Catalytic converter overheating?

**MainFrame** · 01-04-2013 01:00 PM

Originally Posted by dttruax

Question: would this code mean that the pre-cat is going bad, or just the mid-cat?

Either, both, neither.. there are a lot of things that could cause that reading. Failed sensor, exhaust leak, rich or lean condition, or a problem with one of the three catalytic converters. I would not suspect that code to be thrown by a failing uppipe cat though, since you can run catless uppipe without having to worry about throwing that code.

**dttruax** · 01-04-2013 01:14 PM

The other symptoms (like the hot almost burning smell coming from under car/engine bay makes me believe the cat was overheating, etc.

Now, there's no cat in the downpipe, correct (item "M" on the schematic on the previous page)?

**MainFrame** · 01-04-2013 01:24 PM

Originally Posted by dttruax

The other symptoms (like the hot almost burning smell coming from under car/engine bay makes me believe the cat was overheating, etc.

Now, there's no cat in the downpipe, correct (item "M" on the schematic on the previous page)?

The stock downpipe should have a catalytic converter in it..

A lean condition can cause excessive heat. But if the car is stock I wouldn't expect it to run lean unless there's a mechanical problem somewhere.

**Mikie13** · 01-04-2013 01:26 PM

Stock downpipes have 2 in them.

**dttruax** · 01-04-2013 01:33 PM

Originally Posted by Mikie13

Stock downpipes have 2 in them.

So...... there's actually 4 converters on a 2004 WRX?

**MainFrame** · 01-04-2013 01:34 PM

Originally Posted by dttruax

So...... there's actually 4 converters on a 2004 WRX?

Three

**dttruax** · 01-04-2013 01:37 PM

I only ask because my mechanic is having a heck of a time w/the local Subaru dealer and getting the correct part. My mechanic basically thinks the converter in the downpipe (item "M" on the subarupartsforyou schematic.... which I can't find anywhere) is bad and needs to be replaced, but Subaru sent him the mid-cat assembly (item "P").... and I think the dealer wanted over $800 for the downpipe assembly.

**SKI.WRX** · 01-04-2013 01:45 PM

Buy used off someone who went stage 2. You can probably get the whole stock exhaust for $1-200.

Also check the wires from the rear O2 sensor. Mine rubbed on the drive shaft and it has worn away the housing shorting the sensor on the drive shaft. I had a P0420 code and no CEL. Just passed Colorado Emissions with it that way as well.

**MainFrame** · 01-04-2013 01:49 PM

Originally Posted by SKI.WRX

Buy used off someone who went stage 2. You can probably get the whole stock exhaust for $1-200.

^this

**dttruax** · 01-04-2013 01:53 PM

Originally Posted by SKI.WRX

Buy used off someone who went stage 2. You can probably get the whole stock exhaust for $1-200.

Also check the wires from the rear O2 sensor. Mine rubbed on the drive shaft and it has worn away the housing shorting the sensor on the drive shaft. I had a P0420 code and no CEL. Just passed Colorado Emissions with it that way as well.

Know anyone???

**dttruax** · 01-04-2013 02:09 PM

anyone know the part # for the downpipe assembly w/converter for a 2004 WRX?

**MainFrame** · 01-04-2013 02:13 PM

Originally Posted by dttruax

Know anyone???

FS: (For Sale) 2005 WRX Stock Downpipe and Up pipe - NASIOC

there are several others listed too..

**dttruax** · 01-04-2013 02:35 PM

Originally Posted by MainFrame

Three

So since there's 2 converters between the 2 oxygen sensors, it could possibly be one, either, or both that might be bad. Oh goody.

**UEDan** · 01-04-2013 02:44 PM

Since we already suggest you replace the stock up with a catless unit....

GET A (used) CATLESS DOWNPIPE!
Your car is a 2004. $10 Vagcom cable + $50 XPT tune. More power, better fuel economy and no more friggen cats!