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

[Fran Blacker]

If you have an extra engine and interior ignition wiring harness make new harnesses. A 4' X 8' piece of plywood to lay it out with all soldered connections.

 

[toolmanmike]

You mention it seems like it might want to start when you let off the key. Id look at the ignition switch.

If not a dual ballast resistor, a switch sounds suspect.

 

[1 Wild R/T]

If not a dual ballast resistor, a switch sounds suspect.

Actually when you back off the key you cut power to Ign2, when the power is cut the magnetic field collapses which generates a single spark.... Pretty much proving you have power but the module isn't pulsing the negative side of the coil to trigger a spark... That proves there is power and ground and instead points to a bad module or pickup assembly...

 

[RemCharger]

I'm still stuck at the yellow wire from relay to BR.
Should be a brown wire from ign switch.
Check for discolored wires at ign sw connector as well

 

[WileE]

I didn't read through all the posts here, so I'll just add a tidbit to your initial post. I'd start at the bulkhead connector, be sure the connections are clean and tight ( years ago I recall a Ford Grenada with an electrical issue, I poked under and discovered the bulkhead connector wasn't seated tight ). Wiggle/jiggle all the wires from the bulkhead while engine running, could be an internal wire continuity issue. Check your ignition switch and it's wire harness, as well. Happy trails.

 

[1 Wild R/T]

I didn't read through all the posts here, so I'll just add a tidbit to your initial post. I'd start at the bulkhead connector, be sure the connections are clean and tight ( years ago I recall a Ford Grenada with an electrical issue, I poked under and discovered the bulkhead connector wasn't seated tight ). Wiggle/jiggle all the wires from the bulkhead while engine running, could be an internal wire continuity issue. Check your ignition switch and it's wire harness, as well. Happy trails.

And that is a very good point, most people wait until they have a no start to start wiggling hoping to regain spark.. But wiggling while it's running looking for a hiccup is much more effective...

 

[WileE]

A method I learned from an old timer over 50 + years ago. Electrical ? Ignore all those wires, check ONE system at a time, ONE circuit at a time, using a trace-back method. Find out WHAT that circuit is supposed to do, WHEN it's supposed to do what it does, and WHAT makes it do what it does. One at a time.

 

[threewood]

There is also the chance that one of the Packard fittings has pushed out of the plastic connector. Small needle nose pliers and push each one in. I had this happen on the circular ignition connector.

 

[MWbirdLOVER70]

With the trunk mounted battery? Did you run the negative cable all the way to the engine block? And what size cable? The longer run I would want a 1/0 for sure to eliminate voltage drop. Im leaning toward making sure every cable termination is tip top. Then start on every body ground per fsm and everything that may have added over the half century.
You mention it seems like it might want to start when you let off the key. Id look at the ingnition switch.
I know your invested in electronic ignition. But a dual point prestolite might be in my future.

Sure does remind me of ballast red but that too onvious. Pins under ECM harness or ECM harness not arching a bit?

 

[68 Sport Satellite]

It continues to amaze me how many people experience repeated failures of the MP/Chrysler Electronic Ignition & yet insist on still using it.... Throw that thing away before it strands you in BFE....

which one do you prefer instead? I've used the mopar chrome box since 2010 without issue. I've thought a few times about going to an MSD setup, but have read about countless random failures of those as well.

 

[Dennis H]

MSD. 20 Years. No hiccups, and their Tent at MATS gave Linda a free pair of ear plugs too.

 

[Kern Dog]

With the trunk mounted battery? Did you run the negative cable all the way to the engine block? And what size cable? The longer run I would want a 1/0 for sure to eliminate voltage drop. Im leaning toward making sure every cable termination is tip top. Then start on every body ground per fsm and everything that may have added over the half century.
You mention it seems like it might want to start when you let off the key. Id look at the ingnition switch.
I know your invested in electronic ignition. But a dual point prestolite might be in my future.

I have a 1/0 cable for the positive lead from the battery to the starter. There is a 4 gauge negative cable from the battery forward to the engine block and another from the battery to rear frame rail.
I mentioned that I did try another ignition switch. I've done that before with no change.

 

[1 Wild R/T]

which one do you prefer instead? I've used the mopar chrome box since 2010 without issue. I've thought a few times about going to an MSD setup, but have read about countless random failures of those as well.

I have a Pertronix III in the Green car, been there since 98... Yes, they like anything can fail... But how many do you heard about compared to the Mopar stuff? I know in the Mopar world more people run the MP stuff than the Pertronix.. But realize Pertronix gets used in Chevies & Fords... Plus tractors & just about everything else..

I run an MSD in the Red car, it too has been 100% trouble free... I have experienced the rusty reluctor issue they are known for but it never effected the way the car ran & I cleaned the reluctor...

FWIW I prefer the Pertronix... It looks stock, it has a vacuum advance & it always works..

 

[Kern Dog]

I already bought an electronic ignition kit from a member of this forum, it was an ebay buy from Rick Ehrenberg with a blue ECM that had Hi Rev 7500 on the side of it. I bought it and put it on the shelf, then got busy with Rich's Coronet 5 speed and then Dwayne's A/C so I haven't had the chance to mess with it. I don't rev much over 6000 rpms even though I do hammer it well within the 1500-6000 range!
I may give it a try and casually look into alternatives. I went with electronic when I first swapped to a 440 because other cars I had were reliable with the stock electronic distributors so I expected similar luck.

 

[Cheapsunglasses]

I have Ricks distributor and a Mancini box, I had luck with Mancinis box on my Lil red express truck so I put one on the GTX. I don’t think my 440 will live to see 7500rpm, but it’s seen 6500, and I can cruise at 70, put my foot down up a hill and get up to 100 without any hesitation or hiccups

I’m not a huge fan of msd because of the cost, but from what I’ve heard and read the new ones have the issues, the older ones are fine

 

[Kern Dog]

I've had points in this turd since I put the car together in 2005....

Granted, I don't drive it much and not far from home but I've never touched the points in 19 years. The car always starts and runs. Simplicity at it's finest!

 

[451Mopar]

I have had the issue where it runs fine once started, but usually only want to try firing when the key is released from the crank position.
I found my battery ground cable to the block was dropping voltage when loaded with the starter cranking the engine. Releasing the key, starter stops and less current = less voltage drop in the ground cable and the engine wants to fire. That is why i mentioned the two battery test.
Also, the other thing rotating when trying to start is the alternator. A bad brush holder or alternator could pull down or short the ignition power. Try disconnecting the positive power to the alternator field and see if that allows the engine to fire.

I didn't mention the usual troubleshooting items like checking coil, cap/rotor, plugs and wires, pickup and gap, as it seems you have already done that?

 

[Kern Dog]

I didn't mention the usual troubleshooting items like checking coil, cap/rotor, plugs and wires, pickup and gap, as it seems you have already done that?

I have in the past. I didn't yesterday. I just changed the ECM, wiggled the various connections everywhere, tested for power at numerous terminals, etc.
The worst thing about this is that it works or doesn't work for no apparent reason.
You know that when a 727 is slipping, it is going to fail. Brakes squeak or grind before they fail, engines will smoke or knock most of the time before they are done. This just fails then works again normally like a switch is flipped on or off. It never stumbles and sputters, it just doesn't fire, then it does.
The spray of starting fluid yesterday ...it was good to get it started but I want to know why it didn't. My limited knowledge of electrical systems has me curious as to what can either work or not work without warning.
It is easy to say "heat soak" but this has happened enough over the years to rule that out. It has happened on a first start of the day.
There are no burned or melted connectors in the ignition system.

 

[451Mopar]

The intermittent ignition problem I had was really frustrating. I think part of the problem is how the Mopar ECU detects the pickup signal. I think ground look problems (differences in the ground voltage levels) messes up the ECU trigger level trying to sense the pickup signal. Basically, the ECU can't detect the pickup signal when the high current cranking load is applied.
Most of my cars have been converted to multi-spart CD ignitions for the ability to drive a higher output E-Core ignition coil.

 

[Kern Dog]

Well now, THAT makes sense. If the system is sensitive to voltage variances and responds on or off dependent on that, it would explain it.