Daniel Paisley wrote:
>
>
> Re: Charging/Alternator ?
>
> Group: rec.autos.makers.jeep+****** Date: Sun, Dec 12, 2004, 10:25am
> From: romainm@sympatico.ca (Mike Romain)
> You are describing a dirty battery cable.
> I would be checking the ground side first, the cable goes to the engine
> block and gets corroded there, then the next cable is a wire mesh one
> that goes from the rear of the engine head to the firewall, this one is
> most likely the bad one, but...
> I also have seen the alternator bracket itself lose the ground. You can
> check this by using a booster cable from the battery negative to the
> alternator case. If the volts stabilize you have found it.
> The other one that will cause those symptoms is a dirty connection on
> the starter solenoid on the firewall. The alternator wire and positive
> battery cable connect there and get dirty really easy.
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88
> Cherokee 235 BFG AT's
> ___________________________________________
> Mike, I checked the negative ground on the block before I posted, my bad
> for not saying so. I never thought about checking the mesh wire going to
> the firewall. I did find corrosion on the electrical plug that goes to
> the alternator and sprayed it with some CRC electronic cleaner. Now
> then, if the alternator bracket itself has lost 'it's' ground, how does
> one help it 'find' it's ground again?
> TIA, Dan

The easiest way is to cable the thing. You can get battery cables with
2 loop ends and go from a bolt on the bracket to the bolt on the block
where the battery cable hooks up. Taking off the bracket to clean it is
a real pain.

Which plug are you talking about that you found the corrosion?

You have what is called a 'one wire' GM alternator on there. It has the
plastic plug with two wires in it and the red wire jumpered from there
to the alternator power post right?

The small wire, usually brown, sometimes yellow is the trigger wire.
This comes from the coil power wire and is tied in on the 12 volt side
of the ballast resistor wire up near the brake booster in the harness.

If this is the 'dirty' wire, then your alternator might not be getting
the excite signal right away so it waits until high rpm (or heat helps
the connection) to turn itself on. This is how the 'one wire' feature
works.

And don't forget the battery cable to the solenoid relay on the
firewall. That is a sneaky spot for a dirty connection.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's