Welcome to the North American Subaru Impreza Owners Club Sunday December 21, 2014
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC Technical > Normally Aspirated Powertrain

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.
* Registered users of the site do not see these ads.
Reply
 
Thread Tools Display Modes
Old 07-28-2013, 07:56 PM   #1
MikeC5
Scooby Newbie
 
Member#: 104702
Join Date: Jan 2006
Location: South Eastern CT
Vehicle:
95 Legacy
Green

Default Misfire Codes

My '02 2.5L is throwing occasional misfire codes. I did go through the FAQ and read through several threads on this issue but many of them don't have a resolution of the problem posted.

About 2 months ago I replaced head gaskets (Six Star) and replaced all gaskets/seals, plug wires and plugs while engine was out. A few days after it was back on the road I got a cel for P0301. I cleared it and it has been O.K. for the last 2 months. Engine light comes on the other day and I'm getting P0301, 2, 3 and 4 plus pending on 1 and 2. The car seems to run fine, idles fine, gas mileage is around 25 mpg which is what it usually is... WTF?

I never saw any misfires before doing HG (in 70K miles that I've owned it). I did adjust valves while heads were off and cleaned up the piston tops and combustion chambers....

I plan to pull the plugs next and see if they look funny.
* Registered users of the site do not see these ads.
MikeC5 is offline   Reply With Quote
Old 07-30-2013, 01:26 PM   #2
MikeC5
Scooby Newbie
 
Member#: 104702
Join Date: Jan 2006
Location: South Eastern CT
Vehicle:
95 Legacy
Green

Default

Pulled the plugs and they looked fine. They are new AC plugs, not NGK and are just plain old single electrode plugs (which had never previously been a problem). The gap was right at 1 mm. I will admit to using Autozone for replacement plug wires (Bosch, I think). I replaced the fuel filter while under there and cleaned up engine/firewall grounds, no obvious vacuum leaks. I tried misting water on the coil pack while running at night and saw no arcing. Driving it to work this morning (40 miles) it ran fine but I did see engine light come on for maybe a second and then off. I read that a blinking light could mean damaging misfires but wouldn't the light eventually stay on?
MikeC5 is offline   Reply With Quote
Old 07-30-2013, 08:32 PM   #3
MikeC5
Scooby Newbie
 
Member#: 104702
Join Date: Jan 2006
Location: South Eastern CT
Vehicle:
95 Legacy
Green

Default

Light stayed on this afternoon.. Misfire on all 4 plus a pending 0420. You guys are really a great help...
MikeC5 is offline   Reply With Quote
Old 07-31-2013, 02:37 AM   #4
rhino6303
Scooby Newbie
 
Member#: 181314
Join Date: May 2008
Chapter/Region: NWIC
Location: SW Washington
Vehicle:
2005 Impreza OBS SRR
05 Legacy GT RBP

Default

You are having misfires on all cylinders? I am thinking any of the following to check or check again:

Spark plugs (get some ngk)
Coil
Injectors
Check resistance on plug wires

Are your battery terminals clean and tight?
rhino6303 is offline   Reply With Quote
Old 07-31-2013, 06:49 AM   #5
MikeC5
Scooby Newbie
 
Member#: 104702
Join Date: Jan 2006
Location: South Eastern CT
Vehicle:
95 Legacy
Green

Default

What should resistance on plug wires be? For the coil, I can swap it out for another one. I don't think there would be much point doing reistance checks since the problem is intermittent (and car starts & runs fine). Battery connections are good. Since this only started happening after an HG and clutch job (engine removed) with new plugs & wires, I'm hoping it is one of the latter two...
MikeC5 is offline   Reply With Quote
Old 07-31-2013, 06:37 PM   #6
MikeC5
Scooby Newbie
 
Member#: 104702
Join Date: Jan 2006
Location: South Eastern CT
Vehicle:
95 Legacy
Green

Default

The Bosch plug wires measure around 800 ohms and the manual says they should be between (roughly) 5k to 12K ohms. I checked one on our other Outback and it measured around 2.5k (non-OEM). I did go ahead and swap the coil with one that I knew worked when removed. We'll see. I may have to bite the bullet and get some NGKs and OEM wires...
MikeC5 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 12:51 PM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2014 Axivo Inc.
Copyright ©1999 - 2014, North American Subaru Impreza Owners Club, Inc.