How do you fix a car that over fuels?

Answer 1

Definition: Overfueling or "Wet Stacking" occurs when a Diesel Engine does not burn all the fuel injected. Usually accompanied by greenish or blue eye watering stinky smoke.

I suspect this is not what you mean, Read further down I cover Gasoline (Petrol) Engines later.

I the old days caused by allowing the engine to cool off while idling. All Heavy Diesel engines were prone to this. The Detroit Brand 71 series engine I primarily worked with were terrible for this. The Unburnt fuel washes the cylinder walls, pools in the exhaust pipes, and sprays all over the Stacks (tall exhaust Pipes on a Highway truck).

On more modern Diesels the issue is a mechanical or electronic failure. Usually caused by Unit injector problems on a common rail system or Low fuel Pressure on the common rail.

Over fueling on a petrol engine is more commonly known by degree of severity where I race.

Rich: a slight excess of fuel that is safe for the engine but costs power and fuel economy,

Very Rich: The engine runs but has easily noticeable or large amounts of black smoke out the tail pipe, has gasoline accumulating in the oil and will quickly damage the engine.

Flooding: A situation where the engine is fed an uncontrolled amount of fuel not allowing it to start or run. Usually caused by a failure in the Carburetor or fuel injection system

Rich requires a "Jetting Change" on a carburetter engine. There are several You tube tutorials on this as well as many manuals, I still use my Petersons Tuning manual I bought in the 1980s On Injected engines just a re-tune on the computer.

Very rich failures on Computer injection stuff usually is traceable to a bad sensor or

Fuel pressure regulator failure. Carburettor engines 1st look for leaky, sticking or worn needle valves, sunk floats, and 1st thing to check on a high performance engine, fuel pressure! Most race or very high performance engines have to have the fuel pressure regulated. To High pressure will mess every thing up. Low fuel pressure just causes the engine to explode. So it has to be right!

Flooding: Same as very rich