What makes a car smoke out the exhaust when you push on the gas?

Question

The car is a 1991 Nissan Maxima, 5 speed, 6 cylinder, runs great but smokes a lot. Is the car worth keeping if it does this? Is it reliable?

Answer 1

White smoke usually means a worn out engine, black smoke means a problem with the engine getting more fuel than it can burn properly. Could be a simpler problem with a faulty sensor on the engine. Worst case scenario is worn out piston rings or worn out valve guides in the head. Some cars run for a long time like this. Only a good mechanic can take a look and find the problem. If it only puts out black smoke under acceleration, there is a fuel system malfunction. A worn out engine will usually smoke all the time.

Answer 2

Depends on the color of smoke. Blue is oil, black is fuel, and white is water. If it's blue or white you will want to do a compression check and find out which head gasket is blown. Also check the spark plugs, etc. If all of the cylinders are burning oil then you will have bad rings. If it's black smoke, you will need to check the fuel system. MAP sensor, O2 sensor, or TPS. Good luck.

Answer 3

Well you are burning stuff in each cylinder. Where there's fire, there's smoke!

You could have a water leakinto one ore more cylinders. Are you losing coolant?

You could be burning oil. Does the oil level vary? That could be worn rings, valve guides or seals, or a bad pcv valve.

You could also be using more fuel than the engine can burn. Hows the gas mileage lately? This could be a bad fuel pressure regulator, or bad ignition parts (plugs, wires, etc.)

Answer 4

Sounds like you need a valve job.Valve seals go bad and let oil seep past the valve and into the combustion chamber. Corrosion on valves also doesn't let them seat properly when closed. Check around for prices as the valve job could be more than 2x what the car is worth

Answer 5

smell the smoke is it fishy if so check the trans fluid and if its down instal a tranny module a vacuum device on the tranny or is it black then its oil blowby from worn rings then use some smoke begone several times like every other week till it stops if not you need an overhaul like a cylinder regrind and new rings and thats called a ring job or is it gassy if so your missing some with your sparkplugs so check the plugs for color and clean or replace then clean the injectors if you have ahaines book on the car

Answer 6

if its blue smoking its burning the oil going pass the piton rings or bad valve guides or seals. just keep an eye on your oil level.try a couple of cans of engine restore,it works for a temp, fix.sooner or later you will need an engine or a car.Ive also seen where the transmission modulator valve goes bad and engine vacuum will suck the trans oil into the engine and this will make it smoke also,if thats the case replace the modulator valve,not real sure if you car has one.

Answer 7

Listen to all these answers except from the girl. Rings don't crack. Like all the normal people said, depending on the color of smoke. Either way, not a good thing. Sorry.

Answer 8

IT DEPENDS ON THE COLOR. BEWARE OF BLUE SMOKE SIGN OF BIG PROBLEMS. YOU MAY NEED ENGINE WORK OR NEW O RINGS... HAVE SOME GOOD MECHANIC PUT IT ON THE LIFT AND USE THE MACHINE. ALSO LET THEM DO A GOOD TUNE UP AND OIL AND TRANSMISSION FLUID CHANGE IF YOU ARENT DRIVING A SHIFT. GOOD LUCK. PS STOP EXCELLERATING THE ENGINE ALSO A NO NO IN COLD WEATHER

Answer 9

if it's blue smoke it could be bad valve seats or a busted ring on piston if it's white smoke it would be a cracked block or ahead gasket blown check with your mechanic

Answer 10

was going to say the rings could be cracked. also if you just added oil yourself you may have spilled some causing it to smoke more.