Every once in a while, I'd notice (especially while driving at night) that I get a surge/spike of electrical power in my Challenger. (`71 383-4spd) I never paid much mind to it since everything has been working well otherwise and it didn't happen very often. (not to mention I'm lazy )

Although, it just started happening more frequently such that I can actually watch my volt gauge for about 5 to 10 seconds and witness the jump. It'll go from 14 volts (whether at idle or cruising, doesn't matter) and see it spike to around 18 volts, and then immediately go back down.

Two days ago I went to take the car out to run an errand. I fired her up and it konked out after a few seconds of running. This isn't uncommon since I don't run a choke and I wasn't giving it much gas. When I went to fire it back up, there wasn't ANY power. No electrical juice to the horn, lights, my auxiliarly fuel pump, etc. I sat there for a moment and then tried again. Power was back on and she fired right up, but now the volt gauge was going from 14 to 18 volts, up & down, up & down faster than it ever has before. I kept it running for about a minute and it finally settled at 14 volts.

I decided against taking it out since I didn't feel like possibly melting wires and getting stranded.

So, my questions are: What could possibly be causing these volt spikes (regulator? alternator?), and is the recent loss of all electrical power possibly connected/related?

Thanks in advance for your input, guys!

Dale

bad connection or bad ground at the vr.
I had a bad connector to the voltage reg that made it burn out a battery because it spiked so much.

I'd start with checking the ground connections negative battery, body grounds, and clean battery posts as well. Voltage spiking to 18 volts seems like you are losing connection to battery intermittently causing regulator to full field alternator. Batteries act like a capacitor and should keep voltages swings to a minimum.

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bad connection or bad ground at the vr.
I had a bad connector to the voltage reg that made it burn out a battery because it spiked so much.

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I'd start with checking the ground connections negative battery, body grounds, and clean battery posts as well. Voltage spiking to 18 volts seems like you are losing connection to battery intermittently causing regulator to full field alternator. Batteries act like a capacitor and should keep voltages swings to a minimum.

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Thanks for the great places to start, guys. These were the areas I was going to start at/around, but hearing it from others helps me focus. I'm pretty much electrically inept and can use all the help I can.

Another thing I probably should have mentioned is that ALL the wiring harnesses in my Challenger are original. And being the 4th owner leads me to believe that at least two of the previous owners have done some minor league hacking on the engine harness. Nothing terrible, but just old splices here and there, so I'm sure there's possibly a weak connection (or three) in there. Do you guys maybe think its time for a new engine wiring harness? And if so, where's a good place/vendor to get one from?

Dale

You may very well have more than one poor electrical connection. I agree that the voltage regulator connections are questionable--including the connections at the alternator (field wires--blue and green). Could also be a bad VR.
As far as the power outage--check the bulkhead connector--the ignition feed wire (blue I think) is located at the far end of the connector block, closest to the steering column. Make sure this connection is good--it WILL leave you stranded if not. You can take a male spade connecter and test for conductivity and some tension as you insert it, if its weak, you can take a fine nail or poker and carefully tweek the female portion on the firewall to increase the tension. If you don't mind altering your harness you can bypass the connection altogether (I am considering doing that)

Good stuff, Greg. I'll definitely also check the ignition feed wire at the bulkhead connector. This is just a fun car/ice cream getter anyway, so I have NO problem running bypass wires if it means superior reliability.

Dale

I would also check the fuseable link and it's connections!!!!!

Stock ammeter jumping or aftermarket volt gauge?

Either way, I had this problem in my '71 Swinger.
One night coming home it spiked and blew both my low beams!! Scary since it was after sundown. High beams took the full voltage and man were they bright.

Problem as it turns out was the voltage regulator. The bolts that held it to the firewall had been stripped, so after lots of vibration, they came loose and caused an intermittent ground.

So, in your situation, take out the regulator, clean the grounds and it's connector. Maybe throw on some dielectric grease to ensure a good ground.

Hi Dale, electrical probs are scary.. I had a buddy's buddy rebuild my alt to higher power, and now I burn thru voltage regulators. I bypassed my stock wiring harness by taking a heavy gauge wire from the alt to my starter relay. And disconnected the wire going to the rallye amp gauge. Now my volts goes to 18 after or near 3500 rpm. Scares the heck out of me. The fuel pump is screaming, but I can get it to go down to coast at idle.. Wonder whats wrong ? Never happened until the alt got "supercharged". I have an adjustable voltage regulator, but haven't installed it yet.. Love to see some answers , Dale.. My voltage reg. is burned up.. Everytime I replace, it burns up, but no damage , yet....

Dale, If your going to go with a new engine harness Try Bill and Rose Evans http://evanswiring.tripod.com/
Great people and a great product.