This is one for the people who love finding out electrical problems, I'm not one of them.

So, got the head on my 200 (off of a 79 Granada) and got the engine running TOP. After a day of enjoying my new motor, I got home, then tried to start it the next day. It turned over very slow, but being that I had to get to work I drove it there then drove it home. At that point it was turning over VERY slow, which made me think that my alternator was not charging my battery.

So I replaced the Alternator, hooking up the ground, battery, and field terminals as they should be. After starting the fully charged 12.6 battery, my multimeter showed only 12.3 volts going to the battery while the motor was running. Shut it off, start it again, down to 12.1 volts, and so on.

Went back to the parts store and tested the new and the old alternator -- both were good. Returned the new alternator and bought a voltage regulator. Went home, put it on, still only 12.3 volts and dropping. You can take the negative cable off the battery and it will die immediately.

Not the alternator, not the voltage regulator, 12.3 volts to the battery terminal on the alternator, and I jumped a ground wire to see if it didn't have good ground. Test with the multimeter showed continuity and voltage in my wires from the alternator to the voltage regulator. What's left?

And just when I thought it couldn't get any worse, I turned on my headlights to see what kind of drain they put on the battery. When I turned on my headlights, the left indicator lamp on the dash lit up, and when you hit the turnsignal, the headlight flashes with it! The front left headlight is also extremely dim now. I don't know if my two problems are related, or just a coincidence that my electrical system decided to give me a giant headache today!

Any help on either problem would be greatly appreciated!

 

Did you reinstall the heavy gauge engine-to-body ground cable?




.

 

Where is this cable located? I found a loose wire that looks as if it is grounded to the firewall by the master cylinder but I can't find where it hooks up.

 

It's been years since I had a 6 cyl in my car, I forget exactly where it attaches.

But it's not that important where you locate the ground. Keep it away from the exhaust, try to make it inconspicuous.
Just put a cable (8 ga. minimum) on any bolt on the block and a bolt on the body (strut tower, motor mount, etc.)

Most of the time this cures the electrical problems you're describing.

 

Tried running a wire from a bolt on the fender to a head bolt, didn't help any. Thanks for the response though. Maybe it's time to let someone who knows a bit more take a look.. This is driving me crazy.

 

The problem was the connection on the voltage regulator. It wasn't letting the wires make connection to the regulator! That didn't solve my headlight turnsignal problem though. Any ideas there?

 

The easiest way to isolate electrical issues is to isolate 1/2 at a time. so there is a harness disconnect just outboard of the MC in the left firewall area. take the plug apart and look for any signs of arc-over or anything else that looks wrong. If all looks OK, you can pull the bulbs out of the turns & disconnect the headlights then "ohm" the headlight feeds and the turn signal wires to each other - there should be no continuity.
If that's all OK you need to go to the interior of the car and pull the headlight switch plug and the turn signal switch plugs off. Again "ohm" for connections there should not be any. If there are continuity issues, you will need to isolate where in the harness that is or just replace the harness ($$$$). You can download a wiring diagram form several sources here on the "I-net".

 

Interesting discussion. If I can be forgiven for "piggy-backing" onto this thread...been having similar problems myself, but with a 289 converted to Duraspark ignition. In my case though, windshield wipers work "fairly well" with ignition in accesory position, but with engine running they barely creep across the glass. Plus, have tried every type of connection, but the Autometer tach will only read 1/2 actual rpm (and yes, cylinder switches are set correct). Then, the other day, the brake/turn signals stopped working, but tail lights are ok. Checked for blown fuses...all fine. And yes...engine has a thick copper ground strap connected from the right-side head to a firewall screw.

 

This really sounds like a ground issue. I'll try to make it easy but, when you're working with electrical, it's easy to get turned around into circles. First, check all of your lights, make sure they work. The headlights and turn signals share a ground. If you have a bulb burned out, it could be looking for another place to ground. Second, have you replaced your neg battery cable? Does it have a small wire that grounds to the body? (best if it does) Third, I'm not sure about the 66 but, the ground for the lights may be near the regulator...make sure of good connection.

Have you ever seen the older chevy trucks that have the front marker lights come on when they step on the brakes? bad ground.

 

I agree that it sounds like a ground problem.