misfiring/random CELs
#1
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Thread Starter
iTrader: (14)
Join Date: Mar 2004
Location: east bay, ca
Posts: 652
Car Info: 04 sti / 02 wrx / 01 cbr600 f4i
misfiring/random CELs
i just wanted to post this to see if anyone else has had the same or similar problem in the past. first, the setup:
2002 wrx 2.0 120k miles on the motor
approx 50k miles with the following setup:
vf39, sti pink injectors, walbro, tmic
AP tuned
the problem:
the car ran fine with the above mods for about 3 years, but recently has started throwing CELs and having a very rough idle. the first time it threw the code, i was driving the car normally with a broken b pipe (part between the axel back and downpipe) so i got it welded (good work), but that didn't solve the problem
i pulled the code with my AP and i usually get a p0302 with a p0300, but if i drive the car longer with the CEL on, i will get a p0301, p0303, and/or a p0304.
the weird thing is that the car will idle fine at first, but once it warms up you can hear the misfiring in the exhaust note. it will only throw the light during local driving, but i can drive it on the freeway for very long distances and it won't throw the light until i slow down to city driving speeds. it hasn't thrown the lights at idle
while driving the car, whether the CEL is on or not, i can feel a slight hesitation during acceleration. the throttle becomes smooth again once at speed.
what i've tried:
-changed all the spark plugs, and didn't solve the problem
-switched around all the coil packs to see if one was faulty, and the problem continued
-checked pretty much all vacuum and boost lines and they seem fine
-removed the MAF sensor and cleaned it with MAF cleaner
so i need advice. my best guess right now is that the MAF sensor has gone bad. i also have a suspicion that it could be the timing belt. any other suggestions anyone? any help would be much appreciated.
thanks,
marc
2002 wrx 2.0 120k miles on the motor
approx 50k miles with the following setup:
vf39, sti pink injectors, walbro, tmic
AP tuned
the problem:
the car ran fine with the above mods for about 3 years, but recently has started throwing CELs and having a very rough idle. the first time it threw the code, i was driving the car normally with a broken b pipe (part between the axel back and downpipe) so i got it welded (good work), but that didn't solve the problem
i pulled the code with my AP and i usually get a p0302 with a p0300, but if i drive the car longer with the CEL on, i will get a p0301, p0303, and/or a p0304.
the weird thing is that the car will idle fine at first, but once it warms up you can hear the misfiring in the exhaust note. it will only throw the light during local driving, but i can drive it on the freeway for very long distances and it won't throw the light until i slow down to city driving speeds. it hasn't thrown the lights at idle
while driving the car, whether the CEL is on or not, i can feel a slight hesitation during acceleration. the throttle becomes smooth again once at speed.
what i've tried:
-changed all the spark plugs, and didn't solve the problem
-switched around all the coil packs to see if one was faulty, and the problem continued
-checked pretty much all vacuum and boost lines and they seem fine
-removed the MAF sensor and cleaned it with MAF cleaner
so i need advice. my best guess right now is that the MAF sensor has gone bad. i also have a suspicion that it could be the timing belt. any other suggestions anyone? any help would be much appreciated.
thanks,
marc
Last edited by diz; 10-05-2008 at 01:06 AM.
#2
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Join Date: Feb 2008
Location: Ventura, CA
Posts: 193
Car Info: 04 EJ207 6mt WRX, 08 Spec B
Yea a buddy of mine had the same symptoms, miss firing, etc. it ended up that he skipped three teeth on his timing, and had a cracked cam gear! So the timing belt diagnosis could be correct.
#7
Registered User
Thread Starter
iTrader: (14)
Join Date: Mar 2004
Location: east bay, ca
Posts: 652
Car Info: 04 sti / 02 wrx / 01 cbr600 f4i
took it to AutoHQ to get the timing belt done, and that didn't solve it although the car drives considerably better. alex did suggest that i might need a valve adjustment. i haven't checked the clearances but i'm considering getting the adjustment done anyway
#8
you having compression problems do an cylinder leak down test(do it on an hot engine and cold) most likly piston rings and valves. Does it smoke and i down mean black smoke blueish or white/blue. Do u add oil etc?
Last edited by Konrad_WRC; 12-13-2008 at 02:21 PM.
#10
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iTrader: (12)
i have the same issue..same setup....I remember when i installed AP on stage one and got the same codes..but when i uninstalled it...the CEL never turned on..When i went on to Stage 3 with vf39..i used the AP and then got it protuned and it still does it..so i don't whats going on..no problems but the CEL..
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