Welcome to the North American Subaru Impreza Owners Club Thursday March 28, 2024
Home Forums Images WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Go Back   NASIOC > NASIOC Technical > Factory 2.0L Turbo Powertrain (EJ Series Factory 2.0L Turbo)

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.







* As an Amazon Associate I earn from qualifying purchases. 
* Registered users of the site do not see these ads. 
Reply
 
Thread Tools Display Modes
Old 09-20-2012, 07:10 PM   #1
redrex2002
Scooby Specialist
 
Member#: 118915
Join Date: Jun 2006
Chapter/Region: Tri-State
Location: Rochester, NY
Vehicle:
2002 wrx
srp

Default misfire code help please

hey guys, where do i begin...
i own 2002 wrx that i bought in 2005 with 42k miles on the clock. it now has 202k miles and i just recently gave it a fresh coat of paint. while doing the paint job and waiting for my mechanic buddy to put in some power steering lines the car sat around for about a month, only being started briefly to move it around the parking lot and the shop. i got my car back last night and started driving it around town running errands. i was able to drive maybe 5 or 6 miles before my cel started flashing at me. so i scanned the code and it was a p0304. so i had the car towed back to the shop today and i swapped out the coilpacks and the spark plug.

when i go to start the car and see if all is well it starts perfectly and runs normal for the first 30 or 45 seconds, then the motor starts to shake and run rough. then the check engine light begins to flash again and i shut it off.

i am at a loss for what to do next and rather frustrated. over this last summer i have put 800 dollars of paint and clear, as well as a starter (x4), cps sensor (x2), battery, spark plugs (x4), and one coilpack for cyl. #3 all to try and pix a p0335 cel that as still to this day eluded capture. i have all but run out of money at this moment, right now me and my wife are sharing one car which is getting almost impossible now that school has started.

please help me save my car, if anyone has any ideas as far as what i should look into next i would really appreciate it.

and now banna's
* Registered users of the site do not see these ads.
redrex2002 is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 09-20-2012, 07:58 PM   #2
pghana66
Scooby Newbie
 
Member#: 302066
Join Date: Nov 2011
Chapter/Region: South East
Location: Shallotte, NC
Vehicle:
2002 WRX
Aspen White

Default

have u had the timing belt serviced?
pghana66 is offline   Reply With Quote
Old 09-20-2012, 08:40 PM   #3
redrex2002
Scooby Specialist
 
Member#: 118915
Join Date: Jun 2006
Chapter/Region: Tri-State
Location: Rochester, NY
Vehicle:
2002 wrx
srp

Default

yes at around 120k
redrex2002 is offline   Reply With Quote
Old 09-20-2012, 08:54 PM   #4
GGSimpreza
Scooby Newbie
 
Member#: 291739
Join Date: Aug 2011
Location: Harrisonburg, VA
Vehicle:
99 RS coupe swappd
Silver Milage

Default

There are a ton of threads, search P0304. This misfire code can be everything from needing plugs replaced, to your motor having ringland issues.

Start diagnosing with the easy stuff, plugs and wires, moving them to different cylinders and check lights.

Best thing to do is a compression/leakdown test if you have the equipment. It's pretty cheap to get done.

You can search a ton, but there are so many causes you need to get your car looked at professionally if you don't have experience working on cars.


Quote:
Originally Posted by pghana66 View Post
have u had the timing belt serviced?
How would this be the first thing you ask about for a misfire?


Also, P0304 is a cylinder 4 misfire, not 3.
GGSimpreza is offline   Reply With Quote
Old 09-20-2012, 10:45 PM   #5
pghana66
Scooby Newbie
 
Member#: 302066
Join Date: Nov 2011
Chapter/Region: South East
Location: Shallotte, NC
Vehicle:
2002 WRX
Aspen White

Default

Quote:
Originally Posted by GGSimpreza

How would this be the first thing you ask about for a misfire?
was looking at the other code in the thread saw cps was maintenaced, car starts but then goes awkward. 200k, figured id ask as didnt see it in the listed updates.
pghana66 is offline   Reply With Quote
Old 09-20-2012, 11:23 PM   #6
redrex2002
Scooby Specialist
 
Member#: 118915
Join Date: Jun 2006
Chapter/Region: Tri-State
Location: Rochester, NY
Vehicle:
2002 wrx
srp

Default

my mechanic said i should try and find out where the pcm is located, he said i might have a bad ground somewhere in there because we have eliminated the plugs coilpacks and wires unless there is a broken wire somewhere in the harness.

on a side note does anyone know if the engine wiring harness from a 2004 wrx will swap into my 2002 wrx?
redrex2002 is offline   Reply With Quote
Old 09-20-2012, 11:55 PM   #7
nomoredsm
Scooby Newbie
 
Member#: 281987
Join Date: May 2011
Location: Philadelphia pa
Vehicle:
2007 wrx
blue

Default

i strongly suggest a compression check and if good then a leakdown test.. My 02 wrx acted similarly when piston #4 had a cracked ringland. I changed plugs, swapped coilpacks, cleaned grounds, cleaned maf, but rather than waste $ i just swapped the coilpacks to see if the miss went from cyl 4 to another and when it didnt i did a hot compression check to find only 90psi in cyl 4. Also, if cyl 4 is missing then you will most likely wipe out rod bearings in cyl 2, i did.. Its a horrible feeling to find that a rebuild is whats needed, so have some ginger ale handy to calm that sick stomach!!
nomoredsm is offline   Reply With Quote
Old 09-21-2012, 12:14 AM   #8
TwoFifty
Scooby Newbie
 
Member#: 261764
Join Date: Oct 2010
Location: Kelowna BC
Vehicle:
2003 Impreza WRX
Blue

Default

The best place you can start with a misfire in my opinion is this,

Swap plug from cyl 4 to different cylinder, see if misfire follows

Swap coil from cyl 4 to different cylinder, see if misfire follows

Swap injector from cyl 4 to different cylinder, see if misfire follows.

If code follows part then you know where the problem lies.

If not could be an internal engine issue, Perform Compression test and leakdown test!

In fact you can perform a compression test while you've got that plug out to move it, might save you a little time depending on the results.
TwoFifty is offline   Reply With Quote
Old 09-21-2012, 04:56 PM   #9
redrex2002
Scooby Specialist
 
Member#: 118915
Join Date: Jun 2006
Chapter/Region: Tri-State
Location: Rochester, NY
Vehicle:
2002 wrx
srp

Default

thanks guys i am not shure that it is an internal problem. because when i start it up it takes 30 seconds to a minuet for the light to start flashing. then if i clear the code while it is running it runs fine for annother min. then the light starts blinking again. i would think that if a valve is sticking or a ringland was cracked then it would start flashing as soon as i started the car and would return immediatly after being cleared while it was running
redrex2002 is offline   Reply With Quote
Old 09-22-2012, 01:13 AM   #10
laxton
Scooby Newbie
 
Member#: 324094
Join Date: Jun 2012
Chapter/Region: Tri-State
Vehicle:
02 wrx
wrb

Default

I HAD THE EXACT SAME PROBLEM! Changed coil packs and plugs and cleaned mafs.. Still nothing. Done a comp test and it was 80psi! Put in a scope and seen bad valves so I got all new ones. When the head was removed I descovered I has multiple cracks in my head. (explanes why it runs fine when cold) its bc the cracks were small but as it heated up the cracks would expand and I would lose more compression. Please take my advice and get a test ran to save u more time.
laxton is offline   Reply With Quote
Old 09-22-2012, 10:30 AM   #11
redrex2002
Scooby Specialist
 
Member#: 118915
Join Date: Jun 2006
Chapter/Region: Tri-State
Location: Rochester, NY
Vehicle:
2002 wrx
srp

Default

thanks i definitely will. i have access to a totaled 2004 wrx is there anything stopping me from swapping that motor and harness into my car?
redrex2002 is offline   Reply With Quote
Old 09-22-2012, 12:43 PM   #12
Haelan
Scooby Specialist
 
Member#: 151045
Join Date: Jun 2007
Location: Pennsylvania
Default

Quote:
Originally Posted by redrex2002 View Post
thanks i definitely will. i have access to a totaled 2004 wrx is there anything stopping me from swapping that motor and harness into my car?
Why not do a compression test on cylinder #4 first? You'll know in 10 minutes whether there is a major problem or not.
Haelan is offline   Reply With Quote
Old 09-23-2012, 01:03 PM   #13
nomoredsm
Scooby Newbie
 
Member#: 281987
Join Date: May 2011
Location: Philadelphia pa
Vehicle:
2007 wrx
blue

Default

Quote:
Originally Posted by Haelan View Post
Why not do a compression test on cylinder #4 first? You'll know in 10 minutes whether there is a major problem or not.
You can lead a horse to water, but cannot make him drink
nomoredsm is offline   Reply With Quote
Old 09-23-2012, 01:23 PM   #14
redrex2002
Scooby Specialist
 
Member#: 118915
Join Date: Jun 2006
Chapter/Region: Tri-State
Location: Rochester, NY
Vehicle:
2002 wrx
srp

Default

i am going to have my mechanic do a compression test but my car is at work right now and i do not have access to it untill monday. i am obviously going to perform all the tests and check before i get involved in a motor swap i was just making sure that if it does come down to a bad head or piston etc. that i can use a motor from a 2004 wrx with half the miles that my car has and was running up untill a week or so ago when my friend rear ended a dump trunk lol bad for him great for me potentially
redrex2002 is offline   Reply With Quote
Old 09-24-2012, 10:31 AM   #15
frostmasta
Scooby Newbie
 
Member#: 217178
Join Date: Jul 2009
Chapter/Region: South East
Location: Maryville, TN
Vehicle:
2003 WRX
WRB

Default

I had same issue, turns out the timing belt had slipped 1 tooth off.
frostmasta is offline   Reply With Quote
Old 09-24-2012, 01:41 PM   #16
redrex2002
Scooby Specialist
 
Member#: 118915
Join Date: Jun 2006
Chapter/Region: Tri-State
Location: Rochester, NY
Vehicle:
2002 wrx
srp

Default

if the timing belt was mis-aligned wouldent both cyl. number 2 and 4 be having problems? annother thing to dbl. check i guess thanks guys. i am trying everything i can to save my baby. just got to wait for my mechanic to have time to get it in and start running down the list of possible problems
redrex2002 is offline   Reply With Quote
Old 10-01-2012, 03:18 PM   #17
redrex2002
Scooby Specialist
 
Member#: 118915
Join Date: Jun 2006
Chapter/Region: Tri-State
Location: Rochester, NY
Vehicle:
2002 wrx
srp

Default

ok i finally had time to do the compression test today. the results were

cyl. 1, 135 psi
cyl. 2, 142 psi
cyl. 3, 132 psi
cyl. 4, 148 psi

it seams that the motor and its internals are A-OK, especially for the amount of miles that i have on her. lol i guess running 4 quarts of mobil 1 full syn. and a quart of lucas really does do the trick lol.

any more ideas of where to look next. wensday probable i am going to JB weld a peice of scrap metal over the flex section of my downpipe because i have a really big exhaust leak commin from there. hopefully that helps but i am still open to any other things to check out.

and thanks for all the help so far guys.
redrex2002 is offline   Reply With Quote
Old 10-01-2012, 06:46 PM   #18
quazimoto
Scooby Guru
 
Member#: 70395
Join Date: Sep 2004
Chapter/Region: MAIC
Location: Da-boonies,Va
Default

quazimoto is offline   Reply With Quote
Old 10-01-2012, 08:05 PM   #19
Kastley85891
Scooby Specialist
 
Member#: 127704
Join Date: Oct 2006
Chapter/Region: TXIC
Location: TX/Austin
Vehicle:
2015 Boosted Stang
MAP tuned

Default

My fix was as simple as a loose negative battery terminal
Kastley85891 is offline   Reply With Quote
Old 10-15-2012, 01:29 PM   #20
redrex2002
Scooby Specialist
 
Member#: 118915
Join Date: Jun 2006
Chapter/Region: Tri-State
Location: Rochester, NY
Vehicle:
2002 wrx
srp

Default

hey guys finally got my misfire problem figured out last friday. finally got around to swapping the fuel injectors around and sure enough the misfire went from #4 to #2, so out came all 4 injectors and i shipped em all out to deatschwerks saturday. hopefully ill get em back thursday and i can have my baby up and running by the weekend. damn it feels good to finallyhave this problem figured out it only took me a month and a half to find the time lol
redrex2002 is offline   Reply With Quote
Old 10-15-2012, 03:50 PM   #21
CanadianImprezaSTi
Scooby Newbie
 
Member#: 312159
Join Date: Mar 2012
Chapter/Region: W. Canada
Location: Lethbridge, AB.
Vehicle:
2004 WRX
Blue

Default

Glad to hear you solved it without a rebuild!

Quote:
Originally Posted by laxton View Post
I HAD THE EXACT SAME PROBLEM! Changed coil packs and plugs and cleaned mafs.. Still nothing. Done a comp test and it was 80psi! Put in a scope and seen bad valves so I got all new ones. When the head was removed I descovered I has multiple cracks in my head. (explanes why it runs fine when cold) its bc the cracks were small but as it heated up the cracks would expand and I would lose more compression. Please take my advice and get a test ran to save u more time.
Sorry to drift off topic, but since metal expands under heat wouldn't it close the cracks as it got hotter?

Not to mention, small cracks in the heads of a WRX are fairly common.

I'd say your valves were the only issue.

Joel
CanadianImprezaSTi is offline   Reply With Quote
Old 10-15-2012, 07:57 PM   #22
danger1138
Scooby Specialist
 
Member#: 279525
Join Date: Apr 2011
Chapter/Region: Tri-State
Location: QUEENS NY
Vehicle:
06 Fxt

Default

Damm. I love good endings!! Gives me hope in regards to po304 code on my hybrid setup. Though i doubt its a piston problem in mines but u never know.
danger1138 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

All times are GMT -4. The time now is 01:06 PM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2024 Axivo Inc.
Copyright ©1999 - 2019, North American Subaru Impreza Owners Club, Inc.

As an Amazon Associate I earn from qualifying purchases.

When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission
Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.