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Discussion Starter #1
Hi all,

98 Outback, Manual trans, 180k kms is misbehaving.

Started unusually rough, idled poorly but got better after revving up to 3k RPM. I had no CEL so I tried pulling out but it had zero power below 3000 RPM.

...after about 3 minutes of driving I pulled it back to my garage...still no CEL. when i got out of the car I smelled smoke!

Looking underneath the entire exhaust up to the last catalytic converter was glowing red hot! :gasp: Oddly panicking didn't help so I've moved on to a diagnosis...

Plugged cat?
Bad spark plugs/wires?
Burned valve?
Witchcraft?
Bad ECM?
Stuck injector?
Gnomes with blowtorches?

...the main cause of this would be unburned fuel dumping into the exhaust right?

...any ideas?
 

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I simply cannot abide useless people.
2006 2.5i and 2002 3.0 wagons.
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Probably a plugged cat. Which may have been caused by another issue. any chance your CEL is burned out? It really should be on in the situation you describe. Might see if there are any stored codes.

Also: when was last tune up? Age of plugs, wires, etc?
 

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Discussion Starter #3
OK - the CEL must have thrown the code just as I turned it off. I checked it tonight and it's there:

P0303 Code - Cylinder #3 Misfire
P0304 Code - Cylinder #4 Misfire

...and to make things worse...now it's running fine. No overheating cat.

Bad coil? i can't image 2 plugs & wires failing at the same time on only one bank?
 

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I do not think cat have any thing to do with it.
Timing. This is only one explanation.
For unknown reasons timing get shifted "up" and most of the gas instead in cylinder burned in exhaust.
I do not think timing belt was guilty......
 

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2001 Outback 5 speed, 2000 Outback Automatic, 2002 Legacy Wagon Automatic. All 2.5L
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Gotta agree with fuel being dumped into the exhaust. I've experienced this before, tho not on a subie. In my case is was a flaky ignitor that would crap out after warm up.
 

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2006 2.5SE manual
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Unfortunately the way the Lambda sensor information is used by the ECU makes any misfire problem worse (hence the 'turn off immediately if you get a misfire' warnings in the owners manuals). A misfire on one cylinder gives oxygen in the exhaust that the Lambda sensor detects and the ECU assumes is due to running lean. So the ECU richens up the mixture so you have plenty of spare fuel entering the exhaust and an engine that is running so rich it can't pull the skin of a rice pudding and the cat is heating up like crazy.

Hopefully the cats will have survived.
 

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Gotta agree with fuel being dumped into the exhaust. I've experienced this before, tho not on a subie. In my case is was a flaky ignitor that would crap out after warm up.
In the old cars with distributor cup, and timing adjusted by rotating distributor assembly it was very common problem.
With short exhaust "pipes" you can produce spectacular flames.
;)
 

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Discussion Starter #8
Hmmm...interesting ideas, thanks guys. That is indeed a BAD ecu design. I've played with the Motronic 2.7 and didn't think there were any dumber...now I know...

The car had sat unused for 4 days, i wonder if that was a factor? I will give it a good thrashing on the weekend and see if anything new comes up.

The cats only glowed for about 2 mins - not long enough to melt the catalyst. The area I live in does not regulate cats...I may try a test here with them off.


...any ideas as to why it is just the passenger side cylinders?
 

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Hmmm...interesting ideas, thanks guys. That is indeed a BAD ecu design. I've played with the Motronic 2.7 and didn't think there were any dumber...now I know...

The car had sat unused for 4 days, i wonder if that was a factor? I will give it a good thrashing on the weekend and see if anything new comes up.

The cats only glowed for about 2 mins - not long enough to melt the catalyst. The area I live in does not regulate cats...I may try a test here with them off.


...any ideas as to why it is just the passenger side cylinders?
I have the exact same issue, please let me know if you find anything.
 

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I had a similar issue a couple years ago. Mine was cylinder 3 intermittent misfire. After a few days it was a constant misfire. Ended up being bad coil pack. Because of unburnt fuel entering the catalytic converter it ended up failing a year after it was installed so I had to replace the coil pack and catalytic converter.
 
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