alternator questions

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Dec 1, 2013 | 12:10 AM

#16

5-90

CF Veteran

Joined: May 2008

Posts: 3,018

Likes: 23

Year: 1988

Model: Cherokee

Engine: AMC242

Quote:

Originally Posted by BillyBoy

I've searched around for the answers, but came up empty. So I'll just come out and ask...

1.] Do cherokee 1998 alternators abruptly and irreversibly die? Or can they intermittantly and slowly die?

Yes, to both. Sorry, that's just the way it is.

Quote:

Originally Posted by BillyBoy

2.] The 4 wire harness on the back of the alternator, does it have a ground wire in it?

If you have four wires, then you should have an ancillary ground. It's the one screwed to the alternator case

Quote:

Originally Posted by BillyBoy

3.] Can a bad/dirty starter connection cause intermittant charging issues?

I suppose it's possible, but unlikely.

Quote:

Originally Posted by BillyBoy

I went up north with my friends this weekend, and my alt gauge dropped to 11-12ish. It would intermittantly go back up to the 14 {normal} usually after a re-start, and occasionally drop to nothing with the check gauges light on. Rarely will the power output increase without restarting it. Also, it likes to work better when warm.

I assume there must be wires and contacts to clean that might help. I've cleaned the usual grounds. I also took off the alternator 4-wire connection and cleaned it. Problem is, I dilithium greased it and was wondering if that's good or bad. The issue was present both before and after the cleaning.

Which wire from the alt does the electricity it makes go through, and to where?

Thanks for your help!

Not "dilithium" - just "lithium." And, lithium grease is a waterproof utility grease - not something you'd want to use on electrical connections (worse than WD-40!) Likewise, don't use dielectric grease - by definition, a dielectric is an insulator. You want to use something like electrical corrosion inhibitor (Gardner-Bender "Ox-Gard" is a good product) for something like that. You may have caused - in part, at least - the problem you're now trying to cure.

1) Clean all contacts thoroughly. Once the lithium grease has been visibly removed, clean again with electrical contact cleaner or brake parts cleaner (both will dissolve lithium grease. Neither will leave any sort of film.)

2) Inspect ring lugs, clean any that are still dirty with a small wire wheel or with sandpaper.

3) Inspect studs & nuts. Clean studs with a small wire wheel, replace nuts (the B+ stud nut is M6-1.0, the two field coil nuts are M4-0.7, I believe. No guess for the ground, but probably M6-1.0)

4) While you've got the B+ lead disconnected, perform a resistance test between the two ends. Replace if more than 1 ohm total resistance (it's contaminated or corroding.)

First thoughts there. Good luck!

Dec 4, 2013 | 08:50 AM

#17

sceaston

Newbie

Joined: Nov 2013

Posts: 2

Likes: 0

Model: Cherokee

Had Same Issue

My problem was the battery temp sensor mounted on the battery tray. You can test it with an ohm meter. It should read between 9k and 11k anything above or below its bad. They cost about $36.00 at the local parts store. You will get a strange look from the parts counter person, because 9.9999 of them will not know what you're talking about. So just tell them to look it up. Good Luck