Metro Won't Start when Warm

2000 chevy metro LSi (4 cyl- auto), over 111,000 miles. When engine is warm and parked for a short period of time (<5-15 minutes), like running into convience store - engine will not start easily. I have been able to get it started after several minutes of turning the engine over, an internal backfire, a strong odor of gas, and the next time, it starts. any suggestions? Starts perfectly when engine is cold. thanks

Smells like the engine is flooding, to me. To unflood an engine during cranking, hold the gas pedal to the floor until the engine starts. Let up on the gas as the engine starts.
Your mechanic can do a static fuel pressure check. If the fuel pressure falls off quickly after the ignition is switched off, a fuel injector is sticking open and flooding the engine. The mechanic will also want to check the engine coolant temperature sensor, and the idle air control valve, and other sensors.

Sorry for the delay. My bad. Computer crashed, mother hospitalized, etc… Thanks for the insight. Holding the gas petal to the floor does help about 50% of the time. I will take the car to my mechanic for the diagnostics. Thanks again.

I’m inclined to agree with Kit.

I want to add that if you have an injector stuck open it also provides an entry path for air and it can allow the gas to flow out the fuel line and back into the tank when you shut the engine down. When you try to restart the engine, you first need to refill and pressurize the line.

Normally, when you shut the engine off all injectors close and the gas is kept in the line (with or without a check valve) in the same manner as putting your finger over the open end of a drinking straw keeps the soda in when you pick it up, the same way a pipette functions in a chemistry lab. If an injector is stick open it’s like taking your finger off the straw. The soda flows out.

Try turning the key to “on” for a few 4-second intervals before starting if I’m right that should refill the fuel line and get some pressure in it. You’ll still need to replsce the injector, but it’ll at least get you started. Post back and let us know how you made out.

To hellokit’s list I would add a check of the fuel pressure regulator. The next time you stop someplace, pull the vacuum hose from the regulator and check for gasoline in the hose. If you find it, replace the regulator as it is helping to flood the engine by dumping gasoline into the intake.

To find the FPR look all along the fuel rail (where the injectors are) for a little canister looking thing with a small black hose attached to a nipple - that little black hose is the vacuum line to check.

ignition coil might be bad. you can have it tested at most auto parts stores.

I left the car with the mechanic for a week for them to investigate (as time permitted). Coils test: good. No Injector Pulse, no spark when warm. May need computer or fuel pump - or wiring problem. Chevy was contacted - and fuel pump is over $2oo (aftermarket) - computer more costly. I just stopped where it is - not worth pouring big dollars into. Junk it or sale for parts?

Thanks for all of the suggestions. I could never get to the bottom of the problem, so I sold it (with full disclosure) to a gentleman who repairs cars as a hobby. I have since moved out of the area and never learned how he resolved the problem.