Black carbon like material on driveway?

[TigerDale]

Bought my 1st Corvette (black 1990 w/110k) and love it, but it has a few problems. My mechanic told me it is running too rich and when I start it in the mornings it leaves a black carbon like residue on the carport concrete under the exhaust. I don't know much about mechanics so I need some help. Is this a problem I need to be concerned about? It runs great on the highway, but has a little back and forth surge at idle. Any advice would be appreciated. Thanks.

 

[Tuna]

That is probably the ash residue build up in the exhaust being 'washed out' by the water vapor created by the burning of the gas. It may be running a little richer than it should be.

Try a fuel system cleaner like RedLine (check Mid America's catalog) and clean the throttle body with a TB cleaner spray.

 

[Robertwav1]

Hmmm....wonder when the O2 sensors were changed? I would say the mileage warrants newbies.

 

[TigerDale]

That is probably the ash residue build up in the exhaust being 'washed out' by the water vapor created by the burning of the gas. It may be running a little richer than it should be.

Try a fuel system cleaner like RedLine (check Mid America's catalog) and clean the throttle body with a TB cleaner spray.

Thanks Tuna, I will give it a try.

 

[TigerDale]

Hmmm....wonder when the O2 sensors were changed? I would say the mileage warrants newbies.

Do you think this could also cause the engine to surge at idle? Might solve 2 problems with 1 fix. Also, do you know if this is very expensive? Thanks.

 

[Vettelt193]

Bad O2 sensors will cause all sorts of problems... including the surging idle. Not too expensive, you can do it yourself if you are a bit handy. You need a special socket to get them out though.... the socket and sensors should be available at any regular parts place. I usually get the cheap ones and splice the wires myself, because the ones with the 'oem connector' are usually rediculously priced.

 

[vetteboy86]

Those are all good suggestions. How long has it been since the car had a tune up. All these things help, and if you are going to keep the car a while, they are also a good idea. If the car is not throwing any codes, then i wouldn't think there are major problems


good luck

craig

 

[TigerDale]

How long has it been since the car had a tune up. All these things help, and if you are going to keep the car a while, they are also a good idea. If the car is not throwing any codes, then i wouldn't think there are major problems


good luck

craig

No codes & I had it tuned up and a fresh Mobil One oil change the day after I bought it. I think I can relax a little now and check out these suggestions. I will let y'all know how it turns out, Thanks for all your help guys.