Long running electrical issue with my '65 Fury


Jul 8, 2015
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Monroe, CT
Hello! I've owned my '65 Fury for about 8 years, but have not driven it much, mainly due to a long standing electrical issue. Background: Factory 4 speed car, originally a 383, now has a nicely built '70 440. Rust free Arizona body, rock solid floor, frame, etc, stock suspension, steering, etc. The wiring appears to be original, in decent shape and un-hacked.

When I bought the car, it had the original and VERY tired 383. I found a recently rebuilt/running/still in the car 440 and the price was right. The engine had already been converted to electronic ignition, so I did the research and did the necessary work to convert my car to electronic ignition, ie. electronic regulator, ignition module, etc. I dropped the engine in and the car fired right up and ran really well.

I drove it a few times and started noticing that I was getting intermittent voltage spikes. After doing some more research, I bypassed the ammeter by soddering the wires together, cleaned the firewall bulkhead fittings as best I could, and installed a voltmeter. The car fired right up, but after driving it a few times, I was STILL getting voltage spikes, although less frequently. The voltmeter would peg for split second and then return to normal, about 14v or so. It burned out all of the interior light bulbs. I drove it a few weeks ago and nothing had changed.

I got tired of watching the car sit and get dusty, so this afternoon I dug into the bulkhead fitting again. This time, I removed every single male connector from the fitting and sanded them with 120grit until they were shiny. There are 2 main connections on the bulkhead, hot and ground, that are connected with a metal bus bar that goes through the fitting. The wires are connected to the bus bar in the engine compartment with screws, which were loose. I drilled and retapped the threaded holes, and used new screws so that they were now super tight. I buttoned everything back together and fired it up. I let it run for about 15 minutes, then drove it for about 20 minutes. No voltage spikes at all.

Question: Will dirty/bad connections through the bulkhead cause intermittent voltage spikes? If so, is that the only issue that can cause them, other than obviously damaged wiring? If not, what else could be the cause? Are there any other issues I should be aware of in re: voltage spikes?

I really want to get to the bottom of the cause because I'd like to have the AM radio converted to FM/satellite, but I DON'T want to fry a newly converted radio with another voltage spike, and I'm tired of replacing the interior bulbs.

I've attached pics of the bulkhead fitting on the firewall and the associated wiring, along with a pic of my alternator.

I welcome any comments/suggestions.






dirty connections are not going to cause a voltage spike...thats an alternator/ voltage regulator issue...looks like you have a later model squareback alternator in there and assume the later electronic regulator that goes with it?(never mind see it in the pics) maybe you got the wires crossed up? i'd temporarily run 2 new wires from the field terminals to the regulator, try another regulator etc...you dont still have one of the field terminals on the squareback grounded do you?...thats how the squareback would have to be hooked up with the original points style regulator
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I was recently plagued with the same thing. Fairly new alternator(powermaster roundback less than a year old), rewired whole car, upgraded lights to LED's throughout, etc but then had a pulsing issue with the headlights and dash back lighting. Replace the voltage regulator to the oe looking electronic one then upgraded to the newer dual phase setup with regulator. Rechecked all my wiring, connections, and relays but nothing seemed to fix the issue. Ultimately the less than 500 miles new alternator was bad(diode or something internally). Replaced with a 1 wire internally regulated alternator and completely removed the external regulator. Everything works great now. Someone on this forum recommended I check for excessive alternator A/C ripple which got me looking at the alternator as the possible issue even though I didn't expect that since it was new and didn't start until after the alternator was on for a bit. Just an idea
The wires are connected to the bus bar in the engine compartment with screws, which were loose.
Dirty connections might not cause a voltage spike, but loose ones can, causing the regulator to see spikes in system voltage, and telling the alternator to supply max voltage in response.

I have a 65 Fury 4-speed car also, although mine is a project car, sitting and waiting, sitting and waiting. Looks like yours might be pretty nice.

You should research the heat shield that goes over that rubber steering-shaft coupler, heat will cause that coupler to degrade more quickly.

Those chrome valve covers are the tall type. Non-chrome ones were used un the late 70s, and Direct Connection (remember them?) released them them in chrome - which looks like what you have. If you ever plan to swap to different VCs, I have heard the tall chrome ones are worth some money to the musclecar guys (for some reason).

How was the driverside motormount done? Looks like the bracket that is bolted into holes that were drilled/tapped into the oil pump? IIRC that's a Schumacher item? How easy was that to install?

Have you posted your car in the 4-speed thread?
My 70 Challenger was doing the voltage spikes many years ago. It sent the amp gauge to full charge for a short period then back to normal. I Knew it was in the regulation so swapped in another new regulator. Did the same thing. I finally figured out that my regulator was not properly grounded. I scuffed off some paint around one of the mounting screw holes. Added a star washer between the regulator and firewall and never saw any wavering of the gauge needle again. I suspect your issue may be the same. Now I always check for less than .05 ohms (not 5 ohms) between battery neg and my ECU, Alternator case, voltage regulator, and engine as they all need a good reference to ground.
Probably not the problem here, but one other thing to think about is something intermittent drawing a lot of current.

I had a drive where I noticed the meter jumping up for a short period every minute or two. Finally figured out that a power window switch was stuck. Window went all the way down, but the motor kept trying to run. Drew a bunch of current, the meter would shoot up until the breaker tripped. After a minute it would cool down and reset, starting the cycle all over again.

1. I see you're lugging your charge lead to the tensioning bolt on your battery terminal. That can cause you grief. Get a pair of MARINE battery terminals, with the lug studs separate from the tension bolts. These are MEANT to connect to lugged leads, which will simplify your connect/disconnect efforts, and improve the quality of your termination. I suspect the lug you currently have of causing your erratic charging behavior.

2. Is that #8 AWG wire you've run from the charging stud to the battery? How many amperes does that alternator push? #8 AWG is Ohh Kaaay for up to 100A IFF the distance you're running it over is SHORT! Running the charge loop[ in the original wire channel over the top of the intake, around the firewall, and then over the drivers side fender is LONG, TOO LONG for #8 over 75A. If you're just pushing 60A max, it will be FINE though.

3. Your beautiful work on the bulkhead connector duly appreciated, I would advise you to re-route the power lead from the starter relay through a grommeted hole in the firewall, avoiding the bulkhead connector. Cop cars were wired thus, to avoid trouble. You can put the fusible link at the battery, or the starter relay, using ring terminals.

4. All your lovely PAINT may be blocking good ground current to that solid state voltage regulator. Use a star washer behind the regulator and in front, after you abrade all that lovely paint and primer around the mounting studs down to shiny, conductive steel. Run a grounding bond jumper from the battery to one of the studs, using ring terminals and make sure this bond is included. Vibration can make for intermittent grounding of that voltage regulator, resulting in it pulsing the alternator field.

Attend especially to #s 1 and 4 above, and I expect your spike current blues will be gone for GOOD!