89 z24 charging problem.

[HotFoot]

This started weeks ago, with the battery light coming on albeit very dimly when the truck
was first cranked, and then would "fade out" after revving the engine a little. Pretty soon however
the engine started running really really rough almost like it had jumped time, and the battery light was
on once again, the voltage drop causing the engine to run poorly. I figured it was the alternator, but no
new alt. still not charging, old alt. tested good, battery good. I have yet to find a fusable link at the + battery post,
but what i do have is connectors that all tested good for continuity on the meter. All the alternator connections
are nice and tight, heck i even replaced the - cable and took the + cable completely out and inspected it...
Iam completely stumped and i need this thing back on the road by monday so i can take the kids to school,
and i aint got the money for a mechanic.... I need an expert's help. Thanks.

[longtooth]

Well lets see. The belt is tight, both the alternator and battery tested good. I am a little uncertain if you replaced the battery cables.

But if you replaced the cables also I would be looking to see if you have a small coolant leak dripping into the alternator causing a bad connection with the brushes.

If no leak found put a meter on the battery with the engine running and watch the voltage and wigle the wires indavidualy. If you get a jump or drop in the voltage you could have a wire with a internal failure.

[HotFoot]

Yeah i forgot to mention two things, 1 the starter has been giving me engagement issues for sometime, and of course the + cable connects to it, but not thinking thats the problem, and 2 i did have a coolant leak, but as i stated the alternator currently in the truck is new. but is there something else electrical the coolant could have affected? IE: relay, module, etc. etc.

PS I checked the batt. with a multimeter both off and running, and when running it's drawing down.

[LEMHEAD16]

Replace Negative Battery cable the runs from battery to Chassis ground. It really sounds like a bad ground issue to me.

[jdansmith]

Neg. ground would be suspect, is their any chance at all coolant got into the new alt.?

[longtooth]

I would replace both cables. They can cause problems even though they look ok.

[HotFoot]

Got it! It was a strange green two wire connector on the starter/alternator side in the engine bay that had a fuse plugged into the end of it. somehow the fuse had popped out and was laying on top of the motor mount! What makes it strange, is that it just hangs there coming out of the wiring harness instead of being on the firewall or fender or anywhere else you would expect to find something like that Nissan..... Gotta luv em

[jdansmith]

Glad you found the problem and thanks for letting us know what the issue was.

[Saudade]

Got it! It was a strange green two wire connector on the starter/alternator side in the engine bay that had a fuse plugged into the end of it. somehow the fuse had popped out and was laying on top of the motor mount! What makes it strange, is that it just hangs there coming out of the wiring harness instead of being on the firewall or fender or anywhere else you would expect to find something like that Nissan..... Gotta luv em

On my 86.5, it a diode, not a fuse.

[HotFoot]

Got it! It was a strange green two wire connector on the starter/alternator side in the engine bay that had a fuse plugged into the end of it. somehow the fuse had popped out and was laying on top of the motor mount! What makes it strange, is that it just hangs there coming out of the wiring harness instead of being on the firewall or fender or anywhere else you would expect to find something like that Nissan..... Gotta luv em

On my 86.5, it a diode, not a fuse.

OK, it's a diode, although i thought the alternator diode is actually inside the alternator . Frankly, it could be a hickey, a doomaflage, a whatchamacallit, or a thingy. Whatever the case, all that matters is my truck is running again!
And BTW, Thank-You for wasting 5 minutes of my life, from me getting notification that someone had posted in my thread,
only to get here and find something written with little or no value whatsoever. MERRY CHRISTMAS!