schwank

Our 83 ChumpCar runs now for the first time in over 4 years. However we have a weird condition.

The car starts and idles great with no alternator belt. But as soon as the alternator belt is hooked up, it will crank over but never catch and fire up. This is with the alternator wires hooked up regardless. Same condition with 2 different alternators.

Thoughts on the cause?

Wipeout

How is tension on the belt? Wasn't paying attention when you/James hooked the belt up.

Can't imagine that's the issue with two different alternators, but...

Van

Maybe a short in the field coil wire or something... When the alternator is spinning, something is causing the ignition to short out?

Wipeout

Field coil wire...small blue wire, correct?

Jfrahm

Yes I suppose a short or possibly a voltage regulator problem that is messing with the ECU.

Van

It's a small blue wire on VW passats...

schwank

Hmmmm. Weird. Guess we'll have to do some more troubleshooting tomorrow. The thing just stumbles but never starts when the belt is on... but literally fires right up as soon as you take it off.

m73m95

does it fire up and run with the both wires unhooked? (you said something about the wires, but I don't understand what you're saying)

schwank

What I was saying Mark is that I did not try what you suggested... only WITH the wires connected.

m73m95

ahh ok ..... well I agree with what the others have said. You have a short. Finding it is the fun part.

schwank

Just to close this one out, we got it working last night. Turned out to be a short in the exciter wire. While the fix is not great, it is stable and we'll be out on track, actually charging the battery.

Now to find the other 10 shorts in the car