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R6_80922 · Joined: 20 Sep 2004 Posts: 1

I replaced my alternator today got it all put back together and was doing fine at idle. I gave it some gas and made a loud skreech in the engine. Tried to shut it off but had to unhook the battery. Would start and stop when I turned the key but would not shut off when it hit the high rpm and made the noise. First time owner and need some advice. The engine is very low miles around 40k. Did I hook the alternator up right? I hooked the main lead into the starter where the battery hooks in.

The fan belt that was on there was tight and hard to get on with no adjust ment after installation.

Any help would be appreciated!

Lizard · Posted: Mon Sep 20, 2004 9:38 am Post subject:

to make sure we understand this correctly,

you can start the car via the key, and you can turn it off via the key. however as soon as you rev the car up it takes control and you can no longer turn the car off with the key and it makes a loud screaching sound when this occours. is that correct?

on the Alt there should be 2 wires a small one which goes to the small post on the alt, and a large wire which by factory went by the starter and then up to the battery, but I dont see how getting therse backwards would cause this type of problem
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3 928s,

ponchojuan · Joined: 20 Jul 2004 Posts: 51 Location: Boston, MA

There should be three wires, including a ground. Mine is a braided, uncoated grounding strap. Tou have to uset these since the bracket has rubber bushings. Be sure these wires are mounted to the correct posts, and not touching any metal outher than the posts..

I'm assuming this is an electrical noise and not mechanical ( which would stop when you shut down the engine.) Never heard of an electrical "runaway" before. Possibly the grounding strap is missing and not grounding out the ignition when the key is shut off. ( only a wild -ass guess).

The belt tolerances are close and the alternator has to be adjusted correctly or you will get a nasty screech when the bracket hits the alternator blades or the pulleys touch.

Also, if the alternator is too tight, the mounting bushings will put stretched and the pulley will be out of alignment; yet another opportunity for squelling.

Then of course, there is the "too loose" squel iunder engine rev.