Dodge RamCharger Central banner
Status
Not open for further replies.
1 - 2 of 2 Posts

·
Registered
1987 12-Valve Cummins on tons and 37's.
Joined
·
48 Posts
Discussion Starter · #1 ·
So I'm in the final stages of my 87RC Cummins build. It runs good, drives good but I cannot, for the very life of me, get the blasted alternator to charge!

It's dead! Kaput! Zero charge. Nothing. Nada. Zip!

I started with a new 120A nippondenso alternator, new voltage regulator, new field wires, new field wire/vr connector, and I'm using the original switched 12v coil wire for the reference/excitor source (verified "hot" with the key on).

I ran the green field wire to the "bottom" field post on the alternator, the blue field wire AND the switched12v to the "top" post.

I started with the voltage regulator that was present (and working) with the original 318 located on the firewall. When no charge was observed, I replaced the old VR with a new one. Nothing. So I moved it to the brand new passenger-side fender, after removing the fender paint. Still nothing.
I then switched the field wires. Nothing. Moved the switched 12V reference wire to the other field wire. Nope!

At this point, I suspected a bad ground... even though the alternator is grounded to the engine by both the brackets and a dedicated ground strap from the back of the alternator housing to the front of the cylinder head. The engine itself is grounded to the chassis, along with a 1/0 cable directly from the block to the frame, which connects to the negative battery terminal along with a body ground wire to the core support. All ground connections were polished to a shine with an 80-grit flap disc.

I even ran a separate ground wire directly from the neg. battery post to the VR. Still nothing...

And by nothing, that is going by the new digital volt gauge I installed, along with my multimeter (both read 11.8V with the engine running.
With the charge wire disconnected , zero Volts are read at the charge stud of the alternator.

I took the new alternator off and took it in for testing. It tested "good" with me standing right there observing

So now I'm stumped. What the hell am I missing here?
 

·
Super Moderator
Joined
·
14,325 Posts
one thread per problem only please. Locking this one
 
1 - 2 of 2 Posts
Status
Not open for further replies.
Top