JonC

Hey guys,
So when I picked up the S2K the other month I noticed that it was running slightly rich. I could tell because there was carbon buildup on the tailpipes after the drive home and I could smell the richness.
Ive since put on a new O2 and some new NGK 7772 plugs and it definately helped out.

Problem is the car still smells a bit foul from the tailpipe. Highway driving doesnt seem to bother me, but low speed traffic does - fumes blow into the car and makes me nauseated.
I want to say it smells like a very slight richness mixed with a bit of burnt oil. The burnt oil smell seems to happen when the car has been running for at least 5 minutes which makes me think it might be oil blowby coming through the PCV system.

I know the early S2K's run a bit rich, but any advice or suggestions would be much appreciated.

The car is stock, fresh oil and fluids and 94 octane. Its in good running shape. Havent seen any exhaust leaks - did the rag-in-tailpipe test tonight and the smell definitely is coming out the pipes, No leaks onto the exhaust pipes themselves. Car has 140KM or around 86K miles.

Ive ordered an oil air separator which ill run as a small catch can to see if i can reduce any oil coming in that way to the system. The only other thing I can think of trying is running a thicker oil on my next oil change to see if that has any effect.

HarryD

Fresh intake filter? Fresh PCV? Unbolt the intake by the throttle body and check to see if you have oil/residue in there? Clean up the TB while you're in there.

Try resetting the ECU and doing the proper idle relearn procedure?

Hopefully this will cause it to run a little less rich?

LeonV

Sounds like you've got a test pipe in place of the catalytic converter.

Slowcrash_101

That's exactly what I was thinking.

Chuck S

-- Chuck

JonC

Both the filter and PCV are new. Already reset the ECU and also did spray TB cleaner in before I installed the plugs and O2.

JonC

Im sure its not, but ill check again when im under the car to see if the OE shield was put around a test pipe or something like that.

Car Analogy

Or maybe a gutted cat or a defective cat (and they used an O2 sensor spacer to prevent cel).

JonC

I bought it off an older gentleman. I cant imagine he was messing around with the cat. Id lean more towards it maybe being bad. There's no O2 spacer. I will check though next time im under the car.

toztigger

try a valve adjustment as a last resort, or look for an exhaust leak