Slant Six Stalling, Suspected Ignition problem

[Uber]

So, for a bit of background on the vehicle and what has been done thus far. About a year ago I purchased my first truck, intending to use it as a daily driver. It is a 1986 Dodge D150 with a 225 Slant Six. On its way home it overheated and I shut her off and towed her home. Since then she has had her radiator tanked, cleaned, and pressure tested. New coolant lines, a new water pump, a new radiator cap and thermostat. That fixed her overheating, during this we figured out it is a 1979 D150 with a 1986 body on top, everything technical is a 1979.
We put an emissions system back on it (to pass inspection, it looks good, but isn't really functional, its only a visual inspection.) and fixed its vacuum advance.
It developed an issue where it would loose power and buck back and forth when you accelerated to about 40 mph. We tried to (unsuccessfully) rebuild its holley carb, we eventually just bought it the same carb model but professionally remanned, we replaced its fuel filter and fuel lines. After this it would run, however at around 50-60 mph, it would suddenly loose power and stutter for a few moments, if you pushed it past this stutter it would clear up and continue driving normally.
Earlier this year, it burnt a coil out, after replacing it, it burnt that one out rapidly. We replaced the ignition control module and coil, and it hasn't burnt the new one out, it also got new plug wires.
This is where its newest problem started, it will start just fine, better than it ever has. It runs like an absolute dream for a minute or two, then it just shuts off like you turned the key off. This stall doesn't have any stutter or bogging down like a normal stall, it just shuts off. This is my first and only dodge vehicle, and one of the first in the family. We BELIEVE it is either in the distributor or the ignition switch itself. however, i would appreciate help from people much more experienced in the engine than I am.

The only remaining issues with her thus far are the stalling, and we don't know if her stutter at 50 mph is gone.

I will post pictures of her as she was when purchased, and as she is now.

The truck (We call her Green Bean) currently

Green Bean when we bought her

 

[67belevdere/225]

if it just quits like that , It could be it looses power 12v at the coil or module. a easy thing to do is a a light at the positive of the coil and try it like that and then , did you try a new ballast ?
its easy to do try that, if it was fuel it would slowly die out

 

[AJ/FormS]

After it stalls;
will it restart?
With what trouble.

I would do a spark test ASAP after the stall.
OOps treed

 

[Uber]

It has a dual ballast setup, neither resistor has been changed because they looked good and had power coming through them appropriately, though I could always try them. I will give that a try.

 

[Uber]

After it stalls;
will it restart?
With what trouble.

I would do a spark test ASAP after the stall.
OOps treed

It will start up just fine after a stall, though testing spark after a stall is definitely a great idea

 

[AJ/FormS]

It will start up just fine after a stall, though testing spark after a stall is definitely a great idea

Well that then sorta points to an intermittent power interruption.
If it's not in the Fusible link or bulkhead, I have seen loose connections on the back of the ammeter do that.

However; if the power supply remains solid, then I would test the pick up. Or maybe just do that first, cuz it's easier for sure than the other tests.

BTW. The two resistors in the Dual ballast block are not the same. That is why the connectors are keyed to only fit one way.

 

[Bewy]

Burned out two coils in succession? How did you test the coils to determine they were 'burned out'?

The 50-60 mph episode sounds more like carb flooding. Give it more throttle/air to mix with the extra fuel, & it comes good. Electrically, that would be more load on the ign & unlikely to be an ign problem.

 

[BillGrissom]

Not expert, but I vaguely recall that the dual ballast was used in the earliest electronic ignition. Later ones don't need the ballast resistor for the ECU module. I recall that later ECU's don't have the 5th pin, and in after-market ones the 5th pin is a dummy. Many posts here, so whatever they state. If a V-8, you could easily bypass all those concerns with the Ningbo $50 HEI distributor w/ integral ECU (ebay), but haven't seen one yet for a slant. Many here replace the factory ECU with a GM 8-pin HEI module and coil, which might be easier than fussing with your factory module, ballast, and wiring. That eliminates the ballast, so just needs straight IGN power, and is more modern (dwell control) so a stronger spark. I put that in my 1964 slant. Your existing distributor triggers it (get polarity correct). Many posts and TrailBeast here kitted new parts for those who fear junkyards (1985-95 GM V-8 truck).

Re fuel, when it won't run see if it will off shots of starter fluid down the carb, though sounds like an electrical problem. My suspects would be the bulkhead feed-thru terminals, key switch, or ECU ground. Run a separate ground wire, whether current ECU or GM module. Don't rely on the rusty sheet-metal screw like Chrysler did.