Charging Issues

[FORSFED]

I tried helping my cousing with his car today and came up clueless. Basically what's happnening is the alternator appears to not be charging while the car is running. Key on/car off the voltage reads 11V and with the key on/car on the voltage reads 11V, no change. So assuming it was the alternator we swapped one in from his other car, which we know for a FACT charges properly (13.5V on the logger). There was no change, car still read 11V. The alternator fuse and relay are both fine to my knowledge, so what does this come down to? Wiring? Just for shits we threw the first alternator in his other car and that again reads 13.5V on the logger so we know it works. But what would cause it to not charge the system in the first car?

-Steve

[Kevin 1G Drummer]

Check for a corroded connection somewhere in the harness for the alternator. I had an old Nissan truck a couple years ago and I ended up having to replace the alternator. In the process, I also found a small wire bundled in with the harness that was corroded and wasn't allowing the new one to charge. So I fixed that, and everything was good as new.

[FORSFED]

That's one thing I was thinking might have to be done is go through the harness. One more question I have is what is the plug on the back of the alternator with the two small gauge wires? Is that the regulator? I have a hunch if it is that maybe those wires are bad along the way, not allowing the thing to charge...

[tim]

Have you checked the output right at the alt with a volt meter?

[FORSFED]

That is how I came up with 11V....

[tim]

That is how I came up with 11V....

Sorry, I thought you were basing it off what the logger was telling you.

[FORSFED]

No, in the red car we were using the voltmeter. In the donor car the logger was hooked up.

[gflo383]

maybe you have too small of an underdrive pulley?? if your checking the voltage @ the alternator, it seems as if its spinning to slow. does it make a difference if you rev the engine? i remember you saying something about this before.... I hate electrical problems. times like these when i wish i knew an electrical engineer ; )'

Joe G/4SFED-Z

[FORSFED]

No underdrive pulley on it, they are all stock. Also makes zero difference revving the engine, it just stays at the battery voltage...

[Kevin 1G Drummer]

Kinda sounds like a voltage regulator issue, or wiring in the harness for the regulator.