Geo Metro refuses to start when warm

1997 Geo Metro - Starts great when cold. I can go to the store and when I kill the car, it may start if I start it again within five minutes. Maybe not. Normally, it will not start for 30 minutes to four hours. We have replaced the fuel filter, distributor cap (It’s getting fire). We pulled off the breather and we are getting gas from the gas line to the carbureator and gas is going freely out the return. When the car will not start, the carbureator is dry EVEN THOUGH there is gas running freely in the gas line to the carbureator. We checked all gas lines and vacuum lines. Sometimes the car starts before the car is completely cooled. Other times it must cool off entirely before it even considers starting. What on earth is the next step and what is holding up the gas between the fuel line and the carb? Helpppp!

Jeez, this must be the last carburetor car made. Most every thing after 1996 is EFI, to be compliant with ODB-II standards.

These late model carbs have a fuel shut-off solenoid to prevent dieseling. It is possible that, with heat, the solenoid is sticking. Also, there should be a solenoid to control the bowl vent. If this solenoid is stuck, it could cause over-pressure in the float bowl, causing other problems. Check these first.

I am guessing from your description that the ‘carburator’ on this engine is a throttle body injection carb. If you are not getting spray from the injector while cranking, you are going to have to find out why the computer is not pulsing the injector. The usual culprit is the crank position sensor. But, if you are getting a spark while cranking the crank sensor is probably working.

As a diagnostic step you might try squirting some ‘starting fluid’ just before cranking. If you get a catch and die, you know that it truely is a fuel problem. Check the power supply to the injector. If that is okey, get back to us with your results.

Maybe we can help further.

Nope, no carburetor. The car has throttle body fuel injection.

I’m going to guess that heat soak from the engine is causing an electronic component or even just a connection to get flaky. Time to try to narrow down the possibilities. Start by testing for spark, then fuel using staring fluid as Researcher suggested.

We did squirt starting fluid before cranking. It catches and then dies occassionally - doesn’t catch at all occassionally. I will try to find a meter to check the power supply to the injector and will post my results. Thanks for the responses. A local mechanic kept the car for two weeks and said it was possessed. I appreciate any ideas.

I’m leaning towards a spark problem (See me lean?). You’ve fed it gasoline, and it doesn’t want to run. It’s time to use that handy dandy repair manual and check some sensors with a voltmeter (electrical multimeter).
The crankshaft position sensor can have odd electrical behavior when it gets hot from engine Heat Soak. Check its ohms when the engine is hot.
The ignition module and the pick up coil need to be checked, also.