Smoking voltage regulator

Hello everyone. I just connected the battery on my freshly built 72 Mach 1. I connected the battery and turned the key to the "ON" position to check the voltage is going to the right places. Right away I smelled that something was hot. I found smoke coming out of the back of the new voltage regulator. I disconnected the battery and removed the voltage regulator. Nothing appears to be burned. Everything is new and the car hasn't been started yet. What could be causing this?

Forgot to add, I disconnected the positive cable from the solenoid after I saw the smoke. That's why is not connected in the picture.

Did some research online and it brought up a question about a possible cause. Would not having an engine to chassis ground strap cause this?

First, never disconnect the positive battery cable, but instead disconnect the negative. If you inadvertently hit your wrench against a fender while removing the + cable, you will end up welding.

Could be the missing ground...but it sounds like there's a dead short somewhere. Here's my list of checks prior to connecting the battery for finding shorts:

Physically install the underdash harness with fuses. Connect all underhood and taillight harnesses.

When ready to check out the harness, close all doors, turn off all lights, ignition key in the OFF position, accessories off, etc. Make sure both battery connectors are disconnected. Connect the positive battery cable to the starter solenoid. Leave the negative terminal disconnected from the battery. Then use a digital volt meter to measure the current draw across the battery. Place one probe of the DVM on the negative battery cable terminal, and the other probe on the negative battery post. Be sure that the DVM is set to amps, DC. If there are no shorts in the wiring connections, the reading should be on the order of 30 milliamps or less. Anything above 1 amp indicates some accessory is on; readings above 10 amps (may blow the fuse on the DVM) indicates a dead short.

If you have a short, disconnect all other wiring from the starter solenoid post where the battery connects and re-measure the current. If current drops, the source is the underdash wiring harness or the harness from the starter solenoid to the firewall. Reconnect the wiring to the starter post and then disconnect the underhood harness from the firewall and test again to isolate the source of the short.

If the short is not in the underhood or underdash harness, the problem lies in the alternator or voltage regulator. Disconnect each of these in turn to isolate the source.

If the short or high current comes from the underdash region, keep the battery negative side disconnected and remove one fuse at a time. Measure the current as above. If you now see low current, there is either a short or an item on that particular fuse circuit is on. Turn off that item and continue checking.

Eventually, you’ll have low current readings with all fuses installed and all wiring connected. This series of tests checks all of the battery directly powered systems. To check the Accessory systems, now repeat all of the tests above with the ignition key in the ACC position. The current with the key in the ACC position may be up to 1 amp or so. When all of the tests are done and no anomalous current is noted, at that time, and only at that time, is it safe to connect the negative battery cable to the battery.

Thank you very much for the time you took to post the information. By the way, as you suggested, I removed the positive cable after I disconnected the negative. Many years ago I saw what happens when you don't when someone I knew made that mistake. The reason I removed it completely because it was getting in the way. I will get on these checks and let you know the results. Thanks again

I did as you suggested and found I have a 1.4 miliamp draw with the ignition off. With the ignition on I have a 20.2 draw but it fluctuates within 0.5 miliamps. It's a little doesn't then what you specified I believe. With the ignition off is 1.4 miliamps instead around 30. With the ignition on it is closer to 30. I will not tinker with it until I hear from you so I don't do something dumb.

Do I have the multimeter on the right settings? I looked online for the correct miliamp symbol and found that. It makes more sense to use the mA though. As you can tell I rarely do electrical work.

This is stressing me out because my wife is divorcing me and I am supposed to move out of my house (and garage) in two weeks. I have finished completely rebuilding it mechanically. I installed brand new brakes, suspension, steering, trutrac 31 spline differential with matching axles, rear disc conversion, wheels, tires, tko 600, hd driveshaft, engine professionally built and many brand new small parts. I still have to paint the car and I'm trying to finish in time so I can drive it away. This car has been mine for 16 years and I neglected it for too long. It sat for over ten years and I am trying to make it what it deserves to be but my situation ia a little more complicated now. Just needed to vent.

You have it on the micro-amp setting, so your key on and off draws are very low. You normally use the middle position to measure milliamps and the bottom setting to read full amps. When you use the full amp setting you have to move the red test lead to the connection on the left.

Thanks! Here are the readings with the correct settings if I'm reading it correctly, I'm only drawing 2 mA in the ON position and almost nothing in the OFF.

I agree, this indicates you have no shorts, and I'm guessing the points are open so the coil isn't adding any load.

There's a couple of wire-wound resistors on the back of the regulator. It's possible one of them had some oil or grease on it that burned off, or one of them burned up.

one more thing to rule out do not use those reproduction voltage regulators they are garbage.

get a solid state regulator to rule out the junk reproduction one... later when all the problems are gone over and the car is working, you can pull the blue cover off the reproduction regulator and stick it on the modern solid state regulator for the looks.

i went through 5 or 6 of those reproduction junk heaps.

Those readings look good, although I had to zoom in on your DVM to make sure you hooked it up correctly.

I don't know what happened the first time, but you're ready to try it again, if you want, before getting a new VR.

I can't thank everyone enough, truly. I'm glad I don't have to rip the wiring or interior apart. I'm starting to think the smoke was from something burning off. There was no smoke the last time I switch the ignition on, but I want to be cautious before moving on. I should be installing a ground strap tomorrow. Also, when I started working on the car again, I noticed the screw holes in the apron that attach the voltage regulator enlarged to where I couldn't use the screws. I drilled the holes and installed rivnuts. If the rivnuts don't have good contact to ground, could it cause the smoke? Regardless, I'm still going to remove them and clean up the contact area and install new rivnuts just to make sure of good contact.

One more thing, the regulator says it's made in America which makes me think it's a genuine motorcraft. Has anyone had a bad experience with these? Are they really motorcraft or good counterfeits? How cam I tell the difference? Once again, thank you everyone

One more thing, the regulator says it's made in America which makes me think it's a genuine motorcraft. Has anyone had a bad experience with these? Are they really motorcraft or good counterfeits? How cam I tell the difference? Once again, thank you everyone

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Yes, they are garbage.

they are reproduced by somebody that bought the rights to put a license on the decal for lid that is all. they are complete junk.

the modern replacement ford service part is a solid state regulator.

the original regulators are mechanical with a kind of points.

watch video

I appreciate the info. Good to know I have a quality D2 solenoid. I'll be hunting down a another voltage regulator tomorrow.

The important question, what brand and model voltage regulator should I get?

pretty much anything solid state is good i grabbed one from Advanced auto about 2 months ago.

i had the reproduction regulator for 9 years. i went through them like candy, the last one managed to last about 5 years, but i had a feeling it was going again as my lights started to flicker. i checked it with the volt meter and it was spiking over 15 volts. at that point i said i'm done with them. there are also numerous videos talking about these regulators and problems with them. due to the mechanical nature they also change regulation with engine heat and ambient temps.

if you want to drive the car then avoid concourse parts most of them are junk.

I took a trip to Napa and picked up an electronic voltage regulator and so far it appears things are as they should be. Of course the ultimate test is whether the car will operate the way it should. Another positive about the electronic regulator is that I like how it looks better than the "Motorcrap" brand.

I cannot thank everyone enough for their help and suggestions. Hopefully tomorrow she roars to life again and soon we can hit the road again after so long.

To midlife, on behalf of myself and every person your post will help in the future, thank you so very much for taking the time to write such a thorough explanation. I am in your debt.