Electrical Problem

[cudabob496]

I'm out crusing today, and all of a sudden the alternator amps output is up around 30, normally around 10,
and voltage is cycling above and below 16 Volts. Amps and volts kept cycling from normal to these high values.
I assume bad voltage regulator? Is there a particular voltage regulator I should buy?

[edl94]

First check and make sure the voltage regulator is grounded well to the firewall. Also test the battery, a shorted or dead cell will make it charge like that. Or the regulators are cheap any auto parts store can fix you up.

[cudabob496]

thanks, I noticed Summit has a restoration VR for Mopars, and a Race Only VR for Mopars.

P3690731

[roadman5312]

            So is the factory amp gauge still hooked up?  Not bypassed ?  And an aftermarket voltmeter I'm assuming ? 

[TelisSE440]

            So is the factory amp gauge still hooked up?  Not bypassed ?  And an aftermarket voltmeter I'm assuming ?

I was wondering the same thing, how did you do your electrical setup?

[cudabob496]

I was wondering the same thing, how did you do your electrical setup?

I have a heavy gauge wire going from the alternator, through an aftermarket amp gauge, to the
positive on the starter relay.  Then I have an aftermarket volt meter. So I can pretty much
see what current the entire engine is drawing. Normally max is around 10 amps, or 20 if I
turn on my electric fan.So, basically I've done the bulkhead bypass mod.
I saw the current get up to 60 amps a few times, when driving today, so I was expecting fuses to blow,
or a fire to start! The fuse on the wire from the alternator is 40 amp. Fortunately, I have a cutout swith
from the battery in the trunk, bolted to the panel that contains the tail lights. One time I did have wires melting
and that cutout saved my bacon.

Actually, I should not have taken the car out today, as at startup, I notice right away that the amp gauge was
up around 30, instead of 10. Guess I was hoping the situation would go away, but it only got worse. I've got
12 diff aftermarket gauges in my car, so its a lot more easy to see when a problem is arising.

why can't MP build a better VR. This one lasted about 10,000 miles. Maybe the MSD puts more
of a strain on it?

[734406pk]

I'm out crusing today, and all of a sudden the alternator amps output is up around 30, normally around 10,
and voltage is cycling above and below 16 Volts. Amps and volts kept cycling from normal to these high values.
I assume bad voltage regulator? Is there a particular voltage regulator I should buy?

Another area to check is the blue wire (switched ignition positive) that goes to the VR. The VR uses this voltage for sensing alternator output voltage. So if you have a voltage drop to the VR sense wire the alternator output voltage will increase until the VR senses about 14 volts. This could explain your intermittent high voltage and amperage readings as well. The VR may be ok and it's just trying to do its job maintaining about 14 volts. Check your connections in the engine harness. There is several splices in the ignition circuit to check. If you have a handheld volt meter it would be very helpful in diagnosis.

[cudabob496]

Another area to check is the blue wire (switched ignition positive) that goes to the VR. The VR uses this voltage for sensing alternator output voltage. So if you have a voltage drop to the VR sense wire the alternator output voltage will increase until the VR senses about 14 volts. This could explain your intermittent high voltage and amperage readings as well. The VR may be ok and it's just trying to do its job maintaining about 14 volts. Check your connections in the engine harness. There is several splices in the ignition circuit to check. If you have a handheld volt meter it would be very helpful in diagnosis.

thanks, will check out the wires!

[HP_Cuda]

Everything you said is happening has happened to me because the VR was not grounded properly to the firewall.

It was freaky to see the amp guage (now disabled) slammed to the right and I felt the wiring harness and it was getting pretty warm.

Swapped out for a new VR and made sure it was grounded good and no more problems!!!

[cudabob496]

Pretty stupid that we have a VR, that does not last very long (in my experience) and when it fails,
it fails in a manner that might melt your electrical system, or start a fire.  My ammeter was pegging
past 60 amps, and voltage was slammed all the way to the right (16+) as well. For heavens sake,
its 2015! We put a man on the moon in 1969! Seems it would be a simple design to make a better
VR!

[TelisSE440]

Pretty stupid that we have a VR, that does not last very long (in my experience) and when it fails,
it fails in a manner that might melt your electrical system, or start a fire.  My ammeter was pegging
past 60 amps, and voltage was slammed all the way to the right (16+) as well. For heavens sake,
its 2015! We put a man on the moon in 1969! Seems it would be a simple design to make a better
VR!

  100%

[734406pk]

Pretty stupid that we have a VR, that does not last very long (in my experience) and when it fails,
it fails in a manner that might melt your electrical system, or start a fire.  My ammeter was pegging
past 60 amps, and voltage was slammed all the way to the right (16+) as well. For heavens sake,
its 2015! We put a man on the moon in 1969! Seems it would be a simple design to make a better
VR!

There are other VR's available that will work but they won't look OEM.

[TelisSE440]

When mine broke, I found an original looking VR for 15 $. I bought two of them with the one installed last year, with no problem at all. While the other is in the tool box inside the trunk for emergency...

[roadman5312]

Don't rely on grounding the vr with the sheet metal mounting bolt. Make up a ground wire to the motor       Everything on our build has it's own ground wire to battery or block.

[734406pk]

Don't rely on grounding the vr with the sheet metal mounting bolt. Make up a ground wire to the motor       Everything on our build has it's own ground wire to battery or block.

That's how it should have been done from the factory!  Ground faults on the Mopar regulator are a common problem. Nice job Mark!