Car dies while driving...no power at all.

[Canty]

Today I had to jump start my car. The battery tested bad at work but still took a charge so I kept it because we didn't have the battery I wanted. On the way home I was driving and everything was good. Then the power began dying, lights were getting dim. I was on the final dark straight stretch and there was a loud "pop". I am about 90% sure I saw a blue flash on the driver side during the "pop" but I am not sure. Then the car back fired and all power is gone. Absolutely no electrical power at all.

Some back ground on this car: I recently put in an external voltage regulator that was over charging my battery. 15 volts. I also have had the fuse blow that runs the instrument panel lights twice in about 2 weeks.

Does anyone have any idea where I should start?

[tryingbe]

Dead alternator...

[NAJ]

External Regulator?
Power Module was shown to be faulty causing your original overcharging issue?
Sure you did not have a problem with the field control circuit being shorted?

If you heard a "pop" and saw a "blue flash" you probably blew a fuseable link so all of your issues are caused by excessive amperage.

Get out your volt/ohmmeter and start by checking the fuseable links.
Once you find the one that blew we will go from there.

And...
Exactly what are we working on???

[Canty]

1987 Carb Omni. Ya, I just replaced that alternator but I tested it and found it wasn't charging properly.

NAJ, I will be testing the fusible links like you said but how do I test these..."Power Module was shown to be faulty causing your original overcharging issue?
Sure you did not have a problem with the field control circuit being shorted?"

I worked on Sikorsky helicopters doing electronics and avionics for almost 9 years and I didn't have as much trouble with those as I do with these L bodies!

[NAJ]

If this is a carbed car it already has an external voltage regulator, only the injected cars have computer controlled charging systems.
You would have a spark control computer and a normal charging system, your vehicle would not have a power module and logic module.
I have to go find the wiring for an 87 carbed car,which may be rare, 87 1/2 was when the last of the carbed cars rolled off of Chryslers assembly line.
86 should be the same.

[NAJ]

Found the wiring.
I will PM the wiring to you.

There are 3 fuseable links that are involved in the charging system.
If one blew it will be soft/mushy but you will see no external damage to the insulation.
You can use an ohmmeter to check continuity thru the fuseable link(with battery disconnected) or use a voltmeter, you should have power in and out of the fuse link, a blown link will have no power out.

The fuseable link is designed to prevent meltdown of a circuit if amperage flow increases above what the circuit is designed to handle.
This usually happens when the circuit/component is shorted to ground.
Once you determine which link blew we can then trace that circuit to determine what happened and correct your issue.

Normal charging voltage for this system is 13.8-14.3 @ 80 degrees.
Charging voltage increases as temperatures decrease so you could be at/above 15 volts if you are near 0 degrees.

[Canty]

So today I took apart the wiring harness. I cut off all the loom and black tape I could see. I didn't find anything that jumped out at me as being wrong. The fusible links by the shock tower all check out to be ok. The only thing I saw bad was the grey wire going to a relay on the drivers side fender. It was a broken wire at the positive wire where it junctions into like 6 wires. Just for grins I put the battery back in and gave it a shot...fired right up! I left it running and grabbed the wires and shook the harness...no pops no sparks and I didn't get shocked. So I'm clueless about this gremlin!

[NAJ]

So you got the car to start...
Did you replace the faulty battery?
If so...
What is charging voltage?

[Canty]

I am going to replace the battery today when I get to work. I will also check the alternator on our bench tester and see what's going on with that as well.

[Canty]

Battery tested good, alternator tested bad. Maybe the flash I thought I saw was backfire through the exhaust? Idk. Either way ill install a new alternator and do more tests. Btw...I'm still looking for a nippondenso alternator bracket. If anyone has one let me know.