[ken66]

The patient is a 66 Bonneville, automatic trans, HEI conversion w/relay, new Napa 55a alternator (RAY 134004), new Wells VR716, new battery with 1/0 cable. The symptoms:

1. 12.6v over the battery with the engine off, 14.3v at hot idle in park (800 rpm or so) with lights off, 14.6v at idle with lights on. Idle readings are not rock steady but fluctuate, plus or minus a tenth of a volt.

2. Any lights that are on will flicker and ammeter goes wild at higher rpms. Specifically, at hot idle in park, ammeter seems to rock on the C side of things with a steady rhythm and lights flicker. As you raise the rpm, the ammeter looses its rhythm and vibrates wildly whether the lights are on or not - lights flicker.

3. In drive, foot on the brake, 650 rpms or so, the ammeter is rock steady, straight up, and the flickering goes away. When you get on the gas, the ammeter starts to wiggle again and the flickering returns.

4. Other than that, it seems to start and run fine.

I have read that the VR needs to be well grounded to the firewall. I have star washers under each of the 3 screws between the VR and the firewall and I added a new ground strap between one of the VR screws and the back of the driver's side head. The other ground straps are original but appear to be in pretty good shape: driver's head to firewall, driver's head to frame, passenger's head to frame. Only other (probably irrelevant) detail I can think of is that the horn relay is disconnected.

Can anyone help me figure out what is causing this? Other than being annoying, could it be causing any damage? Any advice you could offer would be great. Thanks in advance.

[LASJayhawk]

Almost sounds like the new alternator or regulator is bad...........

What is the voltage doing when the needle is jumping around?

My best guess:
Assuming 66 is wired like a 65 make sure the alternator/car/battery connection is good clean and tight on the back of the starter solenoid.

[george kujanski]

The flickering is usually caused by the regulator responding too slowly to the electrical load changes, described as oscillation. It may be caused by poor ground connections or a poor connection to the regulator from the ignition switch. The ignition switch is supposed to feed battery voltage to the regulator to sense ignition circuit voltage.

Ignition circuit voltage is supposed to be essentially battery voltage, but in an old harness, there may be poor connections thru the fusible link, etc where a voltage drop exists in the system, and changes with loading. This would then cause poor regulation, resulting in a voltage oscillation.

Another possible cause is that the resistors on the bottom of the regulator are corroded and have a poor connection.

As a test, with the engine running and lights flickering, attach a jumper wire from the battery positive to the regulator term that is NOT the blue wire. It'll probably be a brown wire. If there is a poor connection in the battery positive-to-ignition switch circuit, this should cause the flicker to stop and the reg to regulate correctly.

george

[ken66]

Thanks so much for the thoughtful replies. I'll check the connection to the starter (it has an aftermarket mini-starter) and try to perform the test George suggested (don't jump the blue "f" wire but rather the other wire to the VR). I'll report back soon...

[ken66]

I had the chance to execute the test George suggested. I set up a jumper from the #3 terminal of the VR (it sees the black w white stripe wire) to the positive post of the battery. The lights were steady upon starting the car and the ammeter was also steady, pointing just to the right from center, toward c.

So. That suggests a poor connection in the battery positive-to-ignition switch circuit. Any thoughts on where in that circuit problems are most likely to occur?

Thanks again for your help. I feel like I'm on the path to sorting this out.

[mechanic17]

Dunno a damn thing about electricity or wiring, but I did discover my flickering electrics were due to the harness under the steering column, and have heard a few others with same-same. The solution was to tie-wrap it up tight so the movement was eliminated.

Discovered this by running the car and reaching up and shaking stuff under the dash one at a time.

[LASJayhawk]

The connector on the starter, listed earlier
the connector from the engine harness to the fuse block assy (under hood)
Ignition switch connector

[ken66]

UPDATE: First, thanks all for your help so far. I dropped the starter (for the 90th time) and reworked the connections. I pulled and examined the engine harness connector - looked ok. I checked the ignition switch connector and it didn't appear to be damaged in any way.

Still, the flickering continues. While I can't determine what is causing the flickering, I have determined that I ALSO have a battery drain. Could the flickering and drain be connected in some way? I believe that the drain is in the ignition circuit and here's why.

As I mentioned, I found that if I jumped the black wht stripe wire from the regulator to battery positive, the flickering vanishes and the ammeter stops jiggling around. I found also that the battery will drain overnight if connected. If I put a test light between the negative battery post and negative cable (cable disconnected), it lights. I can get the light to go out completely by pulling only the wire from the "F" terminal of the alternator. Does that mean anything?

Does anyone have any ideas about where to turn next? Any help would be greatly appreciated. Thanks!

Ken