Okay, 1976 F250 4X4 360 V8 and C6 automatic.
I know I've been going about this in the wrong way by just throwing parts at it, but I don't know how to diagnose this problem.
The truck runs like a scalded dog for 3 minutes at a time. And then it shuts off as if you flipped a switch. You let it rest for a couple minutes and then she'll fire right up, but you have to let her sit for at least 2 or 3 minutes.
I've replaced the voltage regulator, pick up coil, ignition module, ignition coil, ignition switch, fuel pump, and I'm at a lost.
I need y'all to dumb it down so a back woods hillbilly can figure out if I'm loosing spark or fuel.

Thank all of you geniuses for your endless knowledge and help.

 

You need to test the ignition coil resistor wire from the switch. Make sure its present and not burned up. Then test the red and white wires on the module for power. Do these tests when you start it and after it dies. I would guess defective coil or hall sensor.

 

Loss of fuel delivery would make the engine "sputter" before it dies, you state the engine cuts out like you flipped a switch, so it's obviously electrical.

The fact it starts up again after resting points toward it being a heat related failure. Most electrical components can spec out good when cold but fail when they get hot.

Just because a part is "new" does not make it good, particularly electrical parts. I agree with ford390 above, I would test the ignition coil and pick-up coil, before and after the engine dies.

 

My thought exactly, but how do I test this to figure out what the problem is?

 

To test the pick-up coil check the resistance between the ORANGE and PURPLE wires of the pick-up, it should be between 400 and 700 ohms, check it cold and also right after the engine cuts out.

At the moment I do not recall the specs for the ignition coil but I am sure someone here does.

 

That's always my problem flatbedfordguy. I've read them hundreds of times over the years, but I never remember the ohm range on a coil. Of course, any time you change that original coil for an aftermarket, the test results would change too. So we would need to know exactly what coil you bought Aaron.

One long-term poor running and no running issue was finally resolved here as a faulty wire to the ignition control module. The original one had just finally failed to give consistent power. Could be the same with yours.
With a volt-meter you can test running voltage at the battery with the engine running to make sure the alternator is putting out correctly. You should see 14.5v give or take a few tenths. Then you can read the voltage at the positive side of the ignition coil while it's running to get a reading there too.
If it's 12v when cold, that's ok, but if it does not go down to 6v to 8v fairly soon, the resistor wire could be what's causing your coil to overheat.
If the alternator is putting out more than 14.5v such as 17v or so, then it could literally be cooking things while it's running.

These things may not in themselves direct you to the one culprit in all this, but they are good things to know and may help give you a direction.

Good luck.

Paul

 

All of the parts I changed were a NOS Motorcraft parts. I still need a step by step for where to start and where work back from to figure out where I'm loosing my spark.

 

I also did check the Alternator and it's putting out exactly what you stated.

 

The pick up coil tested good.

 

Since it runs sometimes, and does not seem to change it's timing after it stops and then runs again, I think we can rule out any problem with the distributor's gear and/or roll pin attachment. So the rotor is spinning in it's consistent style.
Check under the cap anyway, just to make sure there is at least one screw adjacent to where the wires enter, fastening the assembly to the body of the distributor. This is the Black ground wire's attaching point and helps consistency on older engines where the distributor's aluminum body does not have a good connection to the engine block. Oil, rust, and all that "old age" stuff sometimes gets in the way.
If the screw is there attaching things, we can work our way back to the ignition module and it's wires.

The modules themselves do fail intermittently sometimes. Usually either a do-or-die thing, sometimes they're intermittently heat related. Have a jug of water handy and the next time it dies on you, pour water over the Dura Spark box and see if it fires right back up. I think you said you normally have to wait awhile for it to run again (typical heat-related thing) so this might be a good test.
If that does not pan out, do the same thing to the ignition coil and pour water over it.

I know those things are new, but they still have to be part of the testing so you don't get blindsided by one of your new parts having the same problems as the old.

All wires must be checked with a volt meter and tested while moving the wires around by hand to make sure there is not an intermittent break.
1. When the engine dies, do you still have voltage at the positive side of the coil? If so, how much?
2. When the engine dies do you still have 12v at the Red wire in the 2-wire connector at the module? If so, how much?
3. When the engine dies, disconnect the radio noise suppressor at the coil. Do you still have one of those connected? They can fail strangely and cause trouble.

And while I'm mentioning colors and numbers of wires, what color module do you have in that '76? Color goes by the wire strain relief, or "grommet" where the wires come out.
And are there two, three, or four connector bundles on your module?
Just checking to make sure we're all on the same page.

Thanks

Paul

 

just a quick comment; "Dust Off" or equivalent keyboard cleaner is COLD and a great way to help diagnose heat/cold issues. Helped me diagnose a Crane ignition system once that would fail only when thoroughly heatsoaked and idle for a few minutes... could drive anywhere hitting on all cylinders - until you hit a long light, at which point it turned into a three-cylinder.