Voltage regulator and Ignition issues

Voeltagear

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Happy Easter! Cheers to new beginnings!

I've discovered a "new" problem with the 76 aspen. I thought after the engine was good and warmed up that I was having an AF ratio problem.
Then last night when putting the car to bed I shut off the head lights while backing into the garage. Suddenly it ran much better.

I mean it went from barely running and hard to apply throttle without flooding it to responsive and returning to the set idle.

I pulled forward and checked under the hood. It ran beautifully. I even turned on the headlights and no difference.

So, is it an alternator/regulator issue? Or maybe a ballast resistor/coil issue. I wasn't able to reproduce the problem in the driveway. But in hindsight, it's been happening after a drive of more than 20 minutes.

Anyone experience a weak ignition problem after driving for a distance? I'll keep my DVOM handy for the next time it happens.

As always, I appreciate any ideas/input.
 

BudW

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The voltage regulator and ignition module both are effected by a "possible / likely" poor ground. Some regulators use bare metal but many (as well as all ignition modules) use painted steel surfaces.
Paint (on regulator, on ignition module and on firewall) is an electrical insulator. Also rust/corrosion also is a poor electrical conductor.

Sometimes removing the two fasteners, taking a wire brush to the bolts, the module and/or firewall, will give you a good ground.
Also, making a short ground wire from one of the mounting bolts to firewall ground will also help.
20170803_114551 a.jpg


This has always been a problem sense these cars were built. A little elbow grease and a wire brush does wonders.
BudW
 

Voeltagear

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I cleaned up all the ground locations and connectors with a wire brush. I also found the "bullet connectors " someone used on the voltage regulator were quite loose. I'll be buying a new connector but I snugged them up for now. I'm getting 14.2-14.3 volts so that seems pretty good. It doesn't drop at idle. I'll monitor the voltage at the coil if it acts up again. Thank you all . I appreciate the comments and feedback.
 

Ele115

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You should be doing OK. Solder things whenever possible. Use copper conductors when available, avoid anything silver.
 

Voeltagear

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Update to my ignition issue. The car failed to start on Thursday a couple of hours after I parked it after work.

I measured the voltage at the coil and only had 1.2 volts. I checked the power at the ballast resistor and had 2.3 volts. The resistor tested at 5.6 ohms and 1.2 ohms. With the coil side disconnected from the resistor I had 12.6 volts. On a hunch I disconnected the Tachometer coil wire. The voltage jumped up to 6.9 volts. The car started and runs as it should.

Time to toss the old Tachometer.
 

Hayzoos

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Good hunch. Anything added to a circuit has to be included in troubleshooting. Hope it was the final fix for this issue.
 

Voeltagear

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Good hunch. Anything added to a circuit has to be included in troubleshooting. Hope it was the final fix for this issue.
A little more than a hunch to be honest. I noticed the needle drop while the engine rpm remained the same prior to the no start issue. Attention to detail.
 
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