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Old 09-07-2012, 11:04 AM   #1
Millhouse_5
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Member#: 269208
Join Date: Jan 2011
Chapter/Region: E. Canada
Location: Nova Scotia
Vehicle:
95 JDM STI RA
08 2.5i Sedan

Default cold start issues

Ive been having this issue since the day i bought my car.
20g with 115km on it

Whenever i go to start my car from cold (eg. more than 4 hours off or so) it turns over and sputters around 250 rpm for anywhere from 1 to 10 seconds and then just stalls.
I usually let it sit for about 5 seconds after it stalls and then try again. It starts perfectly. no issues, no long time cranking, just perfect.

and every now and then within the first 2 minutes or so of running it stutters a little bit when under very low load. like cruising in 4th around town on a flat road. give it a little gas and the sputter disappears.

once its warm though all of thest issues disappear. within 5 minutes of a cold start its all perfect again, starting and all.

any ideas what could be going on here. I'm thinking its a fuel system issue like filter or something but ive yet to do any active troubleshooting.
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Old 09-07-2012, 12:34 PM   #2
TommyAtomic
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Location: Vancouver BC
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1993 JDM WRX Wagon
Black

Default

So many possibilities, Here's a few to look at:

Plugs or Coilpacks especially if it has the JDM EJ20G coilpacks instead of the coilpack upgrade.
Bad Coolant temp sensor; effects coldstart and idle.
Epic filth in the coolant line running into your IACV; Remove lines and use brakecleaner to clean that the crap out of the line. It uses a sensor as well and when clogged with garbage it will effect coldstart and idle.

Weak signal from the Crank position sensor. effects startup. Test by removing and cleaning sensor if it gets better you know that the sensor is weak. Replace it.
Weak pressure from a bad fpr; what is your actual fuel pressure at startup?
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Old 09-07-2012, 04:50 PM   #3
Millhouse_5
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Join Date: Jan 2011
Chapter/Region: E. Canada
Location: Nova Scotia
Vehicle:
95 JDM STI RA
08 2.5i Sedan

Default

Coilpacks - as far as i know, yes they are the stock coils. what way would i check though to be sure.

Coolant temp sensor - wouldn't i notice this while running too? The gauge still works fine, there's no sporadic behavior at all. Heats up slowly and stays steady

Epic Filth - Possible, I'll see if i can clean it out.

Crank position - Not a clue

FPR - i don't have a gauge so i have no idea what my pressure is
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Old 09-07-2012, 07:08 PM   #4
TommyAtomic
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Default

Quote:
Originally Posted by Millhouse_5 View Post
Coilpacks - as far as i know, yes they are the stock coils. what way would i check though to be sure.
If its a 95 jdm and you are the one that imported it then its definitely stock. Look at the coilpack upgrade stickied at the top of the threadlist

Quote:
Originally Posted by Millhouse_5 View Post
Coolant temp sensor - wouldn't i notice this while running too? The gauge still works fine, there's no sporadic behavior at all. Heats up slowly and stays steady
The sensor for the dash temp guage and the coolant temp sensor are completely seperate. Ironically they plug in right next to each other and are equally a PITA to get at or get out..

Quote:
Originally Posted by Millhouse_5 View Post
Crank position - Not a clue
Not the crank position itself; The crank position sensor. unplug it. unbolt it. clean it. put it back and plug it in. if the problem is better after cleaning then the signal was weak. replace it.
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Old 09-07-2012, 07:48 PM   #5
Millhouse_5
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08 2.5i Sedan

Default

Thanks, this should help out a lot when i got to troubleshoot it myself.
But, no i was not the one who imported the car, and i was abreviating when i just said crank position. if that were wrong i think i would notice a little more than cold start issues, lol.

thanks again man
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Old 09-07-2012, 09:48 PM   #6
stihammer998
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I had this problem let me know if you find a solution. Thanks
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Old 09-08-2012, 12:03 AM   #7
Millhouse_5
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08 2.5i Sedan

Default

well I'm more looking for ideas and things i can try over the winter. right now i'm out of province and the car is back home. the only time i have off before the snow comes down is at the beginning of October and i doubt I'll have enough free time to start taking my car apart to diagnose this odd problem.

I mostly like to gather information to an abnormal extent before i set off on any project. That way i know what could be the problem and why the fix I'm trying may work. But I will post up an answer if i find out what it is.
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Old 09-09-2012, 07:59 PM   #8
69subaru360
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1998 2.5 RS

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Mine had this issue. After I upgraded to bigger injectors and a walbro fuel pump it went away. I'm inclined to think it was one of them bleeding down fuel pressure.
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Old 09-10-2012, 08:42 PM   #9
Millhouse_5
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95 JDM STI RA
08 2.5i Sedan

Default

If only i had a fuel pressure gauge, lol. Then i could diagnose that one easily
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Old 09-10-2012, 08:47 PM   #10
69subaru360
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1998 2.5 RS

Default

Quote:
Originally Posted by Millhouse_5 View Post
If only i had a fuel pressure gauge, lol. Then i could diagnose that one easily
Turn the key on, listen to the fuel pump prime. When it stops key off, wait a minute and repeat, then crank. If it starts up its a fuel issure
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Old 09-10-2012, 09:04 PM   #11
Millhouse_5
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Member#: 269208
Join Date: Jan 2011
Chapter/Region: E. Canada
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Vehicle:
95 JDM STI RA
08 2.5i Sedan

Default

Tried it tons of times, guess its not a fuel issue.
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Old 09-10-2012, 09:29 PM   #12
wrxstijdm
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1998 V4 Impreza STI
EJ20K engine

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Is this what happens to you?


If so, I was not able to find a solution... I learned to live with it and just consider it as one of those "Subaru things"...
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Old 09-11-2012, 09:59 PM   #13
jdmwrx94
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red

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Installed 550 injectors and it fixed my cold start issue. Had A broken rubber, 1 injector had a broken plastic tip and snother didnt even had a plastic tip...
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