69 Dart - overcharging issues

[JRapley]

I'll try and make this short and sweet.

Quick info: 1969 Dodge Dart, Car has single field alternator (round back) and mopar electronic ignition. (orange box, blue electronic voltage regulator)

Every now and then it started overcharging (bounced up to full C, 18V on volt gauge), I could rev the engine up quickly and it would correct itself.
Then it got worse and at any RPM above idle (1000+RPM) volt gauge would go to 18V, dash ammeter would peg to full C.

I had been having problems with the black charge wire at the bulkhead connector vibrating and causing NO charge issues. Someone`s previous wiring repairs to the terminals were less than desirable, so I ended up running a solid wire through the firewall to eliminate any issues there. (There had obviously been issues before someone else got to it too, due to the slightly melted plastic around the terminal in the bulkhead). Did that, unfortunately no change in over charging issue.

I then figured it was a faulty voltage regulator, so I replaced it (Electronic Mopar Performance one, PN:3690732). Scrapped the paint off around the mounting bolt and installed a ground wire from the mounting bolt directly to the battery -ive to ensure a good ground to the case of the regulator. Initially it looked like it solved the issue!

Multi-meter read battery at roughly 13V at idle, increased to 2000RPM and would get 14.6V at alternator & 14.3V at battery. Turn on loads, ammeter gauge would dip a bit then go back to where it was sitting before....

...but now there`s a new problem.

Went for a test drive, and the ammeter just started bouncing around like crazy! At idle it now sits at roughly 14.3V on my in car volt gauge, and revving up the engine causes my ammeter to dance around. It also, every now and then, jumping up to 18V and overcharging, but just for less than a second here and there when I rev the engine.

I just took the alternator off to go get it tested, just to rule it out as being the issue.

Looking for advice on where to start testing and looking next.

I`m really hoping it`s no wiring issues under the dash....

 

[67Dart273]

I always divide this into sections

Wiring problems in the charge wire (output)

Wiring problems in the field circuit


Problems with grounding

Alternator problems

VR problems

=====================================

It would be rare but "could happen" that a VR would cause troubles like this

Check:

At night or in the dark, look around different angles into the alternator. You may have to turn on the heater blower to load it. "Play" with the throttle. Look for odd sparking inside. Identify the brush sparking, they should be easily identifiable, and "steady."

But if you see odd sparking that comes and goes, it might be the stator has worn insulation off the windings, or even broken loose connections at the diodes, etc

Be absolutely CERTAIN the VR is grounded.

Try "rigging" a temporary wire that you can disconnect, so you can drive it this way for test. Run a solid wire from the starter relay battery stud to the IGN terminal of the VR, and run it long enough to see if it makes a difference.

See if you can "Rig" a voltmeter to the alternator output stud. If this voltage goes way high but the battery does not, this indicates a bad connection in the charge wire circuit.

 

[JRapley]

Thanks for the tips, i'll give them a shot tonight and see what kinda results i get

 

[roccodart440]

My 2 cents. Forget it all and get a 1 wire, 100 amp unit.

 

[67Dart273]

My 2 cents. Forget it all and get a 1 wire, 100 amp unit.

And for those that have an unmodified bulkhead / ammeter circuit this is a SURE way to just "finish off" the harness into a Great Big Melted Pile o' Goo

Further, the problem might BE the wiring in the first place.

"Throwing ****" at a problem is not the answer

 

[roccodart440]

My ampmeter is "linked". I guess I should have mentioned it.

 

[67Dart273]

My ampmeter is "linked". I guess I should have mentioned it.

I have no idea what that means. If you did not bypass the bulkhead, all the current goes "in and out" of the bulkhead, and the problem still exists. "Most of the time" the actual ammeter itself is not the problem

Even Ma "knew this." If you ever see how so called "fleet, taxi" optional wiring was done, it shows up dramatically (60-65a alternator)

 

[roccodart440]

Means my amp meter was disconnected and terminals linked together.

 

[Pete in NH]

Means my amp meter was disconnected and terminals linked together.

Okay, but that still sounds like the alternator output current is still flowing through the bulk head connector pins. As Del mentioned the ammeter can be issue but the bulk head pins and original gauge of wire used will always be a potential disaster waiting to happen with a big alternator. Just tying the ammeter connections together isn't enough.

To the original poster- The connector that plugs into the voltage regulator have been known to go bad and cause intermittent connections. Standard Motor Products and Dorman make replacement connectors with pigtail wires. Standard Motor-S573 and Dorman 85126.

 

[67Dart273]

To the original poster- The connector that plugs into the voltage regulator have been known to go bad and cause intermittent connections. Standard Motor Products and Dorman make replacement connectors with pigtail wires. Standard Motor-S573 and Dorman 85126.

That's great info but the Dorman no. is for the 70 / and later isolated field system.

 

[JRapley]

Well, I spent some time on it last night and looks like I have my issues solved (fingers crossed).

Got the alternator tested, passed without issues. Also took the brushes out and checked them, all look good with no issues with spring/movement.

I ended up spending some more time with the multi-meter and checking over wires. It looks like my issue came down to a slightly loose wire in the bulkhead (brown IGN wire), coupled with it also being slightly loose on the ignition switch itself. I also cleaned up the grounding point to the body from the battery.

I also switched out to another voltage regulator and REALLY cleaned up the grounding surfaces for it.

Note to any one chasing these types of electrical problems: you MAY think you have the grounding done well....but work at it and do it better. I could have sworn my grounding for the volt reg was good..turns out it wasn't. Go figure.

Also, on a side note. Previous owner installed a set of 3 aftermarket gauges under the dash. I had them unhooked during all this trouble shooting. Hooked them up and the ammeter seems to be a little bit more touchy now.
Is there any benefit to running an independant ground wire directly from the battery, through the firewall, to a terminal block to ground all my aftermarket accessories to INSTEAD of using a point on the dash/firewall. I'm assuming a direct ground connection to the battery for it can't hurt.

Thanks for the help and advice everyone, it's appreciated and I'm glad I got the issues solved.

 

[67Dart273]

Actually, grounding on these girls SHOULD be easy, because the unibody is "one big piece." The fenders, doors, hood, and trunk should not need any particular electrical attention (other than grounding the hood for radio static)

In other words a couple of nice big oversized bonding straps from the engine to the body, and a really good nice big battery ground cable "should do it."

The VR and Mopar ECU are a (continuing) problem for many. NO electrical device should ever be designed as these are, grounded "through the case." MUCH better to have a dedicated ground wire, which can be secured to a nice BOLT.

Of course in the case of the VR, Ma is not unique.

 

[Pete in NH]

That's great info but the Dorman no. is for the 70 / and later isolated field system.

You're right! I saw the 3690732 number and thought it was the electronic flat pack regulator instead of the blue constant voltage one. Anyway, converting the 69's and earlier systems over to the dual field terminal electronic systems, I think is a worthwhile upgrade. It seems to be getting harder to find decent quality parts for the earlier system.