Our 2002 Buick with the 3800c engine at times fails to start after running hard in 100 degree weather. Fuel pump has been checked out ok. Bleeding the Shrader valve on the fuel rail gives a flow of almost vaporized gasoline. not a stream of liquid. It appears to me the gasoline in the fuel rail vaporizes when the hot motor is shut off and the engine shroud traps heat from the engine and the injectors or maybe the engine computer cannot handle the vaporized fuel. Anyone from the hot part of the nation have a similar problem and how did you fix it. After the motor cools off, by the next morning it starts fine.

txgreasemonkey

. Change air and fuel filter, if this hasn't been done in the last 30,000 miles.
. Check for codes.
. Check/replace Ignition Control Module (ICM)--it may be breaking down when hot:

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. Check coil--it may be breaking down when hot:

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. Check Engine Coolant Temperature (ECT) Sensor:

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ECTs are thermistors, where the resistance drops as the temperature increases, providing key ECM data.

. Check Fuel Vapor Pressure Sensor:

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. Check MAF Sensor and MAP Sensor.
. Install colder running ACDelco spark plugs.
. Check cooling system.
. Use synthetic engine oil--you need the extra protection in extreme heat.


Even if you live in Las Vegas, you shouldn't be experiencing this sort of problem. Most engines love the heat. It wouldn't surprise me if the ICM is bad. AutoZone will test ICMs and coils for free. Remember, 90% of crank but won't start situations are electrical-related, not fuel.

CaptainRich

Based on what you've said, I think you may have a fuel vapor issue.

Were do you live? I'm in Florida (it gets HOT) and there are few problems with fuel volatillity. Have you tried other brands? No restrictions in the return line?

A simple test: pull the vacuum line off the fuel pressure regulator (under the engine "sight cover" and plug the vac line, a golf tee works great). Drive the car as you normally would, and tell us if there is any differance.

By taking the FP out of the picture, the fuel pressure will go up slightly (not to be concerned) and the excess fuel will go back into the tank on a return system, (or just get bypassed), thus allowing more cooler fuel from the tank into the lines. If this works, even slightly, then we're going in the right direction. Let us know!

Good luck!

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