Charging problem 90 XJ

My XJ died due to a no charge condition, battery tested good, alt tested bad. Replaced alt, ammeter showed no charge so I checked the fuse links and connections at the.....well I'm not sure what it's called but it has a stud that all the fuse links bolt to and 4 spade type connectors, I didn't really do anything to it other than plug and unplug and clean the connections.After that it started charging showing

14 amps. Well it's not charging again, I went thru the same motions to no avail. Any ideas?
Reply to
JRK58
Loading thread data ...

I should add that I charged the battery overnight prior to installing the new alt. I have checked and cleaned both ends of both battery cables. The fusible link shows no sign of over heating, and it charged fine for 3 weeks prior to this problem.

Reply to
JRK58

I have seen several loose their ground between the alternator bracket and the engine block so you might want to try a booster cable from the battery negative to the alternator case to see if it fires up.

If not, try from the batter negative to the firewall, lots of times that wire mesh ground strap from the head to the firewall rots or breaks.

And that place where all the wires are is called the starter relay. The bolt post on it is just a convenient connection to bring a mess of wires together.

Also those fuse links can just up and die with no visible evidence. They get hard and crystal, then a flex can snap them. You should check them with a meter on continuity. See if there is a connection from the relay post to the alternator post.

Then if all else fails, I would hit the alternator with a hammer. If it fires up, the brushes are worn out and it is time for a kit or a replacement. I prefer kits.

Mike

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

snipped-for-privacy@MSN.COM wrote:

Reply to
Mike Romain

did you replace the alt. with a new or used one? If its a used one the regulator could be shot (it's internal to the alt.). Check those wire connections like Mike suggested also double check the connections on the alt. even do a continuity check on them, I have seen a broken wire on the small stud (thinks its the field wire??) cause a similar problem on my XJ. Have you had the battery tested? a week alt. can cause a battery to discharge to a state where it will no longer hold a charge.

Snow...

Reply to
Snow

I installed a new alt., battery tested good is less than a yr old and holds a charge. Thanks for the tips, I will try them after work

Reply to
JRK58

You should check the "new" alternator again. My guess is you took off a bad one and put another bad one in its place.

Reply to
Jeff Strickland

That happened the last time I replaced the alternator, this time I had it tested right out of the box and it passed. Would a bad alt. act up intermittently?

Reply to
JRK58

Reply to
L.W.( ßill ) Hughes III

The battery had a full charge when the volt meter (thought it was an amp gauge) dropped from 14 to 12 or less. Actually it was charging when I parked it and not charging the next time I started it. Thanks

Reply to
JRK58

Well I purchased a volt meter today and here is what I found.

Batt. Post to post 12.61 Batt to relay stud 12.58 Alt post to case 12.36 running Alt post to case 12.56 off Yellow alt wire key on 12.23 key off 0.0 Tan/Black alt wire 0.0 key on 0.0 running

I have traced the Tan/blk wire 2 plugs back and get 0 volts. What should this wire be reading? If it should be hot like I think it does where does it go? Any help will be greatly appreciated. Thanks

Reply to
JRK58

Reply to
L.W.( ßill ) Hughes III

So the blk/tan wire should not have voltage? I pulled the alt and it tested good, I tried to exchange it for another but they said since it passed they wouldn't do it. Thanks for the reply Bill

Reply to
JRK58

Reply to
L.W.( ßill ) Hughes III

Reply to
L.W.( ßill ) Hughes III

It's actually an autolite alternator if that makes any difference. What should I tell the guy at Shuck's if he hooks it up to the tester and it passes again?

Reply to
JRK58

Bill, I bow to you as a jeep knowledge god. MIKE, seems to be a close second. all advice sounds good but everyone forgot to mention where he really went wront. He went to SCHUCKS for the alternator. Not anyone's fault, he didn't mention it till the end. Most people go through seven or eight before they get a good one..... Experience!!!! Anyway, when having electrical problems like bad grounds, etc...or cleaning terminals, ALWAYS apply some dielectric grease to keep the gremlins away for a longer time. thanks all! Robb

Reply to
Robb S via CarKB.com

Robb, I guess I shouldn't have gone to Shucks but is Autolite a bad brand? I did buy a new one.......John

Reply to
JRK58

Reply to
L.W.( ßill ) Hughes III

For starters you have bad/dirty battery connections according to those readings. A no load volt drop of .03V is significant, then the neg drop of .04V, well.....

All the readings like the alternator post to case (12.56) and battery post to battery post (12.61) must be equal with no load.

Did you ever try my ground jump suggestions? You 'sure' have the symptoms of a dead connection.

Without the proper ground path, the alternator will not turn on.

Mike

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

snipped-for-privacy@MSN.COM wrote:

Reply to
Mike Romain

Yes I jumped from alt case to battery neg., block to battery,firewall to block and to battery. Battery cables have tight clean connections but are old. Thanks........John

Reply to
JRK58

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.