Welcome to the North American Subaru Impreza Owners Club Monday July 28, 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 03-20-2010, 06:30 AM   #1
DinoGuan
Scooby Specialist
 
Member#: 42233
Join Date: Aug 2003
Chapter/Region: SCIC
Location: San Diego
Vehicle:
04 WRX waGGon
WRB

Default (Halp!) Engine cutout & dies intermittently along with hot start issue

This one has me pretty stumped.

So it started a few months ago as a hot start issue.
After warming the car up, driving, stopping, and letting it sit for 45minutes to an hour, it would not fire at all. This will last for anywhere from 5 seconds to 10 minutes! It is simply remedied with time.
Of course this issue did not happen every single time, it would occur maybe 50% of the time when I hit that exact time window.
*It fires up perfectly when cold*

Now all of a sudden, when I am trying to accelerate I will randomly get a knock signal from my utec, immediately followed by the engine cutting out and dying completely. No power what so ever, unless I depress the gas pedal past ~75%. Then it will give me some power, but its not much. It bucks and pops out the exhaust and generally doesnt sound good, and will usually eventually stop giving me power until I release the pedal and depress it again past 75% throttle.
I have to hope I have enough momentum to coast off the street into a parking lot where it will refuse to start for about 30 seconds to a minute. Then it will fire right up, and run perfectly fine.

However this last time, and it has only done this once. After it stalled and died on the road. I was able to fire it up, but it would not stay running. I could hold the throttle open past 75% again to get it to sputter for a few seconds before dying completely.

I'm so stumped.

The Car:
04 WRX Wagon
85k miles
UTEC (Open Loop Mode)
VF30
Deatschwerks 750cc
Walbro 255
Ebay TMIC
Catless


I would greatly appreciate any idea you guys might have.

Here have been my best guesses.

Coolant Temp Sensor: Explains the Hot Start Issue, but does not explain the stalling and dying.

Crank Sensor: Possibly faulty after sitting, explaining the hot start issue, knock causes the sensor to fault, causing the stalling. But does not explain why depressing the throttle past 75% will cause it to run. Or why simply sitting and waiting will fix it.

Fuel Pressure Regulator: Heat soak causes it to fault and prevents starting. Knock and high manifold pressure causes it to fault and the car to stall and die. Does not explain why depressing the throttle past 75% will allow it to sputter for a few seconds....


What is wrong with my baby???
* Registered users of the site do not see these ads.

Last edited by DinoGuan; 03-20-2010 at 08:17 PM.
DinoGuan is offline   Reply With Quote
Old 03-20-2010, 12:57 PM   #2
Subey03
Scooby Specialist
 
Member#: 159909
Join Date: Sep 2007
Chapter/Region: BAIC
Location: Arkansas Little rock..current
Vehicle:
2004 STI on AIR
PSM

Default

long shot but ecu maybe dieing..or ecu wires frayed some where...

man low miles and these problems gl....keep updated
Subey03 is offline   Reply With Quote
Old 03-20-2010, 01:30 PM   #3
Flyin_Hayn
Scooby Specialist
 
Member#: 175031
Join Date: Mar 2008
Chapter/Region: NWIC
Location: Sauce Town, OR
Vehicle:
2005 PSM STi
Stage2 303awhp / 331awtq

Default

I would swap your ecu at this point, reflash with utek see if it helps. The car runs normal at times so that is good, its in reach
Flyin_Hayn is offline   Reply With Quote
Old 03-20-2010, 08:21 PM   #4
DinoGuan
Scooby Specialist
 
Member#: 42233
Join Date: Aug 2003
Chapter/Region: SCIC
Location: San Diego
Vehicle:
04 WRX waGGon
WRB

Default

Hmmmm. Since a spare ECU is not exactly cheap. Could you guys think of any ways to diagnose if there is a problem with the ECU?

I had my UTEC connected one time when it wouldn't start after dinner. And all the sensors and signals came in fine.
I noticed there was no rpm signal when I am cranking it. But then when it starts fine there is no rpm signal either. *shrug*
DinoGuan is offline   Reply With Quote
Old 03-21-2010, 11:27 PM   #5
Haelan
Scooby Specialist
 
Member#: 151045
Join Date: Jun 2007
Location: NW Indiana
Vehicle:
2013 Subaru STI
CBP

Default

Quote:
Originally Posted by DinoGuan View Post
I noticed there was no rpm signal when I am cranking it. But then when it starts fine there is no rpm signal either. *shrug*
That points to the crank position sensor, which provides your RPM feedback. It's either the CPS, the wiring, or the ECU itself. You can grab a used CPS in the for sale section for a few bucks. A wire verification doesn't take too long. Some member have reported one of the CPS wires pulling right out of the harness plug so that might be a good spot to check.

Have you scanned for any pending codes in the ECU?
Haelan is offline   Reply With Quote
Old 03-30-2010, 06:30 PM   #6
DinoGuan
Scooby Specialist
 
Member#: 42233
Join Date: Aug 2003
Chapter/Region: SCIC
Location: San Diego
Vehicle:
04 WRX waGGon
WRB

Default

Update:

Checked my CEL codes:
0335 - CPS Sensor A Circuit Malfunction
0301 - Misfire 1
0302 - Misfire 2
0303 - Misfire 3
0304 - Misfire 4

Replaced the CPS 5 days ago. Has not had hot start issue. However yesterday;
I was in 2nd gear, slight up-hill, 3.5krpm, put my foot down, boost built to near-peak, 17 or 18ish. And the car completely died again. This time however there was tons of blue smoke and the super strong smell of burning oil. The smoke appeared in a cloud right when the car died and kinda followed me as I pulled off the road. RPM signal seemed to be working as the tach was reading proper RPM's as I was coasting down in gear.
On the side of the road I tried to start it, nothing at first, and some more blue smoke. Then about 20 seconds later and a few more tries to start it, she fired right up and drove home perfectly fine.

I'm stumped. I'm going to try and re-create the problem tonight while data logging.
DinoGuan 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
Hot start issue Desibabu345 Factory 2.0L Turbo Powertrain 5 12-03-2008 07:25 PM
Think this may have had something to do with my starting issues? IronMonkeyL255 South East Region Forum 12 08-25-2006 11:19 AM
96 Legacy 2.2 hot start issues b1pig Normally Aspirated Powertrain 0 06-28-2006 08:41 PM
hot start issue. supermoose Subaru Conversions 2 12-16-2003 12:32 PM
hot start issue with ignition supermoose Service & Maintenance 7 12-16-2003 02:11 AM


All times are GMT -4. The time now is 09:34 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.