Black Soot coming from exhaust

[91SHOPLUS]

Hi,
Since I got my car 7 months ago it has been spraying black dust from the mufflers. It is not smoke. It is clear as water but the back bumper is covered by the end of the week. I am not sure if it is related but about 2 months ago I replaced my mufflers with glasspacks and the since then the exhaust has smelled like coolant or gas. Do these things mean I have bad cats or 02 sensors.

THANKS,
Brian

<small>[ August 02, 2002, 11:16 PM: Message edited by: 91SHOPLUS ]</small>

 

[SHOfun 93]

Some carbon buildup is relatively normal for these cars, but if your o2s are going bad, it might send a lean signal to the computer causing the engine to run rich to compensate. I would change the o2s if it is time for them to go.

 

[SHODWN]

if its running that rich, I would think the PCM should flip the CE light. No?

Im having a similar issue, but my car only runns a 100' at a time.

 

[sdpatt]

That billboard is great. Tired, old O2 sensors don't have to create a CE light to cause the engine to run outside of its normal envelope of air:fuel. Since the O2 sensors are the only input the EEC has regarding the accuracy of the mixture, if they are inaccurate, the EEC only knows what the sensors are telling it.

The sensors get old and tired and slow down in their switching from lean to rich. This allows the engine to run both over-lean and over-rich. Neither is beneficial to performance or emissions.

It is recommended that the O2 sensors be replaced at the same intervals as the spark plugs - 60,000 miles in the case of our SHOs. If you O2 sensors are over 60,000 miles old, you would be well served in replacing them. I recommend the Bosch sensors available from AutoZone.

3.0L: Bosch 13942 $38.99
3.2L: Bosch 13223 or 15716 $40.99

 

[srfdude]

Just an update on AZ prices for the Bosch O2s. In California they go for ~$45; I just bought a pair and looked all over for a cheaper price. No luck.
Mike