View Full Version : Project Nazi Poltergeist - 81 Caddy alt/battery issues

2014.11.18, 16:01 PM
Okay, so the caddy has a new engine (1.8 8v out of an '87 Cabriolet), and it runs great. Prior owner of the engine said it only had 88k on the Odo before it was pulled.

New problem is related to the battery or the alternator, or both. Let me explain.

The alternator is adjust to it's tightest position, and the belt seems to be tight enough (to me), but there is a little slack. When its running, the alternator spins just fine, but it's been suggested to me that it may not be fast enough. I trickle charged the battery and it ran fine for approximately 30 minutes between two trips. at about 11:30 on Saturday night, as I was leaving ENRGZR's place, the truck died, and wouldn't restart. ENRGZR jumped me a couple times, only to have the truck die again. We pushed the truck back to his place, and he charged the battery for me overnight. I picked the truck up on Sunday morning, and it drove home just fine (approx. 3 miles).

I've read various possible issues online, such as exciter wires being picky, brushes and voltage regulators needing to be replaced, and there's always the chance that either the battery or alternator are dead. I'm picking up a new battery, this evening, but would like to nail this problem 100%. I don't want to kill a new battery, and I certainly don't want to get stuck on the side of the road, again.


I can certainly get pics of anything needed, and offer plenty of beer to anyone who wants to come help me solve this issue.

2014.11.18, 18:25 PM
Check the voltage on the new battery, it should be ~12.5V. Check it again with the engine running, should be ~14.5V (maybe a bit lower, but not a lot). With how quickly it's dying, I'd suspect the battery isn't holding a charge.

2014.11.18, 18:50 PM
Thanks for the idea. Old battery is at batteries plus being checked overnight. They wouldn't just let me exchange it under warranty, without testing it. So I'll have to wait until tomorrow.

Rabbit 16v
2014.11.18, 19:06 PM
Does the battery warning light function properly?

2014.11.18, 19:12 PM
I haven't noticed it on. Not even when I turn the key to accessory, before starting.

Rabbit 16v
2014.11.18, 21:26 PM
There is the problem. The battery light needs to function to excite the alternator.

2014.11.18, 21:30 PM
How might I fix it?

Rabbit 16v
2014.11.18, 22:05 PM
well you need to make sure the blue wire from the alternator has continuity to the plug on the cluster first. you can always be ghetto in the meantime. When I drove my car to work every day with no dash, I had to hook up a test light. one lead on the blue wire at the alternator and the other on the positive of the battery. light would be lit until I revved and light went out. I could hear the alternator charging at that point and would leave it running and go to work.

2014.11.23, 17:05 PM
Thanks for the info, Chris. I finally got a chance to look at the truck again, after a busy week.

I'll add pictures in a few, but I'm having issues with the wiring to the back of the alternator. Everything to the firewall/dash looks great. There are 3 wires that go to the alternator I have, and none of them are pretty. Two are connected to a plug, and one originally was bare and wrapped around a post (I believe this is the exciter wire). The bare wire was extended and had a round terminal added by me, to make a better connection. Was this correct?

My new question is, is this wiring setup correct, and could these couple of breaks be the real issue? Also, what's the procedure for checking everything once I get the wiring figured out? I don't understand the blue idiot light should work, but how can I check using a multimeter?

2014.11.23, 17:18 PM
Current setup for the wiring

Is the exciter wire supposed to connected to the bolt on the outside of the alternator case like this?

Power wire plug

Wires by themselves.

2014.11.25, 22:09 PM
Problem solved. I acquired an unmolested alternater wiring harness from a buddy in Lakehood. Spliced it in, and the truck runs like a champ. My multimeter is dead, so I checked the operation by unplugging the battery while the engine was running. The truck kept running, so it seems the new wiring was the key. I still don't get a battery light when the key is in accessory, so I'm doing the rev over 2k rpm trick to ensure everything is working. Onto the next link in the hose: shift linkage rebuild.

2014.11.26, 09:47 AM
The small terminal (blue wire) on the alternator should have continuity all the way back to the LED in the cluster, get a new multi-meter and track that down.

Rabbit 16v
2014.11.27, 23:39 PM
^^^WHS. also punch the previous person that grounded the exciter wire to the alternator case.

2014.11.28, 12:45 PM
Thanks, fellas. When I get a new multimeter, I'll work on finding the cause of the LED not working. As for punching the PO in the face, I'll pass. I like my LEO job. Felonies aren't really my bag.