Jump to content
Ultimate Subaru Message Board

98 OBS running rough 2.2 5sp


Recommended Posts

Glad to see the USMB is Back!

 

98 2.2 Impreza 5 sp 262K with about 160K on the engine.

 

It's been running rough for a while, noticeable at idle, with more shaking the a smooth Subaru engine should have. Until the last few days, there have been no codes over the last 8 months I've noticed this.

 

The codes posted P0301 and P0303, miss fire on 1&3.

 

I've checked and done the following to get it running right.

- New NGK Plugs,

- Air Filter

- Swapped Plug wires

- Fuel System Cleaner

- Checked for vacuum leaks

 

None of these fixed the problem, although slight improvements were noticed. This has been a very slight problem until the last day or so.

 

With the codes showing, I pulled the plug wires one at a time, all produced a drop in RPM.

 

I pulled the injector plugs one at a time, #3 produced little or no change in idle. Ohm the injectors, all were 11.7 Ohms.

 

I had another coil, so I swapped them, no change.

 

I had a set of 2.5 injectors, so I swapped them, slight change still rough.

 

I can hear a Pop Pop in the exhaust.

 

I'm going to do a compression test and check the timing marks tonight.

 

What else am I missing?

 

Thanks, Larry

Link to comment
Share on other sites

i chased something similar a little while ago on my 96 Leg. EJ22 and i turned out the connectors for the fuel injectors were swapped so obviously it was injecting fuel at the wrong time....worth a quick check....as for the plugs and wires im assuming you you used OEM?....to check for the vacuum leaks did you do a vacuum test?...if not i would do a vaccum test and see what you get.....

Link to comment
Share on other sites

I'm not sure you're missing anything - be interesting to see if one side has slipped valve timing. You could try holding a small stip of paper to the tail pipe. If it tries to 'suck in' that could mean a valve is open when it shouldn't be. I dunno if that trick works if timing is off by just 1 or 2 teeth though.

 

Maybe there is a fuel pressure/delivery problem?

Link to comment
Share on other sites

When you say you "swapped plug wires".... what exactly did you do?

 

The EJ engines like new plug wires about annually. OEM or NGK are recommended.

 

1/3 use the same side of the coil (wasted spark ignition) so that vaguely points to an ignition failure - I would normally suspect the coil but you swapped that out.

 

GD

Link to comment
Share on other sites

I pretty much have it down to #3 not firing due to lean fuel. I thought I had it a few times when I did the following, but the problems comes back on #3 cylinder.

 

Cleaned all the Engine Connectors

Cleaned the MAF and then swapped in one I had (seem to help the most)

New Subaru Plug wires, no change

 

Pinch the fuel return line and the RPM increases some so I'm going to tee in a pressure gauge and change the filter. My Manual says 2.6 to 3.3 PSI for fuel Pressure is that correct?

 

Full system voltage at the Injector 14.2 Volts engine running. When I have the rough running at Idle pull the #3 injector plug has no effect on the RPM.

 

The plug is white as can be, lean. More after I test the fuel pressure.

Thanks for the ideas, Larry

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...