Join Date: Apr 2004
Chapter/Region: MWSOC
Location: Cottage Grove, MN
Vehicle:
2004 WRX
Platinum Silver

Default

Ive got the same problem too. And extremely similar setup to LTSmash's setup.
readymix is offline  
Old 05-04-2004, 10:38 AM   #10
CirrusWRX
Scooby Guru
 
Member#: 17439
Join Date: Apr 2002
Chapter/Region: Tri-State
Location: Yardley, PA
Vehicle:
2002 x2 Silver WRX
Sedan, White WRX Wagon

Default

Quote:
Originally posted by readymix
Ive got the same problem too. And extremely similar setup to LTSmash's setup.
Read my link there above - hope it helps!

Any word from Lt. L.T. Smash?

<-- simpsons fan
CirrusWRX is offline  
Old 05-04-2004, 12:50 PM   #11
LTSmash
Scooby Newbie
 
Member#: 32010
Join Date: Jan 2003
Location: so cal
Vehicle:
2006 Legacy GT Wagon
White

Default

CirrusWRX,

well, since the CEL, i've checked the intake connections and exhaust connections. (i was pretty sure it's not related to the exhaust connections since the only thing i've changed was the catback and all the sensors are upstream of that). then i reset my ecu, as i stated above in my previous post. all of this was before the helpful link to your thread. i read your thread and was planning to preform some of your troubleshooting steps, until i read another thread where another member, 'Arnie', has had trouble with his cobb stage 1 running too lean http://forums.nasioc.com/forums/show...62#post6410662

then i saw that readmix was having the same problem and posted in the other thread as well.
Quote:
Originally posted by readymix
I am (was) running Cobb AccessPort Stage 1 91octane on my 04. Today I threw a CEL P0171 System too Lean (Bank 1)
The engine sputtered at idle, and a few times felt like it was going to stall. I let the engine sit for a few hours to cool down. Fired it up, and it ran smooth as normal. CEL still there. Dealership is looking at it tomorrow.
yesterday i noticed my car started acting the same way when i was waiting at idle at a long stop light. so this is leading me to believe that the cobb reflash is the problem. i uninstalled accessport last night, and during my morning commute, the sputtering at idle was gone. i think i'll observe a little while longer to make sure it's the reflash that was actually the problem.

readmix said he's taking his car to the dealer...i'm also waiting for him to post the results from that.
LTSmash is offline  
Old 05-04-2004, 01:17 PM   #12
CirrusWRX
Scooby Guru
 
Member#: 17439
Join Date: Apr 2002
Chapter/Region: Tri-State
Location: Yardley, PA
Vehicle:
2002 x2 Silver WRX
Sedan, White WRX Wagon

Default

Very interesting. I think Arnie is a great guy, and I am totally unequipped to make this "summation" but after reading Arnie's post about his popped motor, I still think it points to the headwork performed on his engine after his accident in combination with a bad tank of gas. I honestly think in the back of my head that there was more damage to his car than just his bent valves, but that is TOTALLY some random gut feeling.

Do you have an 04 or 03? I almost wonder if there is some connection between the AP and 2004 vs. 2002/3, but that's just total speculation. How many miles you have on your car total? How many before AP, how many after? How many on AP BEFORE CEL?

Finally, have you checked the Cobb forums? I seem to recall somebody else getting a CEL, and while my mind is probably playing tricks on me, it MIGHT have been the p0171... might be worth a shot if you haven't already checked it out. And of course, a call to Cobb might not be a bad idea either.

keep us posted. g/l.
CirrusWRX is offline  
Old 05-04-2004, 02:09 PM   #13
LTSmash
Scooby Newbie
 
Member#: 32010
Join Date: Jan 2003
Location: so cal
Vehicle:
2006 Legacy GT Wagon
White

Default

Cirrus,

thanks for your help. i have an '02.

here's my mileage history:

~37,200 - installed AP
~37,630 - CEL came on
~37,750 - uninstalled AP


i realize this may be an uncommon problem related w/ the cobb reflash, but i'm extra cautious. this is my only car and my round trip commute to work is about 90 miles a day, i can't afford to be without a car. i'll check the cobb forums and try to give them a call during my lunch hour.

thanks again
LTSmash is offline  
Old 05-05-2004, 12:42 AM   #14
readymix
Scooby Newbie
 
Member#: 59839
Join Date: Apr 2004
Chapter/Region: MWSOC
Location: Cottage Grove, MN
Vehicle:
2004 WRX
Platinum Silver

Default

Yep, the dealer checked everything. Airbox seals, fuel pump and fuel filter, o2 sensor and MAF sensor. Everything was in order. I talked to the mechanic and he was cool. Told him I had the COBB Stage1 and he told me to uninstall it and run stock map for a while and see if it comes up again. Which I doubt it will. Everything that could cause that CEL checked out fine except the ECU which he couldn't test. I will more than likely be selling my AccessPORT at this point.

19200ish - installed AccessPORT
19800ish - CEL
20 miles later - uninstalled AccessPORT
readymix is offline  
Old 05-05-2004, 01:12 AM   #15
CirrusWRX
Scooby Guru
 
Member#: 17439
Join Date: Apr 2002
Chapter/Region: Tri-State
Location: Yardley, PA
Vehicle:
2002 x2 Silver WRX
Sedan, White WRX Wagon

Default

...very interesting....
CirrusWRX is offline  
Old 05-05-2004, 02:21 AM   #16
LTSmash
Scooby Newbie
 
Member#: 32010
Join Date: Jan 2003
Location: so cal
Vehicle:
2006 Legacy GT Wagon
White

Default

readymix,

i appreciate you reporting your findings. i believe we have a 30-day satisfaction guarantee period with cobb. i guess i'll give them a call later this week to find out what their return policy is.

that sputtering at idle stopped once you uninstalled AP, right?
LTSmash is offline  
Old 05-05-2004, 11:37 AM   #17
CirrusWRX
Scooby Guru
 
Member#: 17439
Join Date: Apr 2002
Chapter/Region: Tri-State
Location: Yardley, PA
Vehicle:
2002 x2 Silver WRX
Sedan, White WRX Wagon

Default

For both of you guys - I totally support your decision whatever it is, but please, for the sake of the rest of the community, GIVE THEM A CALL!!!

I think you are totally in the right to get your money back, especially if there is a potential problem with your cars and the AP. I think you guys are clearly in the minority, but I think it's only fair to everybody to call Cobb and see what's up- Maybe you ended up with the wrong version of the AP. Maybe they'll tell you to download a new map. Maybe they'll tell you to send them your ECU. Maybe they'll ask you to try something else.

Bottom line, they'll probably try and help you sort it out, and you have the absolute right to refuse anything they ask and just get your money back. But either way, at least give yourself the option, and report it to them so they can log it for future reference.

EDIT: Made a post on the cobb forums where you started your thread LT, and addressed a quick ? to readymix

Last edited by CirrusWRX; 05-05-2004 at 12:21 PM.
CirrusWRX is offline  
Old 05-06-2004, 12:02 AM   #18
LTSmash
Scooby Newbie
 
Member#: 32010
Join Date: Jan 2003
Location: so cal
Vehicle:
2006 Legacy GT Wagon
White

Default

cirrus,

i've been out doing field work all day...so i haven't had the chance to do anything. i tried calling cobb yesterday during my lunch hour (12-1pm pdt), but kept getting their voicemail. apparently no one's around during their lunch time. i didn't leave a message cause i don't have much privacy in my cube (boss and division head are within earshot), so i'd have to call in when they're both occupied in a meeting or something. anyway, i do intend to give them a call.
LTSmash is offline  
Old 05-06-2004, 03:18 AM   #19
LTSmash
Scooby Newbie
 
Member#: 32010
Join Date: Jan 2003
Location: so cal
Vehicle:
2006 Legacy GT Wagon
White

Default

my latest update on the cobb forums:

Quote:
let me first state that i never said that cobb's AP was absolutely the cause for our problem.

please put yourself in readymix and my shoes for a minute. this is my ~90mi daily driver and i cannot afford to be without it for even one day (this seems to be the case for readymix too), so this explains why we've been extra cautious in this situation. i am an engineer as well, and when the CEL first came on, my first instinct was the same as readymix's: since i've never had this problem in the 37k miles prior to my recent catback and AP installation, it is likely one of these new components introduced to the system is the cause. because i am by no means an experienced tuner or automotive tech, i went to the nasioc boards for advice. granted, i did not check all the possible hardware causes as suggested by fellow nasioc members; however, when another member comes up with the same problem, has a different MY and mileage, and similar recent mods, i couldn't help not to question the cobb reflash. especially since we don't have access to their loop and logic, and when we both uninstalled AP our problems appeared to go away (please note these events i am describing was before Trey's explaination of cobb's a/f ratio loops).

ok, that being said...i finally got around to inspecting more hardware. i inspected my MAF sensor tonight. the mass flow sensors were clean, but the temperature sensor was dirty. i'm thinking that this was my problem now. since the actual flow will vary with temperature, the air temperature reading is essential. this is my somewhat educated assumption to the A/F ratio loop (Trey or someone else please correct me if i am wrong):

1. the ECU gets the air flow (Q) and air temp (T, in absolute temp units) from the MAF sensor
2. the ECU corrects Q to flow in standard temp, i.e. Qx(standard abs temp/T)
3. the ECU can now use the corrected flow reading to obtain its target A/F ratio

thus, in my case...dirty temp sensor -> inaccurate temp reading -> wrong flow correction factor -> engine running too lean. also, the recent heat wave in so cal may have finally pushed the incorrect temp reading past its tolerance. at the moment, this is what i'm concluding as the cause for my CEL....readymix obviously has a different cause for his CEL.

Trey - thanks for enlightening us about the AP A/F ratio loops
LTSmash is offline  
Old 05-08-2004, 09:41 AM   #20
uptownWRX
Scooby Newbie
 
Member#: 34289
Join Date: Mar 2003
Vehicle:
2004 STi
Aspen White

Default

I have gotten this same code. Point in fact I just got it again this morning on the way to work.

Here is what I have. 04STi, TBE exhaust and that is all.

This is the situation in which the CEL came on this morning. 65ish degree's outside, and in a hurry to get to work. I was on the car hard and in the top of fifth gear (100+ MPH) and the car studdered and the CEL came on along with the flashing cruise light.

I have read the post that CirrusWRX wrote about checking all the connections and I will be doing that tomorrow to make sure everything is tight. But is there any chance that the rear O2 sensor could have an effect on this CEL?

We did have to remove the top mount and there is a chance there is something loose, there always is a chance. But I did not ever have this code come on untill I put a downpipe on. And the top mount has been off more than once.

:edit: I did not port the wastegate and i am not sure what the boost levels are.

I suppose it would help if I got a gauge to see if there is something going on boost wise. Would fuel cut cause this CEl or to much boost? Just throwing out idea's. :edit:

Last edited by uptownWRX; 05-08-2004 at 09:55 AM.
uptownWRX is offline  
Old 05-08-2004, 10:50 AM   #21
CirrusWRX
Scooby Guru
 
Member#: 17439
Join Date: Apr 2002
Chapter/Region: Tri-State
Location: Yardley, PA
Vehicle:
2002 x2 Silver WRX
Sedan, White WRX Wagon

Default

uptown- I apologize, but I'm just not familiar with the STi in terms of what types of "differences" it has, but for everybody else that I'VE spoken to about the p0171, the car really didn't exhibit odd behavior. You noted a studder and flashing cruise light; nobody else that I've read about had anything other than the light turn on while cruising, and then perhaps a very low-mileage tank of gas.

When you say "top mount" you mean intercooler, right? In that case, that is probably the #1 place to check for loose/missing/misrouted hoses+lines. Again, my knowledge of the STi is so limited, take it with a grain of salt, but I have yet to ever see a coincidence between the REAR o2 sensor and the p0171.

Unfortunately, it will be necessary to get a boost gauge (of some form) to monitor your boost with the new TB, and your thinking about possible fuel cut might explain it.

My advice: RECHECK all the hoses with a buddy, or maybe an STi side by side, and have somebody double-check your work. Make sure your DP isn't leaking anywhere (thought that'd really have nothing to do with your code...), and then I'd post this in the 2.5L forum since they'll be of more help.

g/l!
CirrusWRX is offline  
Old 05-08-2004, 12:04 PM   #22
WRXBob
Scooby Specialist
 
Member#: 12455
Join Date: Nov 2001
Location: CA
Vehicle:
02 WRX

Default

Quote:
Originally posted by uptownWRX
I have gotten this same code. Point in fact I just got it again this morning on the way to work.

Here is what I have. 04STi, TBE exhaust and that is all.

This is the situation in which the CEL came on this morning. 65ish degree's outside, and in a hurry to get to work. I was on the car hard and in the top of fifth gear (100+ MPH) and the car studdered and the CEL came on along with the flashing cruise light.

I have read the post that CirrusWRX wrote about checking all the connections and I will be doing that tomorrow to make sure everything is tight. But is there any chance that the rear O2 sensor could have an effect on this CEL?

We did have to remove the top mount and there is a chance there is something loose, there always is a chance. But I did not ever have this code come on untill I put a downpipe on. And the top mount has been off more than once.

:edit: I did not port the wastegate and i am not sure what the boost levels are.

I suppose it would help if I got a gauge to see if there is something going on boost wise. Would fuel cut cause this CEl or to much boost? Just throwing out idea's. :edit:

You better make sure what kind of boost pressure you are running. You may be running too much boost and trigger this code.
WRXBob is offline  
Old 05-19-2004, 04:11 PM   #23
CirrusWRX
Scooby Guru
 
Member#: 17439
Join Date: Apr 2002
Chapter/Region: Tri-State
Location: Yardley, PA
Vehicle:
2002 x2 Silver WRX
Sedan, White WRX Wagon

Default

any updates on this??
CirrusWRX is offline  
Old 06-01-2009, 09:31 AM   #24
postysti
Scooby Newbie
 
Member#: 201242
Join Date: Jan 2009
Chapter/Region: Tri-State
Location: NJ
Vehicle:
05 STi

Default

Cleaning the MAF sensor, could be dirty, would help
postysti is offline  
Old 06-01-2009, 09:37 AM   #25
012.5RS
Scooby Newbie
 
Member#: 95051
Join Date: Sep 2005
Chapter/Region: Tri-State
Location: PA
Vehicle:
02 WRX Wagon
World Rally Blue

Default

I had the same prob with mine. pulled and cleaned maf, it was filthy and now code is gone.
012.5RS is offline  
Closed Thread

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

Similar Threads
Thread Thread Starter Forum Replies Last Post
cel code p0171 system too lean ( bank 1) gillyfesh7 Factory 2.0L Turbo Powertrain (EJ Series Factory 2.0L Turbo) 13 09-01-2008 11:59 AM
P0171 System Too Lean (Bank 1) polish_lukasz Service & Maintenance 5 04-16-2008 12:30 PM
DTC P0171 System Too Lean (Bank 1)? RickDaTuner Factory 2.5L Turbo Powertrain (EJ Series Factory 2.5L Turbo) 3 12-11-2006 01:47 PM
02 wrx P0171 system too lean innuendo Factory 2.0L Turbo Powertrain (EJ Series Factory 2.0L Turbo) 3 05-07-2006 08:15 PM
System Too Lean Revisted: P0171 CEL Hank3 Factory 2.0L Turbo Powertrain (EJ Series Factory 2.0L Turbo) 12 11-11-2002 12:05 AM

All times are GMT -4. The time now is 02:09 PM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2018 Axivo Inc.
Copyright ©1999 - 2017, North American Subaru Impreza Owners Club, Inc.