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Old 04-18-2008, 02:51 PM   #1
afcivileng
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Unhappy P0303 code, misfire rough idle

Hi all, First things first I have
05 STi
Cobb Turboback exhaust
AEM shortram intake
Cobb accessport Stage 2
GFB Blowoff valve

A few months ago I drove my Sti through a huge puddle like 3 feet deep. Got the intake all wet. Car was starved of 02 and stalled. I got an MAF Flow high and all kinds of missfires. Dryed out the car it runs fine, now I am getting a p0303 code and really rough idle.

What should I DO.
Replace the sparkplugs
or the coil packs
or the wires
or the MAF
Or all of the above?

Thanks

Charles.
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Old 04-18-2008, 07:36 PM   #2
jaxscuby
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all of the above
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Old 07-02-2008, 06:10 PM   #3
afcivileng
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Ok I replaced the spark plugs, It fixed the problem for a little bit, but now the P0303 code keeps comming up. I switched out the coil packs, and still getting p0303, WTF.

What could be causing the misfire, if its not the plugs, not the coil packs, Then what is it?

Please Help

Thanks
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Old 07-02-2008, 07:00 PM   #4
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if your engine tried to hydrolock but didnt, quite

id look for vac leaks in the intake up to the turbo

do a compression check
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Old 07-02-2008, 08:15 PM   #5
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Start off by a doing a compression check. The water might have knocked out a ring land on one of your pistons.

Clark
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Old 07-04-2008, 06:25 PM   #6
afcivileng
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I also have a strong unburned fuel smell coming from my exhaust, What does thant mean?
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Old 07-04-2008, 06:38 PM   #7
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check the wires at 3rd cyl coil pack. Wiggle them and see what happens.
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Old 07-04-2008, 10:47 PM   #8
serdet
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you need to do what clark said above. too much water in an engine at one time is no good. I would bet the compression on #3 cylinder is low. good luck
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Old 07-06-2008, 12:22 PM   #9
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any news?
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Old 07-08-2008, 12:07 PM   #10
afcivileng
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Did the compression test here are the numbers:
cylinder 1: 135
cylinder 2: 135
cylinder 3: 141 ( the one with the misfire, Go figure highest compression)
cylinder 4: 138

So if its not a jacked up ring, could it be the injectors?
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Old 07-08-2008, 12:10 PM   #11
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Quote:
Originally Posted by afcivileng View Post
Did the compression test here are the numbers:
cylinder 1: 135
cylinder 2: 135
cylinder 3: 141 ( the one with the misfire, Go figure highest compression)
cylinder 4: 138

So if its not a jacked up ring, could it be the injectors?

How is your car running?
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Old 07-08-2008, 01:26 PM   #12
afcivileng
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It still idles rough, but I changed the base map on the ECU, went to stock mode, I think it helped, I didn't get the cel code when I came back from the shop. I'll keep driving it see if the code comes back.

I think I'll swap out the injectors for some 850 cc ones for good measure
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Old 07-08-2008, 01:28 PM   #13
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Maybe I missed it... but did you try swapping 1 and 3's coils around, seeing if the problem migrates?

-J
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Old 07-08-2008, 01:52 PM   #14
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might be in the valves(if your smelling fuel out the exhaust)
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Old 07-08-2008, 02:18 PM   #15
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Quote:
Originally Posted by AVANTI R5 View Post
might be in the valves(if your smelling fuel out the exhaust)
If he is actually misfiring in cylinder 3 that fuel isn't combusting and is going right out the tail pipe. Since he said the car is idling rougher I believe he is misfiring.
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Old 07-08-2008, 03:38 PM   #16
afcivileng
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Yeah I switched the coils around didn't change the misfire. the fuel smell might of come from the fact that I have a High Flow Cobb catt, and the misfire has messed up the catalyist.
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Old 07-08-2008, 03:39 PM   #17
afcivileng
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how could I check if it is a valve problem, is there a visual inpspection I can do or do I have to run some kind of diagnostic?
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Old 07-08-2008, 04:11 PM   #18
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Quote:
Originally Posted by afcivileng View Post
how could I check if it is a valve problem, is there a visual inpspection I can do or do I have to run some kind of diagnostic?
You would have to do a leak down test and if you are leaking then you could check and see if you can feel/hear it leaking out of the exhaust. IIRC 7% is the max for a stock motor.

-Rene
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Old 07-08-2008, 06:12 PM   #19
afcivileng
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Just had a thought, could it be my BOV. I have a GFB WRX Hybrid BOV Runing Half recerc and half Atm. Could that be making it too rich when I shift and then cause the misfire? I have had the BOV for years and had no problem with it.
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Old 07-09-2008, 01:06 PM   #20
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^^ get rid of it,esp. while trying to solve a misfire,
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Old 07-09-2008, 01:35 PM   #21
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Not to give you any scare but I have the same symptoms and ended up blowing a ringland. It seems you have ruled that out but who knows what it could be
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Old 07-09-2008, 07:18 PM   #22
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Quote:
Originally Posted by sts2689 View Post
Not to give you any scare but I have the same symptoms and ended up blowing a ringland. It seems you have ruled that out but who knows what it could be
Or you had a blown ringland leading to misfires in that cylinder(more likely)
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Old 07-09-2008, 09:59 PM   #23
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Hey man, it's Tim from morning muster with the black 04. I would put the stock BPV back on the car asap and take it for a drive on the stock map...see how it feels. The whole "drove through a puddle" thing sounds nasty and would really scare me, but if you have eliminated plugs, coils, and don't suspect the maf, then there's really only a few things it could be.

A leak down test would definitely eliminate the longblock as a source of the problems, assuming it tests normally. After that I would suspect an injector or something electrical that could have gotten wet.
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Old 07-09-2008, 11:49 PM   #24
afcivileng
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I went to full recerc on the bov, see if that has an effect, If I get the misfire again, i'll pull out the injectors, keep you posted, I hate not knowing the problem.
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Old 07-10-2008, 12:03 AM   #25
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Quote:
Originally Posted by afcivileng View Post
I went to full recerc on the bov, see if that has an effect, If I get the misfire again, i'll pull out the injectors, keep you posted, I hate not knowing the problem.

You're not alone man. My car is in the shop right now for the same problem.
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