1966 dies after idling for a couple seconds

[romeo irey]

I have a 1966 thunderbird 390 and the car starts for a couple seconds maybe 2-3 and runs rough but then shuts off. It takes many tries to even get it to start and just dies I have replaced the whole fuel system and spark plague and wires. I replaced distributor cap and trimmed the engine and I just can’t get it to stay on.

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[seeker2736]

I have a 1966 thunderbird 390 and the car starts for a couple seconds maybe 2-3 and runs rough but then shuts off. It takes many tries to even get it to start and just dies I have replaced the whole fuel system and spark plague and wires. I replaced distributor cap and trimmed the engine and I just can’t get it to stay on.

Have you tried adjusting the Carb I just replaced my carb on a 65 and runs a lot better I bought a Street Demon and it bolts right on

 

[romeo irey]

Have you tried adjusting the Carb I just replaced my carb on a 65 and runs a lot better I bought a Street Demon and it bolts right on

I did make many adjustments to the carb with air and fuel and nothing worked.

 

[Ward 57]

I don't know if the '66s used a coil resistor but that could be the issue. Mine was intermittent and caused the same issue. If it fails no power goes to the coil except when starting as the start cycle bypasses it.

 

[Frankie the Fink]

A couple of quick things:

Start the car with the air cleaner off and observe the choke, make sure it starts to open
after the car starts. If not the engine will die from an overly rich mixture.

Check the feul pump , pressure AND volume (two separate tests) and the fuel filter...
Your car may be starting off the fuel left in the bowls and when the bowls
need refilled the pressure is too low to keep the car running.

Its a 5 minute check with a vacuum gauge- https://www.amazon.com/dp/B0006V2BS2/?tag=thunderbirdforum-20
the procedures are in the attachment for a typical vacuum gauge. Most vintage carburetors want at
leat 5-1/2 lbs of pressure to operate.

You replaced the WHOLE fuel system - does that include the carb ?

 

[romeo irey]

Yes that does include the carb and fuel pump and fuel lines. I removed and cleaned the gas tank replaced the distributor in whole and wires and spark plugs but occasionally it will shoot flames out the carb and I triple checked the timing and it was correct.

 

[Frankie the Fink]

If you are backfiring through the carb and timing is correct then I'm wondering about an ignition problem..
E.g. misfiring plug, bad ignition coil, etc.

 

[74 Harley]

How many mileage on the engine? It's beginning to sound like you need a timing chain. If you don't know how to check it I can post the procedure here for you.

 

[Frankie the Fink]

How many mileage on the engine? It's beginning to sound like you need a timing chain. If you don't know how to check it I can post the procedure here for you.

Valid point and would also explain the symptoms...