Ignition Cutting out--Round up the usual suspects

[PatrickH]

Ladies and gentlemen, I have a confession to make. I am a professional technician. Unfortunately that means the shortcuts I would not take with a customers car, I  took with my own. My 86 Eagle started a stalling, cutout, ignition dropping out recently. Around town, I would stall or cut out extremely frequently, once on the highway, not so much. Coming into town it cut out, stayed out long enough that when it came back it blew the seam on the muffler so that the edges were 12 inches apart! No problem, probably just the ignition control module, Swap in the part.  At first, seemed like the "shotgun fix" fixed! No, it came back. Boy, that sure feels like a module or  pick up coil cutting out,well, I will replace the pick up coil. Nope not that one either. Coil? Nope not that one either! 
OKAY, NOW it is time to stop being such a weeney and do some REAL Diagnosing! (that is what I get paid to do, so now I better start doing it!) I keep staring at the wiring diagrams thinking something is not right. I stop for some Ramen noodles and thinking time. (already had a 10 hour day)  The part of the diagram that bugged me -
was the ONLY ground for the entire Ignition System was thru the distributor! I checked from the black wire at the module to the battery----- 230 ohms of resistance. I tapped in an additional ground, ran it to the fender...
Mission control we have Ignition! And a steady & reliable ignition for 90 miles so far! Thought someone else might need  the info about the ground, hope it helps!

[carguy87]

Already taken care of.  Most of us also run an additional ground wire to that little infamous grounding point on the bulkhead just south of the windshield wiper motor.  I like being on the safe side and ran one to my Alternator housing too just for good measure.

[tougeagle]

Already taken care of.  Most of us also run an additional ground wire to that little infamous grounding point on the bulkhead just south of the windshield wiper motor.  I like being on the safe side and ran one to my Alternator housing too just for good measure.

I'd consider this to be some good diagnostic advice for the many that still don't know about it (I never knew though it no longer applies to me)

[Jurjen]

Yes, that is good information.

Not working on your own car being a car technician is also normal.
My son is working at a tire centre and in the winter time they sell snowtires like hot cakes.
Not one of his co-workers is putting snow tires on there own cars: too busy or sold out or whatever excuse you can think of.

[IowaEagle]

Yeah, that little ground wire has been a problem after a few decades.  Good to run an extra one for insurance.

[amcconcord]

Hello;

I am stuck in PA, and my little lady [wife] is having a problem with her 1981 Eagle, it starts on a dime, runs at the right temp and all, but when it gets to temp, it craps out, [i.e. stalls], there does not seem to be by what she tells me a fuel problem. Though her way of fixing it so far I disagree on, she rides the gas pedal and brake, keeping idle speed high at stop lights and such, don't like that but I am here and she is way north of me and needs the Eagle to get to work, and around the Island. Where is this ground wire you speak of? The module is next to the battery passenger side wall? As a engineer I know for a fact, the higher the amps put out by a faster running alternator and at or around 13.5 volts, the resistance of 230 ohms could be decreased, because higher output, allows voltage AC or DC to travel further, thus at idle resistance increases as output decreases, thus no spark, no start! Doug your good  with pulling drawings from thin air, can you shed light on this matter for me, or what else she might look for.
amcconcord-2

[PatrickH]

Just go to the 4 wire connector from the ignition module, and look for the black wire. They may all look black under the dirt, but they really are different colors. I tapped into the vehicle harness side of the connector right there and ran a 12 inch wire to the fender ground. You could also as easily put it to the battery ground. It should be black on both sides of the connector. This wire goes from the Ignition Control module to the distributor. The ground goes thru the pick up coil in the distributor and has a ground screw into the distributor housing and gets its ground from the distributor housing to block mating surface. Mine was worse hot as well, and idle stall was the first symptom to develop. Hope that helps.

[amceagledude]

my 86 eagle is doing this same thing. stalls after about 30 minutes of driving and worse on hotter days. when it stalls it starts right back up again and seems to run better after the cut out. im just learning and trying to do what i can on this car without going to a shop for everything. i changed the icm box but not the pick up coil yet. did you "splice" the the black wire like a "Y" and run a wire to the fender ground of the car? im a little confused. the four colored wires connect to a connecter from the vehicle with three colored wires green, yellowish- green and black. i believe thats the side i should tap into from what you said right, not the ICM side? 
the pick up coil looks as if it is the original from '86. should i replace the coil or try this grounding thing that worked for you? thanks so much for your help and sorry for the beginers questions!

[PatrickH]

I would add in another ground by splicing into the vehicle harness near the ICM connector. solder and heatshrink for a good weather proof connnection, and run it to battery or chassis ground. I would try that first, before replacing anything.

[luvmyeagle]

What gauge wire is the ground?  And do I need to replace the whole wire from the distributor or is splicing into good enough?  I think I have 8 or 10 gauge wire laying around.  Can that be used for the ground?

[PatrickH]

For the ignition your good with  14-18 gauge. It really isn't that heavily loaded a circuit. Heavier is fine, just sometimes more of a pain for splicing.

[luvmyeagle]

For the ignition your good with  14-18 gauge. It really isn't that heavily loaded a circuit. Heavier is fine, just sometimes more of a pain for splicing.

I was thinking of upgrading the wiring (+alternator to +battery, -battery to chassis and chassis to engine block) to 8 gauge wiring.  I've noticed the headlights dimming when braking at night.  Is this worth it?  I've heard of people doing the Big 3 with 0/1 gauge wiring but that's a little over killing for me since I don't have a power hungry stereo system.

[PatrickH]

4-8 gauge for those heavier applications is usually sufficient. Might do a voltage drop test on the existing connections to see if you have high resistance. Voltage drop is measured with the circuit loaded, Digital multimeter, but you have the leads on the same wire. Have the scale set on low (.oo1) then put one lead on each end of the wire while the circuit is loaded. This works for power or ground. Rule of thumb, .5 volt drop to 1.0 on a very heavy circuit ok. Most circuits, if voltage drop is over .5 you have high resistance in line. Voltage drop is truly measuring deliverable voltage rather than an ohm test. Clean all connections, look for green or white on the copper strands. Clean block connections as well.