Go Back   Subaru Impreza Forum - WRX STI Rally Performance Tuning > Subaru Impreza Technical Area > Engine Bay

Subaru Impreza Forum

guess the sensor issue time!
LinkBack Thread Tools Display Modes
Old 07 Jun 2013, 08:04 PM   #1 (permalink)
Fresh Scooby
Join Date: Feb 2013
Posts: 3
guess the sensor issue time!

hey kids! LONG time lurker, years in fact.. I have an issue now that I can't solve.

02' WRX stage 3 COBB, VF34, OS MAF. ect. no problems in over 150k Km then one day in early winter car just went to shite..

Picked up a massive misfire across all cylinders, changed plugs and misfires reduced but stayed, coils checked out, sea foamed internally and through fuel.. after a few months of driving and paying close attention to the car I've narrowed it down;

Open loop is fine call it 90% ( out of a possible perfect 100% where the engine is working at optimal), my gas mileage is more then double in open loop and I don't get any misfires/flashing CEL.
Cold start acceleration and enrichment seems to be 'good' not perfect call it 70%.. where the problem lies is in closed loop- engine warm" ~30% drive-ability.
Tip in bogs down, back fires during static load & load situations, plus popping concurrent with over fueling and of course SHITE mileage, were talking 1/4 tank or more usage in under 30 miles.

So my question is, which sensors should I be looking at as the primary cause. I DO have a C-west hood that has open venting right over the MAF sensor, I've cleaned the element with no joy.

Thanks in advance guys.
Offline   Reply With Quote
Old 08 Jun 2013, 06:37 AM   #2 (permalink)
Veteran Scooby
bugeye_bob's Avatar
Join Date: Mar 2009
Location: UK-Earth - Search google maps for "The Stig"
Posts: 4,563
Re: guess the sensor issue time!

Nps checked ?
-- .. ... ... .. -. --. / -... ..- - / -. --- - / ..-. --- .-. --. --- - - . -.
Offline   Reply With Quote
Old 09 Jun 2013, 12:39 AM   #3 (permalink)
Fresh Scooby
Join Date: Feb 2013
Posts: 3
Re: guess the sensor issue time!

didn't think of that, is there a non shop based way to check it.. besides replacing it ?
Offline   Reply With Quote
Old 09 Jun 2013, 05:34 PM   #4 (permalink)
Cool Scooby
Technical_Bob's Avatar
Join Date: Feb 2010
Location: In a cloud up in the sky, Like lucy
Posts: 291
Send a message via MSN to Technical_Bob
Re: guess the sensor issue time!

cheap OBD lead and laptop
Subaru servicing, repairs and diagnostic fault finding help available.
Offline   Reply With Quote
Old 10 Jun 2013, 04:21 PM   #5 (permalink)
Fresh Scooby
Join Date: Feb 2013
Posts: 3
Re: guess the sensor issue time!

Idle is lumpy and missing as well, so i don't think it's the NPS. Really it sounds like ass right now.

I'm going to replace in order: intake press sensor, MAF, tps, NPS. since it runs fine in open loop I may just adjust out closed loop and run full open loop..

anyone done a full rpm open loop ? downfalls? drawbacks?
Offline   Reply With Quote


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
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
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Best guess please ... joebucks Technical General 2 07 Feb 2010 05:32 PM
Bet You Cant Guess This One..... mikepic Technical General 5 25 Apr 2006 06:13 PM
Guess the cost time mr freeze Spam Bin (Does exactly what it says on the tin) 23 22 Apr 2006 05:02 PM
Well, here goes I guess... Phill-type-R Users Photo Gallery 48 16 Aug 2005 09:43 PM
Guess what! ScoobywagonGL General Chat - Anything about Anything 11 08 Jul 2004 09:43 PM

All times are GMT. The time now is 09:33 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
LinkBacks Enabled by vBSEO 3.6.0 PL2 © 2011, Crawlability, Inc.