Trying to resolve misfire codes p0302 p0304 p0301
Page 1 of 2 12 LastLast
Results 1 to 15 of 16

This is a discussion on Trying to resolve misfire codes p0302 p0304 p0301 within the General Maintenance, Troubleshooting & Accidents. forums, part of the Tech & Modifying & General Repairs category; Working my way through Donkey's misfire problem list... http://www.clubwrx.net/forums/genera...ease-read.html Events: -flashing CEL with p0304 and p0302 in VT on Jan ...

  1. #1
    Registered User
    Join Date
    Jan 2013
    Posts
    13

    Trying to resolve misfire codes p0302 p0304 p0301 p0303

    Working my way through Donkey's misfire problem list...
    IF YOU HAVE A MISFIRE CODE ,PLEASE READ THIS!!!

    Events:
    -flashing CEL with p0304 and p0302 in VT on Jan 1, cold morning, uphill, loaded car. Panic!
    -drove around a little staying out of boost
    -reset ECU (CEL returned)
    -Changed fuel filter (no change)
    -dry gas and full tank of 93
    -drove to PA staying out of boost (CEL still flashing intermittently)
    -upon arrival had p0304, p0302, p0301
    -replaced timing belt and pulleys/tensioner, new thermostat, new plugs NGKIridium BKR6EIX gapped to .029.
    -Leakdown test showed all cylinders under 5%
    -no change
    -unplugged MAF, no change.
    -drove 5 miles, no change.

    Next steps:
    -clean MAF
    -check FPR hose
    -try alternate, stock ECU
    -run can of BG44k
    -clean grounds
    -remove SPT intake and try stock airbox
    -I have fuel line leak warranty repair scheduled for next week. Could it be related?

    Anyone have any insight?
    Last edited by yosty; 01-14-2013 at 08:12 AM.

  2. Remove Advertisements
    ClubWRX.net
    Advertisements
     

  3. #2
    Registered User Ruh Roh's Avatar
    Join Date
    Dec 2011
    Location
    Pottstown PA
    Posts
    3,229
    do you have a tune on the car or still stock map?

  4. #3
    Registered User
    Join Date
    Jan 2013
    Posts
    13
    Quote Originally Posted by Ruh Roh View Post
    do you have a tune on the car or still stock map?
    PO told me it's Cobb AP stage 2, but said he had lost the AP...

    When I first got it it would boost to 15 psi and hold it but it had a bad up-pipe leak. Since I replaced the up-pipe with a Perrin one it would boost to 15 then oscillate down to 10 and settle at 13. Also, never threw an EGT code when I swapped the up-pipe. So leads me to believe it's not stock.

    Will try a stock ECU tonight and also Meeting up with someone with a Tactrix cable so hopefully I can find out what's on my ECU.

    Engine Mods (that I know about):
    TBE, Perrin Up-pipe, SPT intake.

  5. #4
    Registered User
    Join Date
    Jan 2013
    Posts
    13
    Update:
    -MAF cleaned, no change
    -stock ECU swapped in, no change except car is slower
    -grounds cleaned (2 on top of intake, 1 by battery, 1 on pass sidewall), no change
    -Checked the car with a Tactrix cable, it's only pulling timing around clutch engagement... Does that mean anything?
    -Put in a can of BG44k and got some gas (93 oct). So far driven about 20 miles on it, haven't noticed anything different

    At idle the car knocks badly and seems to be running on 3 cylinders. I get a p0304 within 20 seconds of starting it after an ECU reset.

    Once moving it seems to run fine but blinks the CEL once in a while and after driving I'll have some combo of every misfire code. p0304 and p0302 always, P0303 usually, I've only seen p0301 twice. No other codes.

    Next up:
    -back to stock airbox
    -FPR hose (need to find more info about exactly where/what the prob with this is)
    -fuel line recall
    -test/replace #4 injector

    Other ideas?
    Last edited by yosty; 01-09-2013 at 06:35 AM.

  6. #5
    Moderator Donkey's Avatar
    Join Date
    Apr 2005
    Location
    Da boonies
    Posts
    6,004
    I Support ClubWRX
    Until you do everything on the list there really is nothing else to offer. That was kind of the point of making the list as it pretty much has almost every single possible cause listed. How long have you had the car? Does it actually drive like it has a misfire or does it drive normal? Does it have a lightned flywheel?
    Resident Adviser @ WTF Tuning, LLC
    2002 FORESTER S
    1998 FORESTER S




  7. #6
    Registered User
    Join Date
    Jan 2013
    Posts
    13
    Quote Originally Posted by Donkey View Post
    Until you do everything on the list there really is nothing else to offer. That was kind of the point of making the list as it pretty much has almost every single possible cause listed. How long have you had the car? Does it actually drive like it has a misfire or does it drive normal? Does it have a lightned flywheel?
    Had the car about 2 months. I fixed an uppipe leak and replaced the front 02 sensor when I got it and it ran great until New Years Day.

    Drives great once moving. Idles badly (knocking, shaking).

  8. #7
    Registered User Ruh Roh's Avatar
    Join Date
    Dec 2011
    Location
    Pottstown PA
    Posts
    3,229
    what mods are done to the car besides stag 2 AP tune and SPT intake?

  9. #8
    Registered User
    Join Date
    Jan 2013
    Posts
    13
    Quote Originally Posted by Ruh Roh View Post
    what mods are done to the car besides stag 2 AP tune and SPT intake?
    TBE, Perrin Uppipe, SPT intake. Those are the engine mods I know about.
    When I did the timing belt, I put in a stock thermostat, believe it had a low temp before that.

    135k miles. dealer replaced headgaskets @ 72k. Was at dealership every 3k-5k miles until 90k.
    Last edited by yosty; 01-14-2013 at 08:05 AM.

  10. #9
    Registered User
    Join Date
    Jan 2013
    Posts
    13
    Update:
    -Put in stock airbox, no change.
    -FPR hoses and other vacuum hoses seem fine (sprayed starter fluid around with engine running, no change in idle speed)

    Above 1200 rpm engine stops shaking and noise goes away. Below that speed I get an obvious shake in the engine that seems to me as if its running on 3 cylinders. Also a noise that is a deeper and much louder version of the normal Subaru ticking noise.

    My current hypothesis is that my number 4 injector is leaking and causing the idle mixture to be too rich. At higher load (and higher fuel delivery) the effect of the leak would be less significant and the mixture might still be combustible.

    Plan:
    -continue to run through tank of gas with BG44k in it. (ordered gm top end cleaner, will try it when it arrives)
    -fuel line recall will be done at dealer on Wednesday, if problem is still happening I'll have them test my injectors while they have the intake off for the recall. (can anyone confirm they do have to pull the intake to do the fuel leak recall?)

    If that doesn't work... No idea.

  11. #10
    Registered User
    Join Date
    Jan 2013
    Posts
    13
    Confirmed. Dealer will pull the intake manifold for the fuel line recall:
    Click image for larger version. 

Name:	juzq6c.jpg 
Views:	42 
Size:	112.4 KB 
ID:	111041

    Car goes in to dealer tomorrow, will request compression check and test #4 injector.

    If it fails compression I'll be very sad and I'll suspect valve clearance.

    If #4 injector fails, DW 650s are going in and then I need a tune.

    If neither I'm stuck.

  12. #11
    Registered User
    Join Date
    Jan 2013
    Posts
    13
    30psi cylinder 4!
    160psi all others.

    Nuts. I suspect tight valve clearance burned a valve...

    Gonna pull the engine next week, either swap in JDM or refresh my heads and throw it back in.

  13. #12
    Registered User
    Join Date
    Jan 2013
    Posts
    13
    Burned exhaust valve number 4 cylinder!

    Well at least I know for sure what it was now.

  14. #13
    zax
    zax is offline
    \_(ツ)_/ zax's Avatar
    Join Date
    Nov 2008
    Location
    Neverland Ranch, Maryland
    Posts
    12,699
    I Support ClubWRX I Support ClubWRX
    Did you do a leakdown test to conclude it's the exhaust valve?
    2015 CWP WRX STi ... But how did I get roped back into an EJ motor?!
    Zax's utterly unimaginably stock 2015 STi build thread
    Zax's Shaggin' Wagon Build Thread Now tuned for 99% pure Unicorn Jizz!

    Zach | Moderator -- Mid-Atlantic States, Tech & Modifying & General Repairs
    Rollin' with the Bugeye Mafia #302 | N.E.R.D. Subject Zero
    Facebook me here

    Your Mid-A local board: http://www.clubwrx.net/forums/mid-atlantic-states/

  15. #14
    Registered User
    Join Date
    Jan 2013
    Posts
    13
    Nothing showed in the original leakdown test. Only in the compression test. I concluded it was the exhaust valve when I pulled the heads and looked at the valve...
    Click image for larger version. 

Name:	IMAG0512.jpg 
Views:	36 
Size:	61.8 KB 
ID:	111345

  16. #15
    Registered User
    Join Date
    Jan 2013
    Posts
    1
    What the F cause that? Not a pretty valve there!!

Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •