Welcome to the North American Subaru Impreza Owners Club Saturday April 19, 2014
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC Technical > Factory 2.0L Turbo Powertrain

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 09-04-2008, 02:18 PM   #1
Rodwrx23
Scooby Specialist
 
Member#: 170948
Join Date: Feb 2008
Chapter/Region: South East
Location: Pembroke Pines, FL
Default ECU gone bad? Car still run through UTEC?

So I've been having problems with my beloved bugeye for a little more than a week or so. It all stared with the speedo needle jumping around. I then started getting misfire codes even after installing brand new properly gapped plugs and my front 02 is fairly new with only 10K miles on it. The car is idling all over the place and my AFR is everywhere too. The car started running really crappy so after searching these symptoms I decided to swap out my alternator since I've been having voltage issues for a while now (going down to 11.6V under full load at idle.) The new 140A did not help at all.

Today i decided to try a troubleshooting experiment and I unplugged my UTEC harness from the ecu and connected the factory harness to the factory ecu, essentially bypassing the UTEC to see if it was a UTEC issue. The car would not start at all, just kept cranking and cranking. The second I reverted back to normal UTEC operation, the car started right up. I've checked my fuses and grounds and can't seem to find any burnt. I don't have a dmm to check them more thoroughly.

I'm kind of at a loss of what else to do to fix my daily driver. I'm going to ask and see if someone in my local regional forum will let me try their stock ecu just to test it out before spending $$$ on a replacement ecu. Any help to get this figured out will be greatly appreciated.

Rodrigo
* Registered users of the site do not see these ads.
Rodwrx23 is offline   Reply With Quote
Old 09-04-2008, 02:20 PM   #2
recce02
Scooby Specialist
 
Member#: 13815
Join Date: Jan 2002
Chapter/Region: SCIC
Location: Good ol Temecula
Vehicle:
02 GCRally prepped
277TQ 281HP 19PSI

Default

Careful in borrowing an ECU. You may have a short somewhere that may destroy the borrowed one. Assuming that there is a short anywhere which it sounds like.
recce02 is offline   Reply With Quote
Old 09-04-2008, 02:55 PM   #3
Rodwrx23
Scooby Specialist
 
Member#: 170948
Join Date: Feb 2008
Chapter/Region: South East
Location: Pembroke Pines, FL
Default

So do you think mine is done then?
Rodwrx23 is offline   Reply With Quote
Old 09-04-2008, 03:20 PM   #4
mxpunk
Scooby Specialist
 
Member#: 132130
Join Date: Nov 2006
Chapter/Region: TXIC
Location: Austin, Texas
Vehicle:
2002 Ford F-150
Graphite Gray

Default

whats your engine setup? is your current ecu flashed?
mxpunk is offline   Reply With Quote
Old 09-04-2008, 07:33 PM   #5
Rodwrx23
Scooby Specialist
 
Member#: 170948
Join Date: Feb 2008
Chapter/Region: South East
Location: Pembroke Pines, FL
Default

Engine:

Stock motor
PE 650cc injectors
Perrin fuel rails
Walbro 255lph fel pump
APS SR40 turbo
Turbo XS UP and TB
UTEC
P&L Hi-Flo intake
Turbo XS FMIC
stock BPV

When I got tuned back in April, the guy said he only used Opensource to raise my idle a hair and dial in the injectors, everything else was done through the UTEC. This was the first time the stock ecu has ever been touched.

As far as my ECU experiment goes, what does it mean if my car wouldn't start at all just using the stock ecu but it started with the UTEC connected?

Last edited by Rodwrx23; 09-04-2008 at 07:48 PM.
Rodwrx23 is offline   Reply With Quote
Old 09-05-2008, 12:11 PM   #6
Rodwrx23
Scooby Specialist
 
Member#: 170948
Join Date: Feb 2008
Chapter/Region: South East
Location: Pembroke Pines, FL
Default

bump for some help please
Rodwrx23 is offline   Reply With Quote
Old 09-05-2008, 12:17 PM   #7
b00steddueceduece
Scooby Newbie
 
Member#: 178057
Join Date: Apr 2008
Default

have your coil packs tested, or pull your spark plugs out, if one looks like its saturated with fuel, its not firing, so probably a bad coil, just my .02, its worth at try. Having a bad coil pack will obviously make the ecu throw a misfire code and also cause the car to idle rich and low, low rpm will make a drop in voltage at idle. As far as not having the utec pluged in, your stock ecu probabley isn't calibrated for those bigger injectors so its probably dumping way to much fuel in during startup with the utec unpluged.
b00steddueceduece is offline   Reply With Quote
Old 09-05-2008, 12:28 PM   #8
mxpunk
Scooby Specialist
 
Member#: 132130
Join Date: Nov 2006
Chapter/Region: TXIC
Location: Austin, Texas
Vehicle:
2002 Ford F-150
Graphite Gray

Default

Quote:
Originally Posted by b00steddueceduece View Post
have your coil packs tested, or pull your spark plugs out, if one looks like its saturated with fuel, its not firing, so probably a bad coil, just my .02, its worth at try. Having a bad coil pack will obviously make the ecu throw a misfire code and also cause the car to idle rich and low, low rpm will make a drop in voltage at idle. As far as not having the utec pluged in, your stock ecu probabley isn't calibrated for those bigger injectors so its probably dumping way to much fuel in during startup with the utec unpluged.
they are thoguh..thats why i asked. the ecu handles the stock injectors, while the UTEC just uses the headroom to add fuel
mxpunk is offline   Reply With Quote
Old 09-05-2008, 01:01 PM   #9
Cocoa Beach Bum
Scooby Specialist
 
Member#: 17355
Join Date: Apr 2002
Default

Quote:
Originally Posted by Rodwrx23 View Post
As far as my ECU experiment goes, what does it mean if my car wouldn't start at all just using the stock ecu but it started with the UTEC connected?
It means you have a connector/wiring issue. Even when the UTEC is connected, the OEM ECU handles all ignition and fueling associated with starting and idling.
Cocoa Beach Bum is offline   Reply With Quote
Old 09-05-2008, 01:18 PM   #10
Rodwrx23
Scooby Specialist
 
Member#: 170948
Join Date: Feb 2008
Chapter/Region: South East
Location: Pembroke Pines, FL
Default

Thanks guys. As far as my coilpacks go, I don't think all 4 have gone bad (2 have less than 15K miles on them) and my plugs have about 500 miles on them. I checked all my fuses in the engine compartment last night with a circuite tester and all lit up fine. I borrowed a dmm from a co-worker today so I guess I'll start looking around the ecu. I'm pretty sure I've got a charging issue too because I shouldn't see my voltage dropping to 11.6v under ful load at idle, especially with a brand new 140A alternator.

I really appreciate the feedback and help guys.
Rodwrx23 is offline   Reply With Quote
Old 09-05-2008, 04:09 PM   #11
b00steddueceduece
Scooby Newbie
 
Member#: 178057
Join Date: Apr 2008
Default

Quote:
Originally Posted by mxpunk View Post
they are thoguh..thats why i asked. the ecu handles the stock injectors, while the UTEC just uses the headroom to add fuel
Ahh I see, it was worth a shot
b00steddueceduece is offline   Reply With Quote
Old 09-05-2008, 04:10 PM   #12
b00steddueceduece
Scooby Newbie
 
Member#: 178057
Join Date: Apr 2008
Default

Grounding issue of some kind???
b00steddueceduece is offline   Reply With Quote
Old 09-05-2008, 05:05 PM   #13
Rodwrx23
Scooby Specialist
 
Member#: 170948
Join Date: Feb 2008
Chapter/Region: South East
Location: Pembroke Pines, FL
Default

I've checked and cleaned my grounds. Earlier I swithced my UTEC crossover point to 0% and the car feels a lot better, but AFR's ares still way off. Between 3-4000 rpm I'm anywhere between 15.0-16.8 at WOT.
Rodwrx23 is offline   Reply With Quote
Old 09-05-2008, 07:32 PM   #14
BluScubi
Scooby Newbie
 
Member#: 162726
Join Date: Oct 2007
Chapter/Region: MAIC
Location: Land O' Speed cameras, MD
Vehicle:
2009 LGT
QSM

Default

Have you had your battery tested? If your battery is bad and can't properly accept a charge it can throw your charging system out of wack. Happened to me. I had a bad cell in the batt and the alternator was charging all over the place, as low as 8v and as high as 15v.

If the battery is good try doing a voltage drop test from the alternator output terminal to battery positive with car running. Should be no more than .5v. Also check resistance from alternator case to battery negative with engine off. Should be close to 0 ohms. I have no idea about the ECU and UTEC thing. Good luck.
BluScubi is offline   Reply With Quote
Old 09-05-2008, 08:32 PM   #15
Rodwrx23
Scooby Specialist
 
Member#: 170948
Join Date: Feb 2008
Chapter/Region: South East
Location: Pembroke Pines, FL
Default

Thank You All!


Quote:
Originally Posted by b00steddueceduece View Post
Grounding issue of some kind???
This tempted me to check my grounds again. The ground point on the driver side of the intake manifold is shared with a bracket for the charge pipe on my FMIC. I pressed down on it with the engine running and I could hear the engine surging a little. Relocated that ground right near there with its own point. Problem Solved!!! Took it for a spin and no jumpy speedo, no misfires, and car felt real solid again.



Quote:
Originally Posted by BluScubi View Post
Have you had your battery tested? If your battery is bad and can't properly accept a charge it can throw your charging system out of wack. Happened to me. I had a bad cell in the batt and the alternator was charging all over the place, as low as 8v and as high as 15v.

If the battery is good try doing a voltage drop test from the alternator output terminal to battery positive with car running. Should be no more than .5v. Also check resistance from alternator case to battery negative with engine off. Should be close to 0 ohms. I have no idea about the ECU and UTEC thing. Good luck.
I tested with the negative lead from the dmm to the battery - and the positive lead to the battery +. Then did it from the battery - to the alternator lead and I got identical readings. If ohms are the upside down horseshoes, then I have 0.2 from the battery - to the alternator case. (Laugh all you want but I have the electrical know how of a poodle with down syndrome.) I'm still getting voltage readings as low as 11.6 on my Apexi TT, and 12.28 on the dmm with AC on full blast and lights on at idle. I think I may add another big fat wire with maybe a 100A in line fuse from the alternator lead to battery + to see if that helps.

Thanks again guys! This happened just in time too because I had an appointment tomorrow morning to diagnose this thing, which would've cost me some much needed $$$. Now I can spend the day installing my EWG setup which has been sitting for more than 10 days while I've been trying to fix this issue. Please feel free to flame me all you want, I deserve it.
Rodrigo
Rodwrx23 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

Similar Threads
Thread Thread Starter Forum Replies Last Post
Car wont run with Utec... :( Rextion UTEC 14 09-02-2009 11:36 PM
ABS light, Tach to zero, yet car still runs lilo Mid Atlantic Impreza Club -- MAIC 2 08-05-2006 12:44 AM
Milk left out over night... still good, or gone bad? Hazdaz Off-Topic 25 06-04-2006 03:07 PM
ECU Gone Bad? White02WRX Engine Management & Tuning 4 08-11-2004 12:08 PM
ECU reset gone bad? Stickee Normally Aspirated Powertrain 3 06-10-2002 09:27 AM


All times are GMT -4. The time now is 06:25 PM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2014 Axivo Inc.
Copyright ©1999 - 2014, North American Subaru Impreza Owners Club, Inc.