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Discussion Starter · #1 ·
I'm thinking voltage regulator, but not sure.

Here's what I've got.

later alternator, electronic VR mounted on the inner fender, just behind the radiator support on the passenger side, #8 going to the 750 CCA battery in the trunk on the pass side (actually to the battery side of the disconnect), #2 going up the driver's side to a terminal where the starter cable taps, and a wire to the solenoid on the inner fender.

when driving, the lights randomly dim really low and brighten really bright, even at a steady rpm. does it at idle, and moving.


also, possibly related, doesn't want to start when hot. even with timing backed off from 18 initial to 12 initial, there's no difference (actually seems like it may be harder to turn over with it backed off).
have ceramic TTIs with inner coating, small starter, and starter heat shield.

spins fast when cold. oh, and it's a low CR 400.
 

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Make sure you have your engine block grounded good to the firewall area and run a heavy (I used 6 Ga) 2-6 ga wire to the battery negative from the block. Bad grounds WILL cause goofy troubles. Your body is NOT a good ground, It is one big resistor.

Herb
 
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Discussion Starter · #4 ·
I have a motor plate, so the engine should be grounded well to the chassis. I made sure to have clean areas where all the plate bolts are to get good metal-to-metal. maybe I do need a cable to the trunk from the front for ground. never saw a car with one though.
 

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Sounds like you should check the voltage with the car running and lights, blower motor ect on.
f it is not around 13.5 you could have an issue with the charging system and you are running off the battery.
 
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Discussion Starter · #8 ·
how about this????

I put the regulator on the inner fender, passenger side, near the front.
I was reading about the sensing point of regulators and think I may have an idea. I placed it here to minimize the amount of wire i'd have to run. However, this puts the voltage sensing point near the alternator, so it's regulating the alternator, which feeds to the battery in the trunk, and them up the #2 cable to the front again, at the distribution block. I'm figuring that maybe this is giving me a huge voltage drop by the time it goes the length of the car 2 times. the fix would be to go ahead and run the necessary wire to power the regulator from the block at the front, and NOT near the alternator output.

I attached some temporary cables in numerous configurations, and the only thing I ever got was fast starter action when I grounded directly from the engine block to the battery in the trunk. So the hot start "problem" should be a simple fix too. more #2 for the ground.
 

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Here is my thought, sounds like the field circuit going open circuit and then back to normal (12 to 14.5V) or something else is intermitent. There are many potential problem spots. Here is what I would do:
1) By some new brushes for the alternator.
2) Polish the copper slip rings on the alternator rotor (the brush contact surface).
3) Inspect the solder connections from the rotor winding wires where they connect to the slip rings.
4) Inspect the stator wires where they are connected to the diode block and the diode block where it is bolted to the alternator frame.
5) Follow the hot wire from the regulator back to the firewall and inspect that connection on the old factory plug. This also could be tapped off of the ignition, possibly you have no power to your ignition, hence the starting problems.
6) Try a differnet voltage regulator, maybe yours is bad.
7) You could also have bad diodes in your alternator.

Maybe you can drive with a digital voltmeter and watch the voltage, see what the highs and lows are. That might help to figure out whats going on.
 
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