some black smoke only above 5-6k

[performancered]

My 93 atx sho with about 77,000 on it just had the tranny rebuilt. I wanted to try it out and the first few time I hit it there was black smoke out the rear starting around 5 or 6k. then when i floored it the same later that drive it did it less and less 3 or 4 times then i couldn't see any from the drivers seat next time I hit it. Is this most likely carbon from slow city driving, or plugs and wires being original. I also am showing a code o2 sensor causing left bank i believe to be running lean.

 

[projectSHO89]

Black smoke under heavy load is not abnormal.

If you don't like the black smoke, don't jump on the gas pedal too hard. Might as well drive a SLO in that case...

steve

 

[performancered]

projectSHO89:
Black smoke under heavy load is not abnormal.

If you don't like the black smoke, don't jump on the gas pedal too hard. Might as well drive a SLO in that case...

steve

Ok but do you know what causes the smoke on the sho's, does it always happen? My 93 has about 77,000 and has original wires, possibly plugs and the timing belt. It also a code currently on the 02 causing one of the banks to run lean. No It would be kind of pointless to drive slow with such a nice car.

 

[rangerj]

Performancered,

If you have a faulty O2 sensor, then the computer compensates by running the engine rich. This protects the engine from the damage that running lean can do.

If you are running rich, then you will see black smoke. If the O2 sensors are the same age, or milage, then replace them both if your budget allows for it. If not, replace the offending sensor and plan on replacing the other one soon.

Hope this helps, rangerj

 

[mygreensho]

i have the same problem on my 93 only its a lil different...when i hit the gas hard to pass a car or get on the interstate around 5-6k rpm's i get a nice smokey white plume of exhaust....im thinking this is either a sticking valve or a bad valve spring? am i correct?...i know its not good

 

[rangerj]

Mygreensho,

If you're getting thick white smoke, commonly associated with burning oil, a common cause is bad valve seals. Do you get a "puff" of white smoke on start-up, or starting out (as from a light or stop sign)?

Burning oil has a distinctive odor which can also help to diagnose the problem. Stand behind the car while a helper starts the car. Watch for the thick white (grey or bluish white) smoke, and the distinctive smell of burnt oil.

If the smoke is thin, white, (wispy) and smells like anti-freeze, thats a different problem, e.g. head gasket.

Hope this helps, rangerj