Heat. Having a fuel line to close to hot parts used to cause vapor lock in carburetor-ed vehicles. I don't think that happens these days with EFI, I haven't seen it in a long time.
could it be white vapor? If so its probably head gasket.
Could be a leak in a radiator hose, or radiator. ==Answer 2, Another Possibility== It could also be the radiator cap pressure relief valve action which vents coolant and/or coolant vapor to the coolant overflow reservoir/tank when steam is created in the coolant passages in the engine block. When the engine is shut off, the residual heat in the block can cause the additional pressure and/or steam.j3h.
That is the straight 8 engine, correct? Be sure the fuel filter is clean, the points are adjusted properly, the spark plugs and spark plug wires are in good condition. Vapor lock was a common problem back then. If everything else seems to check out okay and it only happens when the engine is hot, it could be a vapor lock condition. There were several remedies you could try such as wrapping the fuel line with aluminum foil where it runs close to the engine. The addition of an electric fuel pump is another option.
Yes, most vehicles have an on-board system to check for vapor leaks in the fuel system.Yes, most vehicles have an on-board system to check for vapor leaks in the fuel system.
Yes a 1998 mercury 200 efi outboard vapor can lock. Most of the time the issue can be traced back to the quality of fuel put into the engine that can cause the vapor to lock.
vapor lock happens the fuel boils in the line, maybe the line is too close to the engine, try putting foil around it.
Large vapor leak in the evaporative emissions system You could have a gasoline vapor leak anywhere from the gas cap to the tank to the engine.
dodge lancer vapor lock
yes it can cause smog test failure, check engine light will most likely pop up since it controls part of the vapor by filtering it.
Overfilling the fuel tank with gas could be a reason.
Are you in a warmer climate? Maybe a mountainous area. Is the engine overheated when this happens?If you answered yes to any of theses questions there maybe a vapor-lock in the fuel line.A vapor lock occurs when the fuel line runs too close to a very hot engine part, such as the exhaust manifold. The excessive heat causes the fuel to boil causing a vapor in the fuel line. this vapor blocks the line and no fuel passes.This is just one of the problems that may be occurring. More information on the engine temp and the weather when this occurs will help.
The year, make, model and engine size would help us help you. In older vehicles (pre-fuel injection) vapor lock was an issue.