I have a few of the barrel connectors I saved from older harnesses and I am pretty sure I have at least one, maybe two 1985-87 turbo power modules left from my original setup (sold the socketed LM).
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I have a few of the barrel connectors I saved from older harnesses and I am pretty sure I have at least one, maybe two 1985-87 turbo power modules left from my original setup (sold the socketed LM).
Not much of an update, but I got the car home today at least. I went over to where the car was so a coworker and I could push it to a better spot. I tried starting it and it started right up! So I had my coworker follow me to my house and at least I can fix it easier at home. Pretty nervous about it and I don't trust it until I can get to the bottom of this issue.
Anyways, definitely a wiring/connector issue I think. Still only the code 43.
I've been screwing around with this issue for quite a while now and my only conclusion is that I had not only one, but *two* bad power modules, as unlikely as that may seem. One seemed to be original to the car; one was from my parts stash. Every time the car would stall and refuse to start, the ONLY way I could get it to run again is by swapping the PMs. I did this for a few weeks bouncing back and forth between the two. Today, neither would work, so I got yet another PM out of my stash. This one had a reman sticker on it. Low and behold the car fired right up. I've looked into the wiring, connectors, tried swapping coil/HEP/entire distributor/wires and nothing else would 'fix' it unless I swap the PM.
I've heard there is a way to test the PM, or at least the ignition coil driver circuit without even opening the unit. It is the black/yellow wire, pin #1 on the 10-way PM connector.
Could you share I procedure? According to the 87 PM partial schematics of the coil driver https://drive.google.com/file/d/0B3q...1ReXRiVVU/view
Using pinout http://minimopar.net/ecu/pm-1985-turbo.html
I would test by attaching 12V to pin 2 and 4 and place ground at 9 or 10 at the 10-way connector. I doubt we need to connect the signal grounds on the 12 way.
Connect a test light from 12V to black/yellow wire, pin #1 on the 10-way
The test light should turn on/off when you touch the yellow wire, pin #10 on the 12-way. to ground.
Would I have to do this test with it plugged into the car? The thing with the PM connectors is that you can't back-probe them like a GM weather-pack connector since they are molded in. I would have to pierce the wire with probes while connected it seems. I surely could be wrong about the two PM failures....I've been wrong before. But I hate to throw them out without knowing for sure.
I'm so frustrated with the car I'm tempted to make my own harness and drop in a TIII and be done with it. Of course, that would be a whole new can of worms. That was plan "A" with the car when I bought it. Plan "B" was to keep it stock. I still like Plan B better since it's just so darn original.
open it up and inspect. look at the tops of the capacitors for swelling or leaks.
Let me ask the dumb question, are you still using the original coil or at least the original type? Coil failures were not an uncommon occurrence on Chrysler products, and a higher output coil would fry the older electronic ignition boxes.
Another item, those molded plugs were also known to lose tension on the female side and you are dealing with a 32 year old system. Is there and sign of discoloration due to heat on that pin location? They turn brown and eventually black from the heat produced by a bad or high resistance connection.
don't forget to give Chris at TU a nudge towards those super 60 harness he's mentioned making
that would lose the PM - which I've never trusted since I dropped the hood shut on my 86 and had the power module short and start burning
good thing I'd stayed in the garage and didn't go in the house in that moment
I haven't trusted a power module since
So far I've tried two different original Mopar ignition coils and I have a new NAPA unit in the car now. The PM plugs aren't discolored much, just a little off-white. When the car does run, I've tried wiggling connectors everywhere to see if I can track down a possible connector or wiring issue to no avail.
- - - Updated - - -
If I do go all-in with this car, I have a '90 Omni SBEC harness that I will base it on...
I believe I have finally found the problem. It was a loose connection at the logic module (red). I have no idea why changing out power modules seemed to fix it randomly, but after I took the kick panel cover off to expose the LM, I jiggled the wires a bit and it started. I could make the car stall just by pushing on the connector a certain way. I unplugged/replugged it seems fine again....for now. There doesn't seem to be any corrosion....just a loose fitting pin it seems.
Also, it turns out the car is sporting a Mopar Performance LM!
Seems to be a very common LM issue, not exactly sure why.
Some check every pin and connector but can't pinpoint the exact cause.
Some have to have the LM hanging in a certain position to make the car driveable.
Hopefully you will be the one to finally diagnose the issue!!
Thanks
Randy
Yeah, it was a relief when I could finally make it stall on-demand when I found it. Frustrating to say the least before that though!
I don't know if I can remove the pins from the LM connectors....maybe just slightly crimping them would fix it. Just unplugging/replugging seems to have fixed it, but I still don't quite trust it. So frustrating it makes me want to do an SBEC conversion.
The actual connector parts are available aftermarket, and if you need the secret to getting them out I have it. They are a tiny "double cantilever" spring connector. Contact cleaner is an excellent suggestion, also be sure the plastic water shield is in good condition and properly sealed to the harness, water intrusion has always been a problem on these cars.
A friends GLHS did this years ago. He had it running one night with it all pulled apart and it was cold so I was just sitting in the passenger seat in the driveway. I kicked the LM which was loose from putting different one's in and the car died. Cleaning the contacts and some dielectric grease cured it. I didn't recall this till you mentioned it though.
if you want to make your LM equipped car self driving pour some water in the top of the LM connectors
it should tool along at a nice steady 50 mph
lol .. in fact it WILL incest on driving at 50-55 until you shut it off
- yeah , a/c conversion L body cowel splash shield sealing needed a redo