Whenever I start my car this black, wet, powdery soot flies out of the tailpipe and onto my garage floor. Only seems to do it AT ignition and does not continue to do it.

The only thing I recently changed was the pre-catalyst O2 sensor to cancel a check-engine light (which didn't work, but that's another story).

Any ideas as to what is causing this?

Thx

2/17/2007 12:55:55 AM

maybe you have a fireplace in your car somewhere....
call a chimney sweeper

2/17/2007 1:02:50 AM

on startup your o2 sensors arent doing anything anyhow, and condensation/soot are normal by products of an internal combustion engine. so its likely normal, depending on how much there is. otherwise you are running rich, or simply not completely burning the fuel you are getting, which could be for several reasons. post what year/make/model your car is and im sure 69 will tell you which TSB it is.

2/17/2007 11:23:36 AM

'96 Volvo 850 GLT (there's the first problem)

OBD2 read "Bank 1 fuel trim rich (idle)" which makes sense...so now what do i do?

2/17/2007 4:40:35 PM

check your plugs and ignition system first, fouled plug will cause that commonly without a misfire code, and check for air restrictions, such as a dirty as air filter

-69

2/17/2007 5:59:40 PM

awesome, thanks for the tips

the air cleaner is pristine...ill check the plugs

you think if i clean/gap the plugs and check the distributor, that might clear the code also?

the only thing i thought that might be still causing that is a short / fault between the ECM and the sensor.

2/18/2007 5:35:56 PM