Ignition issue, paging Del

@67Dart273 your presence is requested.

I was driving the Dart to work today and I was going up a long grade doing about 60 and I noticed that the Ammeter was showing a slight discharge condition. When I got to the top of the hill and lifted suddenly it shot back over to the charge side of center. I was really close to work so I didn't get a chance to really play with it much but I came to the finding that when I give it at least half throttle or more the gauge dips into discharge. When I got to work and popped the hood, nothing seemed out of order.

On the way home it started doing it again, but it took roughly 8 minutes of driving to start and this time it got progressively worse just as i was arriving home (13 minute drive) I took this video.



At the start of the video when the needle is jumping around, I was gently accelerating up a slight grade from a stop. If you turn the sound up, you can hear me getting in and out to the throttle twice near the end. What you can't hear is the engine misfiring during the discharge condition which was a new symptom.

Anyone know where to start troubleshooting? Del?

First thing I'd do is check the belt, second thing is check brushes.

If neither, then "try to get it to act up" (We ALL hate intermittents LOL) while monitoring one of the other field connections. The blue wire field should always have 12V in "run" and the green will vary, but should be "low" when charging. That wire acts as a ground controlled by the VR. Other than that check the ground on VR, and work the VR plug in/ out several times in case it's corroded.

Put a volt meter on for your next drive. If voltage goes down as it goes into discharge you are loosing charging someway.

Electric or mechanical fans?
What type of ignition system do you have?

Does it do this when in neutral in the driveway?

Personally I would have the charging system checked at the local auto parts store.

67Dart273 said:

First thing I'd do is check the belt, second thing is check brushes.

If neither, then "try to get it to act up" (We ALL hate intermittents LOL) while monitoring one of the other field connections. The blue wire field should always have 12V in "run" and the green will vary, but should be "low" when charging. That wire acts as a ground controlled by the VR. Other than that check the ground on VR, and work the VR plug in/ out several times in case it's corroded.

Click to expand...

so it sounds like you're leaning towards charging system problems? I was too until it began to misfire and then I wondered if the ecu may be dying.

If it ever stops raining here I'll get out and do some checking.

Dana67Dart said:

Put a volt meter on for your next drive. If voltage goes down as it goes into discharge you are loosing charging someway.

Electric or mechanical fans?
What type of ignition system do you have?

Does it do this when in neutral in the driveway?

Personally I would have the charging system checked at the local auto parts store.

Click to expand...

the only loads on the car is the wipers, headlights, blower motor for HVAC and the '73+ chrysler electronic ignition module. It does do it in park and neutral but oddly it doesn't seem to do it when the engine is cold. If I dont find anything obvious I'll probably have the charging system checked.

Because it does it in the driveway much easier to trouble shoot. Only when hot suggests issue with voltage regulator or alt.

Misfiring could be voltage dropping really low during discharge condition.

Has there been any evidence of the ammeter intermittently bouncing? That could indicate problems in the ammeter/ connections, bulkhead connector, or "cough gag" the welded splice

First bad one of those I found in the Navy, in a friend's 68 RR in about 71-72. His ammeter was going nuts. Soon, we had the cluster torn out and the harness all over the front seat, and he was beginning to wonder if I knew what I was doing. So was I. Bad welded splice, and I've seen or heard/ known about roughly a dozen over all these years.

That is rare, but certainly can happen

Could be engine to chassis ground connection, since related to throttle operation, and interferes with ignition and charging.

Might also be IGN connection in bulkhead connector, poor connection there interferes with ignition and charging. Gas pedal operation on /6 might flex fire wall near bulkhead connector.

Yes. Check the accesible connections first visually. Start with the battery feed and alternator feed lines to the bulkhead. Alternator output stud (marked BATT) on the case should not be loose, nor any connection.
If the ammeter is only showing charge at higher revs, then the battery takes over at lower revs (discharge) could be a bad diode or one of the windings failed so the output at any given rpm is decreased.