Alternator Question

[Robbie_Cantey]

I have a 1990 ford Festiva, I think iam having problems with the alternator but not sure. This is what it is doing: When starting the vehicle it run's fine long as the battery is charged, but the alternator is not producing power. after rev.. the engine to about 3,000 rpm the alternator belt starts to slip at idle, now the alternator is charging at 14.5 volts and if you rev it at this point it will start to burn the belt off. Turning the car off fixes it until you rev it back up. now i changed the alternator and it ran fine for about an hour than it started the same old thing again. Iam thinking it's some type of short in the wiring and even a coulple mechanics told me its possible but not sure. What should i do to find the problem

[FB71]

what does the 'Charge' indicator lamp do during these events?

[Robbie_Cantey]

Charge indicator lamp doesn't seem to come on the dashboard. I thought it was the alternator until i put a good one in and it still caused the problem

[Robbie_Cantey]

There also 2 connectors that go to the alternator, i is plug in that has 2 prongs the other is nowhere to be found but on the alternator it has one prong for it to plug into

[therris]

I think I had this problem with my first Festy. Couldn't figure out why my battery kept dying. Alternator charged fine when I would test it and all. Turns out the alternator belt was so glazed that it would charge fine at idle, but during driving the increased rpms would cause the belt to slip and pretty much not charge the alternator at all.

[scitzz]

seems to me that the belt has no connection to the wiring, so the belt, or mounting of the alternator, or another pulley is the problem. Is the belt tight enough? It should be less than a 1/2 inch of deflection, without being too tight.

[WmWatt]

Cheaper to swap belts than alternators.
A slipping belt usually chirps like a bird.
I'd try adjusting the belt and checking the voltages again.
Don't overtighten the belt or it will burn out the bearings on the alternator.
Burnt bearings usually make a squealing sound like a pig.
If you have to overtighten the belt to get the alternator to charge replace the belt.
When you changed alternators you got a new finish on the pulley with a different co-efficient of friction which makes the belt sound suspicious.
They might give you a refund on the new alternator if the old one is still good.

[Robbie_Cantey]

The belt is on tight enough i checked the tension on it. there something else going on

[jglutz]

Cheaper to swap belts than alternators.
A slipping belt usually chirps like a bird.
I'd try adjusting the belt and checking the voltages again.
Don't overtighten the belt or it will burn out the bearings on the alternator.
Burnt bearings usually make a squealing sound like a pig.
If you have to overtighten the belt to get the alternator to charge replace the belt.
When you changed alternators you got a new finish on the pulley with a different co-efficient of friction which makes the belt sound suspicious.
They might give you a refund on the new alternator if the old one is still good.

Yep...I would solve the Belt problem first...when the belt is off...the water pump and alt should turn freely.

Remember...an alt does not produce fre energy...when ever something is turned on (head lights) it is harder for the engine to turn the alt. What ui mean... ther could be some excessive electrical load making it very hard too turn the alt and the voltage reg just hasn't failed yet.

Aslo measure the battery voltage when it is disconnected...it should be 12.5VDC... for a convential battery (6 cells)...if it reads 10.4 volts...or some multiple of 2.1 volts lower....it could be a blown cell.

I've seen this a bunch of times....a battery failure is followed shortly by and alt failure...or...an alt failure is shortly followed by a battery failure.

[roycehof]

Hey, You should have the voltage regulator wires attached (the clip on connector) and the lead that goes to the battery (which is a bolt on connection). Make sure that is all good. Unhook the single lead from the alternator and make sure it is reading the battery voltage. If it isn't, this need to be fixed first.

[Robbie_Cantey]

Thanks guys, finally got it up and running. It was the belt being too loose, but the bolt that tightens it up was striped out so after awhile the belt would become loose again and start squealing. So i replaced the bolt, now everything is running fine. Now to get my money back from the other alternator.

[kzbill]

it's the simple thing again

[FB71]

:lol: