Are you ready for a real weird one? Random NO spark from a MP electronic ignition system despite numerous parts swapped around...

[Geoff 2]

Either the bat is faulty....or there is a current draw on it after the engine is switched off. I bought a 50 amp one wire mini alt [ with built in reg ] for my car. I noticed after installing the alt, battery would discharge after a few days. The alt had some sort of leakage to ground & new alt fixed the problem.

 

[Kern Dog]

Do it again but first create a draw, open the door so the dome light comes on...

The battery is in the trunk, the trunk has a light in it. I can still open the door and try your suggestion just to take it further.

It is certainly possible that there is a draw somewhere other than the trunk lamp.
I have a 75 Power Wagon that would lose charge to the battery and need a jump to start after sitting 2 weeks. I think that I traced it to an aftermarket Voltmeter that I had wired direct rather than to switched power.

 

[dodgeboy440]

While I state with guarded optimism that this issue is solved, I was wondering if low battery voltage could lead to ignition failures.
The battery in this car isn’t old but hasn’t held a charge like it should.
12.6 volts is what I’ve come to understand as a full charge. The alternator will get this battery there after a drive but when it sits, it drops off.
I drove it Friday evening and it tested 12.63 when I got home. It now reads 12.25. This may have been going on awhile. There are times it starts up quickly even after sitting and even then, I could have been well under 12.6 and not have known it. It is only the extended cranking that the starter gets slower that tipped me off that the battery voltage was low.
I’m curious if the alternator charging up the battery has any effect on the ignition system. Is it possible that the low running voltage somehow leads to ballast resistor of ECM failures?

Good observation….
It’s proven in the new multi computer controlled vehicles that battery strength is required for proper functioning! Look at the dual battery setups in the new vehicles with the “ stop / start “ feature that shuts off the vehicle when stationary. Gee thanks EPA !
A move by the OEM’s to improve CAFE to appease regulators…. Duh !

I don’t think IMO that our vintage Hot Rods
Are as sensitive to voltage reductions but maybe someone from MSD / Petronix / Halifax Shops could chime in……

I would surmise our simpler stuff doesn’t have the electronic load the newer stuff does but it still requires a base level of juice to energize for operation.

Mopar2ya!

Nice Ride ByTheWay!

 

[bm02tj]

I never read all posts but did you replace the pickup in dist as I have seen that to be intermittent and it is cheap thing to try