Igntion issue - '66 dies after about 5 minutes of idling
I have a '66 Fastback, 289, accel plugs, coil, plug wires, pertronix ignitor under the distributor, new starter, solenoid, fuel pump, lines and tank. I drove the car the other night, ran great. I Shut it off and got back in 5 minutes later, started it up and it died after about 10 seconds. No sputter or anything, just like someone shut the ignition off. It started back up after about 10-15 sec. of cranking. Got it home, no issues. The next day before my drive I turned it on and let it run for about 5 minutes just to be sure it would not die again. Sure enough, it shut right off after 5 min. or so. This time it would not start at all. Cranks hard. It is getting fuel. I swapped the coil and pertronix ignitor....still no luck. Would a bad ignition switch cause the car to run for a short time then die like that and then not start at all? Thanks for the help in advance!
I have not tested anything yet, but the engine cranks hard when I turn the key. It is acting like it is not getting spark. The engine was no where near operating temp after 5 min. of idling the second time it died.
I have now changed the ignition switch. It fired right up and then died after about 5 minutes of idling. Have not been able to get it started since then. I am now thinking it could be a wire issue. When the key is switched to the "on" position, the positive side of the coil should be getting power, right? No power here.
In the start position, the coil should also be getting 12v from the starter solenoid, a source separate from the "on" position. This one's going to be difficult to locate. Perhaps you have a short in the wiring to your pertronix?
Had similar symptoms on two engines of mine. Both times would run 5 or 10 minutes and that was it. No spark for a while, then when cooled down I could run for 5 minutes or so and it was doneski again. Was a bad coil each time.
I know you've replaced the coil, I hate to say it but sometimes new ones are not always good ones?? Try swapping your coil with a known good working one, at least you'll eliminate a possibility. Another idea is swapping back in a set of points, at least until trouble shooting is done, then you can discount the Pertronix being an issue. Just some ideas... good luck.
67 Fastback GT -- original colour (Frost Turquoise), orig engine, .. . 1st pic is the car as it now is. Stock except for Opentracker roller perches and idler arm, roller bearing pedal cluster, Cibie lights, radials, that sort of thing..
2nd pic is of me and the same Mustang - May '67, with original F70-14 Wide Ovals.
I had a similar problem with a 74 Bronco years ago. Someone suggested I had a wire shorting out. It was the coil wire that gets the 12v when you turn the key on. Way I pinpointed it was to start it when it's dark outside.....and started wiggling wires under the hood....saw the wire arc on the intake and found my problem. I know it's a long shot, but might be worth a look. I chased this problem for a couple months.
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Red66GTCoupe, I am wondering the same thing. I had the ignition wiring diagram out and the one wire that goes from the ignition switch to the coil, #16 Red-Green, could be the problem. I just have to trace the stupid thing back through the firewall. The wire that is connected to the coil is not original. Could take some time. If it is bad, do I have to replace that entire plug of wires?
I am considering rewiring the entire car this winter.
The wire from the ignition switch that ends up at the + side of the coil is a resistor wire which is intended to drop the voltage down so as not to fry the points. That is with the key 'on'.
While in 'Crank' the solenoid switch delivers full battery power for starting the car. When the key is released it is in the 'run' or 'on' position and feeds voltage (@7-8v iirc) to the coil.
As indicated above, somewhere in that wiring harness you're losing spark.
When it stops, check the post on the solenoid ( ign) for power at that wire while cranking. If battery voltage is there and there isn't at the coil + terminal then you know it's in the harness.
I also agree with jfstang that you might have two bad coils in a row.
Check those and get back to us......regards....John
I will swap coils again today. I will buy a stock one and the Accel that I have on the car. Would there be an underlying cause as to something killing the coil or would it just be that they were bad coils? In regards to the wiring being the issue, would the car be exhibiting these symptoms (Dying after 5 minutes, like clockwork) if it were a short in the wire?? I have a manual choke carb, but come to think of it, the car was smoking pretty bad after it ran the last time for 5 min. Thank you to all for their input!!
Everyone is on the ignition track.
What about the fuel track?
If after 4 minutes, you rev the engine slightly for a few seconds, does that reset the clock to ZERO and give you another 5 minutes, or does it die after 1 minute?
If it resets the clock, then the engine could be too rich at idle and loading up. That would explain hard starting after it dies...it's flooded.
Check the voltage regulator.. and your voltage. All you need is a regulator going bad, and it will cause the problem that you describe.
I bought a new one wire alt. and have not yet installed. My autometer volt gauge always reads very low. Sometimes at cruise it will read 11-12 volts, but lately it reads no more than 8-9. Should I try installing my new alt. first?
Regarding the fuel question, the car has been sitting for over a day now with no attempt to start. The last time this amount of time elapsed without an attempt to start, the car still did not start. Still thinking a flooding problem?
Is the fuel cap vent OK? If not there will end up being a vacuum in the tank and it will fuel starve after a few minutes.
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