New alternator installed- burnt up wiring harness to starter., New alternator installed- big problems followed Options

[lonewolfe]

I just finished installing a rebuilt 75amp alternator and new voltage regulator today. What a big pain in the butt this job was. My car is a 1972 914/4 1.7L. Anyhow, I started the car and the generator light was no longer staying on. The car ran great for about 20 minutes then all of a sudden the car stopped running and tons of white smoke was bilowing out from under the car and the engine compartment. Everything electrical stopped working. After it stopped smoking I got under the car and the wiring harness that goes from the alternator to the the starter was completely melted. The other wires from the harness that go the relay board seem to be fine and were not hot to the touch. So, obviously I need a new alternator/starter harness but I don't know why this happened. I hooked up everything exactly as it was hooked up before. I did use a different wiring harness that appeared in much better condition than the one I removed with the old alternator.

Could it be that the rebuilt alternator was defective? Have any of you had something like this happen before? I wonder is the starter and alternator are both destroyed now?

[dlee6204]

Usually this happens because there is a stud on the back of the alternator that is too long. When you install the cover, it comes in contact with the stud, grounds it out, and fries the harness.

[McMark]

(IMG:style_emoticons/default/agree.gif) yup.

[lonewolfe]

I read about the long studs in McMarks alternator installation instructions. They were too long so I shortened them with a hacksaw. One thing I notice is the black metal inside of the alternator was sitting a little higher on one side than the other so the cover wouldn't sit completely flush. I bet there was some contact somewhere that caused this. Do you think it friend the alternator and the starter? It looks like my battery has no spark now too!

[Bob L.]

(IMG:style_emoticons/default/agree.gif) yup.

That was my first #%&* up on my 914... if you don't count paying too much for it. (IMG:style_emoticons/default/blink.gif)

[SLITS]

The wire that burned was the hot lead to the alternator. It is for sure the diodes in the alternator are toast.

The starter should be ok. Not sure if it would damage the solenoid from heat.

If your battery is dead, it could have shorted internally. You could always try charging it to find out.

Did the main cable to the starter from the battery suffer any damage?

[lonewolfe]

The wire that burned was the hot lead to the alternator. It is for sure the diodes in the alternator are toast.

The starter should be ok. Not sure if it would damage the solenoid from heat.

If your battery is dead, it could have shorted internally. You could always try charging it to find out.

Did the main cable to the starter from the battery suffer any damage?

The only cable damaged is the one from the alternator to the starter. So, I need another alternator. I bought this one a couple of months ago on EBay from a rebuilder company down in LA. I'll let them know about it but I doubt they'll do anything.