Forum Index
Jeep Horizons HomeLinksJeep Horizons Tech Write-upsJeep newsLand useContact

 Watched TopicsWatched Topics   FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

-SOLVED - Electrical Gremlins - Alternator won't charge batt


 
Post new topic   Reply to topic     Forum Index -> Grand Cherokee Forum
View previous topic :: View next topic  
Author Message
ZJ_Ras
Member


Joined: 19 Apr 2008
Location: San Diego

PostPosted: Sun Feb 14, 2010 8:10 pm    Post subject: -SOLVED - Electrical Gremlins - Alternator won't charge batt Reply with quote

OK, so my 95 ZJ 5.2L V8 got to the end of the driveway the other evening and just died. Starter turned quickly, but no go. I ruled out the fuel pump and replaced the fuel filter because it was due anyway. I tested the ignition coil which was good, than checked for spark from it for 30,000 volts which was successful. Next I checked for spark at one of the plugs and the damn thing started right up! My jump starter has an alternator test mode that said the alternator was bad.

It tested OK at AutoZone, but was making some funny noises and it was about time for an upgrade so I changed that out and installed a 136 amp reman for a 98 ZJ 5.9L V8 and the engine wouldn't start again. I pulled the whole battery/alternator/starter/ignition coil wad of wiring and found no issues. I reinstalled it all and again (with all connections clean and tight), the Jeep started right up.

So, as I was poking around in the engine compartment, I happened to find out that the wire from the ignition coil (the 30,000 volt one) was shorting to any nearby metal in the engine compartment via a crack in the insulation when my handy internal volt meter yelled AHHHHHH SHIT!!! So that explains why it would sometimes start and sometimes not.

I swapped out the wire this morning and the engine starts and runs fine now, but will not charge the battery. The battery checked out fine at the store and was reading 12.54 VDC when I brought it home and stayed over 12VDC with the engine running and headlights and fog lights on, but after driving about 15 minutes, the lights dim and my voltage drops until the lights are barely on and the instrument panel stops working because the voltage is so low. I had just over 7 VDC after 15 minutes of driving. The engine ran fine, but everything else was about dead.

I'm thinking something may have gotten fried when the ignition juice was shorting to the chassis (mostly through the metal air conditioning tubing).

I also replaced my battery terminals in this process to unclutter the add-ons and because the old terminals were getting pretty chewed up. Those check out good with battery voltage from + to chassis the same as + to - and 0 ohms resistance from - to chassis so I know the terminals are conducting well.

What else should I be checking and where?

I know the alternator is voltage regulated by the ECM in my Jeep and the new alternator was labeled saying that it was externally regulated so that is right.

How do I test my charging relay?

Is there anything else it might be?

Thank you for your help.
_________________
Jon

'95 ZJ Orvis Edition 5.2L V8 with 210K+ miles Featuring a 2" Budget Boost with Skyjacker Hydro Shocks, 242 T-case swap, JKS Quicker Disconnects, 30x9.5s, cold air intake, throttle body spacer, 136A alternator and a DIY roof rack spare carrier.


Last edited by ZJ_Ras on Mon Feb 15, 2010 11:51 am; edited 1 time in total
Back to top
View user's profile Send private message
IBTJn
Moderator
Moderator


Joined: 31 Dec 2004
Location: Just Outside of Portland, OR

PostPosted: Sun Feb 14, 2010 8:51 pm    Post subject: Reply with quote

One of the most neglected connections in the electrical system are the ground points. Just for giggles and laughs, make sure you clean them at least on the block, chassis, and any place else you see. Actually, it would also explain why you wouldn't be charging. Not saying that's the problem, but more often than not folks key on the hot lead, and neglect the grounds. They are just as (if not more) important.

When was the last time you actually replaced the entire cables? I only replace the terminals in a pinch. I always replace the cables with formed/molded type. I learned years ago that sometimes those replacement terminals don't work worth beans, are corrosion magnets, not to mention don't last as long.

It could very well be you fried one of the capacitors in the alternator, or even the voltage regulator. If everything else is good I'd pop it out and have them check it again.

Just a couple thoughts that come to mind.
Back to top
View user's profile Send private message
ZJ_Ras
Member


Joined: 19 Apr 2008
Location: San Diego

PostPosted: Sun Feb 14, 2010 10:09 pm    Post subject: Reply with quote

Well, I had the entire wiring system out and replaced it, all connections are clean and good, all wires had 0 or near to 0 resistance. so I have ruled that out. That includes the grounds.

The alternator is new so that is off my list as even the old alternator tested good at the store. The voltage regulator is a function of the PCM/ECM and I think would have fried the whole chip if that was the case.
_________________
Jon

'95 ZJ Orvis Edition 5.2L V8 with 210K+ miles Featuring a 2" Budget Boost with Skyjacker Hydro Shocks, 242 T-case swap, JKS Quicker Disconnects, 30x9.5s, cold air intake, throttle body spacer, 136A alternator and a DIY roof rack spare carrier.
Back to top
View user's profile Send private message
ZJ_Ras
Member


Joined: 19 Apr 2008
Location: San Diego

PostPosted: Mon Feb 15, 2010 11:48 am    Post subject: Solved! Reply with quote

Well, that short happened to send mucho voltage not only through me, but also through some other things which fried a couple fuses and compounded the issues. Replaced two 60A Maxi fuses in the power distribution box under the hood for alternator outputs 1 and 2, along with the fuse behind my radio and two in my amp so now everything is back to normal! headbang
_________________
Jon

'95 ZJ Orvis Edition 5.2L V8 with 210K+ miles Featuring a 2" Budget Boost with Skyjacker Hydro Shocks, 242 T-case swap, JKS Quicker Disconnects, 30x9.5s, cold air intake, throttle body spacer, 136A alternator and a DIY roof rack spare carrier.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic     Forum Index -> Grand Cherokee Forum All times are GMT - 8 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Visit links4jeeps.com for write-ups, forums and clubs




Jeep®, Wrangler, Cherokee, Liberty and Grand Cherokee are copyrighted and trademarked to Chrysler LLC.
jeephorizons.com is not in any way associated with or endorsed by the Chrysler LLC.
All other content is copyright Jeep Horizons 2004-2008.
Tech write-ups Links Discussion board Land use News Site Map Terms of Use

Powered by phpBB © 2001, 2005 phpBB Group