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Discussion Starter #1
Need help with my 65 mustang fsbk it has a 302 8000 miles on engine new demon carb / fuel pump, pentroneix
distributor and coil car starts and run well but after it runs for a few minutes
it just shuts off as if I turned the ignition off will attempt to start but wont until it fully cools dowm
I have looked at every thing I can think of

thanks
 

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An engine only needs three things to run; air, fuel, and a spark. If it’s missing any one of those then no vroom vroom! Since you have nothing after it warms up, troubleshoot it at the most basic level. More than likely it’s lack of fuel or lack of spark... unless you have a raccoon wrapped around your air cleaner, it’s hard to block the air enough to get the engine to not run.

I’d put my money on an ignition component failing to function after it warms up... the ignition coil or the pertronix would be the first things to check If you have no spark. If spark is present than you are going to check if the choke is opening or if the carb is getting fuel. Clogged fuel filters let the car run for a few minutes and then cease to allow fuel through. After you let it sit for a bit the crud will fall down and allow fuel to flow freely... for a few minutes anyway and then it clogs again.

Check the basics and let us know what you find!
 

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For the engine to actually shut off as if the key were turned off, look at the ignition. It's hard to say if it's the igniter or the coil.
 

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after you check for spark look for a plugged tank

had the same issue drove me crazy for years. car would just shut off like the key was turned then restart 15 minutes later and run fine for another few minutes

I wasted a lot of $$$ on parts only to find my tank was full of junk. it would plug up then after car sat the junk would settle back down
 

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Discussion Starter #5
just converted car from efi back to carburetor fuel line is new replaced distributor and coil had problem
before conversion, getting spark because car tries to start momentarily, I am getting fuel, had efi fuel tank so tank was replaced. I was wondering if the ignition switch or faulty starter solenoid would cause this problem or if there is a resister located some where in the ignition system
 

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Is the spark strong? Blue and thick arc? Not red or yellow? If the ignition coil is failing (or the wiring that supply’s it power has added resistance) the car will spark but it could be weak sparks. If the pertronix were failing the spark would be strong but intermittent.

If your fuel system is as new as it sounds, it’s time to start checking voltages at the ignition coil and getting deeper into the wiring to verify voltages and resistances. A quick and dirty test... after the car warms up and dies, run a jumper wire from the + of the battery to the + on the ignition coil. If it starts, then you’ve narrowed down the problem, if it still won’t fire, then you eliminated the wiring to the coil.
 
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