QuestionQUESTION: I have a friend that had the engine rebuilt in his 1972 GMC Pickup and between the two of us we have cleaned, painted, and reinstalled the entire underhood engine compartment components over the past two years. This process included removing basically everything down to the frame from the cab forward (hood, fenders, engine, transmission, radiator, etc...).
We now have everything tuned and running well. The only issue that has been noticed is that the red resistance wire (white on some chevy/gmc trucks) gets really hot....to the point of not being able to hold onto it for more than a few seconds. This is the wire that runs from inside the cab along the firewall then splits off into two yellow wires (which never get warm at all) with one yellow wire going to the starter and the other to the ignition coil. One time it got so hot it started smoking. I'm fairly sure being a resistance/resistor type wire, it should get warm, but not smoking hot. I know the wire gets hot when the engine is running, but I think it may also get hot when the key is turned on also.
He really doesn't want to drive it for fear of it catching fire and burning down...which would be bad with all of the work and money that has been put into it lately. Things we have tried include:
1.) Different ignition coil.....old used one
2.) Different rotor button......old used one
3.) Disconnecting the voltage regulator
4.) Disconnecting the alternator....since it seems to get really hot in a short time period
The only other thing that might help with this issue is that for some reason when the headlights are turned on, the turn signals are dimly lit and the gas gauge starts dropping. It seems to help to turn the headlight knob all the way down. Is this related to the other issue or a separate issue?
We have tried several things and have had no luck at all. The goal is not to spend alot of money on a random chance where it's not needed, but instead to just fix the problem at the source.
Sorry for being so long, but I was trying to be as detailed as possible.
Thanks for any help and advice!
Greg ~
ANSWER: If the resistance wire is getting smoking hot it is because there is too much current passing through it. Is there anything connected to the tach terminal of the cap like anti theft or tachometer? If there is this could be causing a current draw. Check the primary winding of the coil with an ohmmeter. The resistance should be about a half an ohm. Let me know and we will go from there.
Brad
---------- FOLLOW-UP ----------
QUESTION: This truck is pretty much stock except for an aftermarket radio and amp that was installed many years ago...so no extras like anti theft or tachometer in this truck.
The primary winding of the coil measured 1.7ohms by measuring with all of the wires disconnected from the coil and putting the red meter lead on the + side and the black lead on the - side of the coil.
Also, this truck has the old points style distributor not the newer HEI electronic type. For this reason, I'm assuming it doesn't have any type of ballast resistor since it has the resistance wire.
I forgot to say earlier that we have tried a different condensor (old used one) without any luck.
Thanks for the quick reply!
Greg ~
ANSWER: The yellow wire that runs to the starter. Which terminal is it connected to?
Brad
---------- FOLLOW-UP ----------
QUESTION: It's connected to the "R" terminal which is the outside terminal closest to the frame rail.
AnswerOk, lets go a step at a time.
1. Turn on the key and see if the wire gets hot. If it does remove the yellow wire from the R terminal of the solenoid. With the wire removed check the resistor wire again. If it is cool now you have a defect in the starter solenoid.
2. If the wire does not get hot when you turn on the key with the yellow wire connected then start the engine. If the wire gets hot now, with the engine running disconnect the yellow wire from the R terminal. If the resistor wire cools down the solenoid is defective.
See what happens and let me know.
Brad
