Mopar 5 pin ECU troubleshooting

[67Dart273]

Here's some info I hope some of you can use, out of the 74 shop manual.

CAVEAT: This MAY and probably DOES only apply to the older 5 pin ECU, and not to 4 pin and or third party brands which may be different.

 

[Bulldozer]

i may have missed it, but the gap should be .008 with a non-magnetic feeler gauge?

 

[67Dart273]

Correct, I posted this for more like electrical, but good catch

 

[kursplat]

cool, saving this just in case...
on the other hand i'm lucky enough to have one of these...

 

[Bulldozer]

great info. i never could understand why they just didnt put in .008 right there with the "air gap" in the diagram. this along with your other half dozen electrical trouble-shooting posts should be sticky. ive tried to get them there but i have gotten no cooperation

 

[KitCarlson]

I just measured the resistance of four pick up coils, and found the resistances span from 295 to 300 Ohms. My meter is in calibration, with resolution to 0.1 Ohm. I wonder if early pick-ups had a higher resistance of 350-500 ohms.

 

[67Dart273]

I don't think that resistance is at all critical.

Kurspat, I would LOVE to get my hands on one of those, or at least a circuit diagram of one

 

[Bulldozer]

i measured one of mine just for kicks and got 460 ohms, if i did it right.

 

[kursplat]

Kurspat, I would LOVE to get my hands on one of those, or at least a circuit diagram of one

i'll crack the back open and see if it happens to have a diagram inside

 

[BillGrissom]

It would cause strange issues if the dual ballasts got swapped. 5 ohms in series with the coil would make it work, but not well. I know the factory wiring has keyed connectors, but people bugger with wiring and the keys could break off.

Also, the distributor connector seems to be an issue. I have found some pickups with a shorter male plug that barely touches (see my post w/ photos). I have read of people wiggling the connector to make it work.

I agree that people must maintain their existing systems, but I don't know why some retrofit their their points to the Mopar box when HEI is easier and better.

 

[Bulldozer]

It would cause strange issues if the dual ballasts got swapped. 5 ohms in series with the coil would make it work, but not well. I know the factory wiring has keyed connectors, but people bugger with wiring and the keys could break off.

Also, the distributor connector seems to be an issue. I have found some pickups with a shorter male plug that barely touches (see my post w/ photos). I have read of people wiggling the connector to make it work.

I agree that people must maintain their existing systems, but I don't know why some retrofit their their points to the Mopar box when HEI is easier and better.

what was the question Bill ?

 

[Snake]

Thanksssssssssss very much for the info boys.When I ordered my front engine and head light harness for the Dart I ask for one from a 74 Duster with the 5 pin.Nice to know how to trouble shoot on my own,till I screw up than its up to FABO to save my ***.Great thread. 67.