Injectors, timing, low cylinder pressure.
black,grey
its not always a bad thing its just your oil usually when the engine is still cold
Black smoke means you're burning fuel, blue smoke, you're burning oil, white smoke, you're burning coolant.
You're burning oil. either your piston seals are not working or you have other seals that have gone bad resulting in oil entering the combustion chamber.
grey exhaust smoke is caused by your engine burning oil during the combustion process. this could be caused by a piston ring that doesnt properly seal, or another leak in your engine.
The carburetor needs calibration or changing of possibly defective part, for example, gasket or needles.
Why is smoke coming out of my 96 s10 oil fill and exaust blowing grey smoke
if there is backfire, check the exhaust restriction....
Sounds like you need a ring job, white/grey smoke from the exhaust usually means oil is burning in your engine. Your engine may need a tune up or a compression check, bring it in to your mechanic.
Grey/whitish smoke usually burning water/black smoke usually burning oil-could be head gasket issue. Look for signs of water loss, overheating or water in oil pan.
Literally hundreds of things could cause unusual exhaust color/smoke. To help, here's the general idea of colors and causes: Blue/grey- Burning Oil White-Burning Coolant (and in some cases transmission fluid) Black- Burning Excessive Fuel Hope that helped