Ballast Resistor gone bad??? Please help.

[Guest Grenade300]

My alternator recently shorted out and took the positive side fusable link with it. I replaced the fusable link and the alternator. The car had a real hard time running when I started it up after that. So I popped the hood astarted looking around for the problem.

 

When I touched the ballast resistor it was so hot that now have no fingerprints on two of my fingers! None of the other wires were hot and the heat seemed to be coming from the iternals of the resistor.

 

When I ohm'd out the resistor it was reading about .3 or .4 mA.

 

What should the restor be reading? Is it possible that the alternator shorting out caused the resistor the fry?

 

Thanks,

Scott

[Pop N Wood]

Sounds like something shorted out DOWNSTREAM from the ballast resistor causing excess current through the resistor.

 

Really, you should be able to jumper over the ballast resistor and the car will run fine until the points get pitted to the point of no longer working.

 

You need to be careful, because whatever is shorted may have been the cause of your fusible link/alternator going out in the first place. Fix the short before you burn up another alternator.

[Guest Grenade300]

I think your right, I did some poking around with a multimeter. It looks like to coil is fried. Gonna replace the coil this weekend. I'll keep ya'll updated.

 

Thanks for the help.

 

Scott

[z bomb]

Got to this a little late but...

Yeah I've found that a bad coil or wrong wiring (like attaching the tach to the coil on a MSD system) going to the coil will cause the ballast resistor to get really hot.

 

But to find out if your ballast resistor goes bad, the car will only run while trying to start. Putting the key from start to run position shuts the car off, due to the fact that on start, the current bypasses the resitor due to starter draw.

[Guest Grenade300]

Ok, I'm at witts end and really need some help. I replaced the coil and took the ballast resistor out and put a strait through wire for testing purposes. Same problem (It's a real battle to even keep the car running). After a lot of looking around, I thought that the engine could be having fuel starvation issues (I check the spark and it is definately good).

 

If I am correct, then the fuel pump should be on when cranking the engine. I'm not getting any volts on my multimeter at the fuel pump when I am cranking the engine. I traced all over the car and found there is no voltage going to the wire that activates the fuel pump relay. When I put a direct hot into the wire that activated the fuel pump relay and try to start the car she runs a little better, but it is still a real battle to keep running. I traced the source of that wire and it leads to a split where it goes to the voltage regulator and the alternator.

 

By the way when I replaced my alternator the new one looked a lot different than the old one, but I figured it was just made by a different company. The hook ups were the same.

 

So, here's the big question: On the alternator there are a total of 4 wires. white/red-going to the battery and fuse box

black-leads to ground somewhere (ohm'd it out)

Then there is a connector that plugs into the back of the alternator. This plug has a black/white wire and a yellow wire (which is the one I spoke of that needs to be hot to activate the fuel pump)

 

What are these 2 wires for? When are they supposed to be passing current? May be I got handed the wrong alternator?

 

I think whatever is screwing up the fuel pump is also screwing up the engine running as a whole.

 

Thanks for all the help so far guys,

Scott