Big Thanks to the Help on my Last Problem and now....something new

[19bee70]

Alrighty, again I do appreciate the helping hands we get on this Forum. It's amazing! My last issue was the "leftover" bare post on my starter relay and it turned out after fabricating a ground wire from that post to the firewall....problem solved starts and stops with the key! I'm so thrilled! (after being apart for 20+yrs) However, that aside, my cluster was redone by Instrument Specialties and since I have nothing other than the factory "electronics" in the car I opted for an amp gauge refurb. The problem is when the car idles, cause that's all I can do right now, the amp gauge pegs off the dial to the right. With a multimeter on the battery, the amp reading jumps all over from zero to +70 amps and back down and all around. Nothing steady. What points for testing and what should I be looking at? Help

 

[dvw]

Make sure the regulator is grounded well. If it isn't, it will over charge. I'm assuming this is an original single feed wire (along with the thick bolt on battery feed) style alternator.
Doug

 

[twecomm]

Not sure how a multimeter "on" the battery would get you to an amp reading ? What type of multi meter do you have ? Is it a meter that clamps around the main battery lead to read DC amps ? 70 amps is wire melting territory for stock Mopar wiring. What is your DC battery voltage measure running and when not running ?

 

[19bee70]

Make sure the regulator is grounded well. If it isn't, it will over charge. I'm assuming this is an original single feed wire (along with the thick bolt on battery feed) style alternator.
Doug

Let me take a pic of the back of the alt and double check the ground. The reg is bolted to the stand off bracket so I have to check contact with the painted firewall.

 

[Geoff 2]

Make sure you have a ground strap from the engine to the body somewhere: f'wall, inner fender etc. Often left off after a resto.

 

[19bee70]

Make sure you have a ground strap from the engine to the body somewhere: f'wall, inner fender etc. Often left off after a resto.

Whoa....your right Geoff. I just looked and the only engine ground is the bat neg to the DS head. I need one for the rear PS head to firewall? I have seen those before.

 

[19bee70]

Make sure the regulator is grounded well. If it isn't, it will over charge. I'm assuming this is an original single feed wire (along with the thick bolt on battery feed) style alternator.
Doug

I have a pic here of the alt and I did double check the ground, metal to metal, surfaces. It sure looks good with no paint interference.

 

[Rebelrouser]

Alrighty, again I do appreciate the helping hands we get on this Forum. It's amazing! My last issue was the "leftover" bare post on my starter relay and it turned out after fabricating a ground wire from that post to the firewall....problem solved starts and stops with the key! I'm so thrilled! (after being apart for 20+yrs) However, that aside, my cluster was redone by Instrument Specialties and since I have nothing other than the factory "electronics" in the car I opted for an amp gauge refurb. The problem is when the car idles, cause that's all I can do right now, the amp gauge pegs off the dial to the right. With a multimeter on the battery, the amp reading jumps all over from zero to +70 amps and back down and all around. Nothing steady. What points for testing and what should I be looking at? Help

Not sure what kind of meter you have, but to read amps you have to run the voltage threw the meter. so, what I am saying is to read amps you would have to unhook the battery cable or big wire at the alternator and hook the meter in series. A 10 amp meter is the biggest I have ever had. So, if you would try it the fuse would blow immediately. If you have it just across the battery terminals, you can read voltage only not amps. I would first check the fuses in my meter.

I was an automotive instructor, and we had to buy tons of fuses for our meters, at least the first few weeks of shop class. Unless you have an inductive style meter that has a clamp that goes around the wire, which is what we used in the shop for checking cranking and charging amperage.

One easy check is to hook across the battery and put your meter in A/C volts you should read zero or very little, if you read any voltage the diodes in the alternator are defective. I would ask the local parts stores if they have a test stand to check your alternator before continuing the diagnosis. Not many of those old Mopar alternators would make 70 amps to my memory, 50 was about it, unless it had a police package.

 

[dvw]

That is a 2 wire alternator. I see the one wire has been spliced. One wire should be hot with the key on (factory blue wire). The other is normally green and feeds from the regulator. The regulator should be the flat style with the triangle shaped plug. If the ground at the battery and the regulator need to be close. What I mean is if the regulator ground is weak it will command the alternator to charge higher.
Doug

 

[19bee70]

That is a 2 wire alternator. I see the one wire has been spliced. One wire should be hot with the key on (factory blue wire). The other is normally green and feeds from the regulator. The regulator should be the flat style with the triangle shaped plug. If the ground at the battery and the regulator need to be close. What I mean is if the regulator ground is weak it will command the alternator to charge higher.
Doug

It sounds like you're saying...build a ground strap to run from the back of the block and maybe even ground on the same screw as the regulator, to have it as close as possible? It is the usual chrome, flat style with the triangle plug with 2 pins.

 

[dvw]

A ground to the battery would be the best. However these systems ran from the factory with the regulator just screwed to the firewall. So as long as it's bolted clean, tight, and the body has a good ground to the battery (usually right at the core support from the negative cable) it'll function. That leaves three posibilities. The green wire is pinched to ground. The regulator is bad. Or one of the brushes is grounded. Sometimes one brush is grounded so the newer style regulator will function with a one wire system. It would have to be the brush connected to the green wire, otherwise it would've smoked the blue wire by a direct short to ground.
Doug