I have a 1979 corvette hardtop, 1994 ZZ3 Chevy Goodwrench 350 engine. Car will run 15-20 minutes then engine dies will not start until cool down. After cool down will restartrun then same cycle. Recently replaced ignition switch and noticed ampmeter charges continuly even though battery is fully charged. I do not know if this charging problem has any thing to do with the engine dying. But it did not over charge previous to switch replacement. Any suggestions? Thanks.

 

Welcome to the forum daveboon, what type of ignition and fuel system are you running, sounds like the ignition is failing upon heating up, bad coil and /or control module. Also, as far as the charging level on the gage, if it's the factory gage you'll be reading total voltage of the electrical system, not amperage output from the alternator.

 

It actually sounds like a carb overheating problem. The fuel gets too hot and boils being so close to the engine and hood and not having enough air. I have heard of alot of C3s having this problem. You need to buy a carb heat shield. Summit sells them and Jegs probably does too. I will install one on mine here in a few weeks. What kind of carb and intake are you running? What kind of fan setup do you have?

 

78buckshot, thanks for fast reply. The engine has a new rebuildrochester spread bore / electric choke with electric fuel pumpand system pressure indicator. Carbdoes spray fuelwhilerefuseing to start after heating up.I fire through a GMC -HEI. I have tried three different coils includeing a newone and replaced the electric module with new one with same results. I ran a jumper wire from battery to distribitor to by pass the ignition switch but still would not start after heat up?

 

No fire on late 70's GM's will be module, stator, 12v supply to distributor, rotor, cap , or coil. You can check your stator (pickup coil) with an A/C voltmeter. Check across 2 wires while cranking. You should have at least .300 to .600 volts a/c while cranking. You can check thetach lead with a 12v test light to power while cranking to see if light flashes. If light is flashing, then module and stator are doing their job. These might give you something to start on. [8D]

 

79vetowner, I have a JET rebuild Rochester Q-jet on a lT1 manifold. Fan is stock 79 setup. Your suggestion sounds reasonable. It certernly would explain engine fault after heating up.I willtrythe heat sheild.Thanks.

 

Have you checked to see if you are losing spark?

 

I agree with mech259, it sounds like you are losing fire. Check the ignition system thoroughly.

 

I would deffinitley be looking for an ignition problem, if the Jones carb was spec'd for the car and is recent you wont be having issues with it.