Motor shutting off intermittently

[Honda01]

It must be an ignition problem because the tachometer does go to zero. I have a MSD ignition multi spark discharge. It says MSD 6a. Could it be in that? All the wires look clean and corrosion free.

 

[Honda01]

In addition I did change the ignition and tumbler to make sure it wasn't that.

 

[DirtDonk]

It must be an ignition problem because the tachometer does go to zero.

Good to know. That's a dead giveaway.
Also, the fact that you do have a tach, means that for testing purposes, you should actually disconnect it!
The reason being, since it's integrated into the ignition system, if there is an internal fault with the gauge itself, it can cause the engine to die.
Same for the little radio noise suppressor choke. If you have a little metal cylinder looking thingy connected to the positive side of the coil (or to any other wire in the ignition system for that matter), disconnect that for testing too.

I have a MSD ignition multi spark discharge. It says MSD 6a. Could it be in that? All the wires look clean and corrosion free.

Unfortunately, yes it can be the problem. I've never had one go bad, but there are a ton of people here on the forum that won't use anything made by MSD anymore because they've had too many failures of their 6-series modules. With Broncos, you can't ignore the possibility that there is some fault with their wiring in those cases either, but there are too many failures to ignore the possibility of the equipment being short-lived.
As said, plenty of us using the stuff with no ill effects, but as with any electronic device, just about anything can go wrong. An internal break in the wires. Internal component on the verge of failure, so when it gets hotter after running, it "temporarily" fails.
And yes, most people consider electronics to be either working or not. But I'm pretty sure we've seen a few of these modern miracles give intermittent issues.

Not likely to be the ignition coil in a case of a CD type (capacitive discharge) ignition though. The coil doesn't have to work as hard, or get as hot with this type of control module, so is likely to last longer. But if given an older coil already, that would still be a potential culprit.

In addition I did change the ignition and tumbler to make sure it wasn't that.

Yeah, not likely to be the tumbler. It's just a simple stud turning in a hole. And a completely non-electric part of the system. So very unlikely to ever cause an issue like this. As we've learned here over the years, almost nothing is impossible with a Bronco(!), but it's still unlikely to be that particular part.

Which distributor again? You might consider bypassing the MSD box to see if things improve. Depending on the wiring and other components, that might be an easy thing to do too.

Paul

 

[f1drivr]

Replaced the Module and new Resistor the problem is still there! Guess ill pull the fuel lines.

Well, I disconnected the fuel vent lines at the tanks and removed the gas caps. It ran at idle for about 40mins. With no issues. I was unable to drive due to the weather but that seamed to have been the problem.

 

[Honda01]

So here's the latest. I replaced the coil with the new exact same replacement. It will go about 5 miles further before shutting off. Start right back up able to get home but still about 3x so it will shut off before I get home.

 

[DirtDonk]

Any chance of a wider shot of the engine compartment? Looking for general condition of the wiring.
I know you said it looked good, but sometimes this stuff hides in the most innocuous places. And besides... You've already replaced practically every component that could be at fault! Except for the ignition control module (the 6 box).
Gettin' to be an expensive search.

The main chassis wiring looks original. Plenty of room for error with the interfacing of old-vs-new on these rigs.

Paul

 

[Honda01]

So here's what I ended up doing. Changed the ignition box and that didn't work. Got to looking more at the alternator and regulator. The alternator seemed fine at first but then after further inspection it would only put enough juice in the battery only to keep it going. When I bring it to 3000 rpms it still would not register over 12.5 volts. So I know it should put in about 14 14.5 volts . I went and change the alternator and the voltage regulator. So far about a 20 mile drive and it runs just fine keeping my fingers crossed for the next 25.