Okay, I've read just about ALL of the posts on this issue, and here's what I've got/ replaced/ done this far.....
Was running funky, code was P1367 (something close to that, but it threw the crank or cam sensor code) so I replaced them. (OEM) Didn't change anything, still ran crappy, but I delt with it, (2,500 mi on a FRESH motor)
Then, it stopped charging....(freshly charged batteries, carried 3 at all times)
Assumed it was a regulator, bought an alternator, then found the decal which told me it was in the PCM......
Returned the Alternator.
Had my old one checked on an actual tester, AND while IN the TJ...same result.
Under 100A+ load, 14.2 (blower, brights, radio, wipers, RWDefrost)
At idle/no load, 14.5
Tested ON and OFF the jeep. But if the gauge didn't read it was charging....it wasn't.
Then I buy A PCM, now, it runs "better" but periodically idles like hell, but still doesn't charge.
A this point,
FORTUNATELY I loose my temper and HIT, yes, HIT the old alternator with a hammer....IT CHARGES!! WTF?!?
Okay, not always, but when it's NOT charging, I pull over, raise the hood, give the alternator or a/c bracket a good beat down, and she starts to charge again.....but it's only temporary...
I'm with the guy who said, I'm bout to go buy a pistol and shoot myself!?! I refuse to have someone else tell me it's something I didn't check. NEW cables, GROUNDS, checked all of the breakers and connections, all new star washers at the grounds, hosed down with the protective spray, every plug is now clean and has new dielectric grease, pulled the a/c bracket and even cleaned the place where it bolts to the motor JUST in case the alt grounds to the bracket or the motor..... I've also added "new" temporary grounds just to be sure I didn't miss one....l. Omg PLEASE HELP?!?
I'm sure you don't want to hear this, but generally if a problem is fixed by doing a "percussion check" on it then the issue is caused by something sticking (highly unlikely here) or an intermittent connection. Judging from what you describe, my primary focus would be on the plug on the alternator for the field driver and voltage regulator signal. Next time the Jeep decides to stop charging, instead of whacking the hell out of the alternator, try wiggling the plug on the alternator -- if nothing changes, wiggle the wire harness. Keep working your way back on the harness from the alternator toward connector C103 (the large black connector on the firewall), then on toward the PCM.
Thanks for the response mukluck, I'm definitely down with the phrase "percussion test" however, as far as the connections go, I had to pull them all apart to replace the PCM and the one time I did actually replace the alternator. I think I forgot to mention that at one point, I did replace it just to see if that was the cure, and it didn't chance anything. I also didn't want to start beating on a brand new $140 alternator that wasn't going to fix the real issue...so, I actually had checked all of the plugs, grounds, connections on every inch of the motor....including plugs that were underneath the TJ just to be sure that I had been through in my quest to "renew" the integrity of 99.9% of all of my connections.
Now, the one thing I have NOT tried is the Wiggle test.....so I'll be sure to try that and bring back an update later today when I run out of band-aides from beating my head up against the wall..... Plus it's -15° here today, so I'm not exactly in a rush to chase out there to get discouraged about my day this early in it....lol
Thanks for the ideas though!! Please know ANYTHING is VERY much appreciated!!!
Anyone else have suggestions, please feel free, I'm no master tech, but try to be as thorough as possible before I take it to an ITT tech that knows less about JEEPS than collectively than us actual Jeepers do!
What is most likely happening is you have carbon buildup near or around the brushes (or some other mechanism not fully understood ) in your alternator causing an intermittent short. I've now seen this on 4 separate occasions on '97 and '98 TJ's. In each case replacing the alternator solved the problem, permanently.
Like I told the last guy, pull your alternator and have it tested. When it passes, replace it anyway.
Thanks for the info, i actually thought it might be the brushes hanging up as well, funny thing is, (I know I was a tad vague) but I had actually yreplaced the alternator with a new one, and had the same issue. Luckily for me, I worked at this particular part house for a few years back in the day, and the same owners allow me to use new parts to test...in any event, I didn't beat up on the new one, but had the same issue, and thought it would be best to save the cash and assume it was something else.... I've had the old one (still in the truck) tested in, and out of the jeep, with the same result, it apparently charges, as long as its NOT in the jeep....unless I "percussion test" it.... So far, doing that has saved me from having to worry about carrying 3 extra batteries with me at all times, but still frustrating that I've owned it for 14 years, and this year, she's falling apart....
Again, thank you ALL for your input!!
Sorry,, that's what I was just explaining before, I tried that,, with the same results.....so I took it back. I didn't want to percussion test the new one and destroy the case to make it unreturnable..... What are the chances the new one I got, was bad?
Based on what you are saying tapping the alternator fixes the charge issue, temporarily, and that it is consistently doing so (meaning it is not a "fluke"). If I take this at face value it is a very hard symptom to ignore.
Seems just as likely the new alternator simply did not charge mimicking your current symptom of intermittently charging then your current behavior of tapping the alternator to make it charge is coincidence.