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

[MWbirdLOVER70]

Question in all seriousness. Is it possible that it fails when heated up and then doesn't fail when it’s cool? I know this is not in the same wheel house but I had a TV that would work great for 2 hours or so then just shut off. Turns out the solder connections on the board were cracked. I took the board out and stuffed it into my oven at 400 degrees for like 5 or 6 minutes long enough to reflow the connections. The TV worked flawless for 3 years up until I sold it to my brother. As per reading all over the web what I got was the new solder contains no lead and thats why solder joints are prone to cracking. Something about China cant Export Lead Soldered parts. Or something to that effect.

I’ve seen coils do that with windings and also on PCB boards that the solder joints reflowed (90 Daytona headlight module) but maybe the ECM module needs to be mounted in a cooler location but most Mopar people mount them on the firewall but my buddies dirt racer he mounts inside the car but that’s a more than likely place for getting damage

 

[DeltaV]

Question in all seriousness. Is it possible that it fails when heated up and then doesn't fail when its cool? I know this is not in the same wheel house but I had a TV that would work great for 2 hours or so then just shut off. Turns out the solder connections on the board were cracked. I took the board out and stuffed it into my oven at 400 degrees for like 5 or 6 minutes long enough to reflow the connections. The TV worked flawless for 3 years up until I sold it to my brother. As per reading all over the web what I got was the new solder contains no lead and thats why solder joints are prone to cracking. Something about China cant Export Lead Soldered parts. Or something to that effect.

Heck yes!!!

Troubleshooting of computer boards by spraying cold air on components can sometimes identify temp sensitive failures that are intermittent. More difficult to perform on a potted block of electronics. Place it on ice! Lol

Freeze Spray: Diagnosing Faulty Electronics

 

[MWbirdLOVER70]

Thank you, Dwayne.
I may have it figured out for now.
As always, my day starts much later than you guys. I online when east coast guys wake up.
I got out here and started to tinker.

* Fully charged battery, ether down the throat, Mopar Performance.08
ohm coil, orange ECM that worked in Jigsaw. No spark.
* Change back to previously used Accel coil. No spark.
* Mocked up spare new ECM plug and harness. Fire!!

From this:

View attachment 1752379

To this:

View attachment 1752380

I didn’t cut anything. I just disconnected the wire to coil positive and the blue/yellow to the ballast resistor.

View attachment 1752387

It is a bit of a rat’s nest but it worked for a test.

View attachment 1752388

The orange box of doom. You can see I “jumpered” the wires to the right side of the ballast resistor. Oddly, the diagram I got from Mopar Performance showed the following:

View attachment 1752393

Their depiction of the starter relay doesn’t match mine.

View attachment 1752394

They show the blue/yellow wire going to the relay.

View attachment 1752389

Mine is like that but nothing to relay

 

[toolmanmike]

Maybe Ray has a tester for your application?

FOR SALE - Mopar factory electronic ignition testers P/N 1-3500 NOS?

He does. He tests every module that he sells, new or used and he does sell testers.

 

[DeltaV]

He does. He tests every module that he sells, new or used and he does sell testers.

However, he doesn't have a tester for lean burn modules.

 

[toolmanmike]

However, he doesn't have a tester for lean burn modules.

Are you sure? What a waste!

 

[DeltaV]

Are you sure? What a waste!

I asked and he said no.


Then, he sent me a Facebook Marketplace ad link for one!!!

 

[toolmanmike]

I asked and he said no.


Then, he sent me a Facebook Marketplace ad link for one!!!

Smart guy, if you have to have one................................buy your own!

 

[DeltaV]

Smart guy, if you have to have one................................buy your own!

Imagine all the people that need theirs tested.

 

[Kern Dog]

Call it lowbrow but if you have other similar cars around, they can serve as test subjects for free !

 

[Don Frelier]

I think I would change to points before I made any effort to test or repair a lean burn system.
(And I'm not a points guy)

 

[Kern Dog]

I soldered in the only two wires that needed it. The harness already had the two wire plug to the distributor. The green wire is not needed for the two spade ballast resistor. That leaves a black with yellow tracer to the coil negative and the blue wire to the ignition switch.

I clocked the ECM to put the plug closer to the ballast resistor and routed the wires underneath for a cleaner look.

It is still a rat’s nest but I wanted to test fire again before I wrap it up with tape.

Then, I reached inside and….spin-spin-spin!
Son of a bitch….
I left the coil wire off! It starts up like it should. I’ll wrap it up tomorrow!

 

[1 Wild R/T]

Throw a screw in the center hole just to amuse those of us who remember Chrysler having done so...

 

[dadsbee]

Throw a screw in the center hole just to amuse those of us who remember Chrysler having done so...

And then it spins and spins and spins because nobody bonded the nut plate to the ECM...

 

[1 Wild R/T]

And then it spins and spins and spins because nobody bonded the nut plate to the ECM...

BTDT... Epoxy is your friend..

 

[GTXDAN]

I’ve seen coils do that with windings and also on PCB boards that the solder joints reflowed (90 Daytona headlight module) but maybe the ECM module needs to be mounted in a cooler location but most Mopar people mount them on the firewall but my buddies dirt racer he mounts inside the car but that’s a more than likely place for getting damage

Back in the late 70s my mom had a 75 Fury with a 318. It ran just fine until one day after it got cold outside and then it wouldn't start. I took her to work on the way to my job and we left it set. When dad and I got home and tried to start it, it fired right up. Next day same thing. We new it had something to do with the cold so next night we put a heat lamp under the hood and it fired right up next morning. Replaced the ECU and fixed it.

 

[Kern Dog]

I’ll check with ACE hardware fir a screw that will work.
This plug sure fits tight.

 

[1 Wild R/T]

I'm thinking # 8 x 1.25" Yeah, a new connector is snug, but Chrysler felt the connection was important enough to use a screw, I would play along...

 

[MWbirdLOVER70]

However, he doesn't have a tester for lean burn modules.

Remember those pesky things in wife’s 78 Volare bird

 

[MWbirdLOVER70]

View attachment 1752445

Imagine all the people that need theirs tested.

Pretty cool