Since I can't find a 67 Diagram I'd thought I'd ask here... I am looking for what the wires that go into the voltage regulator are... Are they the same for say 1972? Just curious because the project I am working on has small (14g or less) wires on it while newer Buick's I've worked on have a 10g wire that ties in to the main junction... I'm a little concerned the wires on this one are too small and will cause problems down the road with a higher amp alternator... Thanks! Dan
Let me just go ahead and post the specifics, maybe someone has an answer... Car is a 67 Pontiac LeMans. Wiring harness is an aftermarket reproduction but is similar to stock in appearance. Alternator has been changed to a 12si. At first I wired it using the remote sensing feature and the charge light indicator. It worked great until I went to shut off the engine but the engine stayed running... I tried some alternate wiring methods including running the volt sensor to the post on the alternator but had same issue. The only diagrams I can find in the pontiac manual show a basic layout of the charging system. What I see is that the charge light wires go to the charge lamp then to the ignition switch. What I think may be happening is that there is a "backcurrent" through the charge lamp wire that is powering the ignition switch which is in turn powering the ignition system not shutting off the engine... I've run into an instance like this that required a diode be installed in one of the wires to the voltage regulator but I cannot recall what type of diode nor which wire - though I'm guessing it will be the wire that goes back to the ignition switch... Can anyone tell me if I'm on the right path here? Thanks Dan
Bingo Guess I was right... "If your engine continues to run even when the ignition is turned Off you are experiencing engine Run-On. This usually only occurs on older vehicles with an external voltage regulator. Because the MSD receives power directly from the battery, it does not require much current to keep the unit energized. If you are experiencing run-on, it is due to a small amount of voltage going through the charging lamp indicator and feeding the small Red wire even if the key is turned off. Early Ford and GM: To solve the Run-On problem, a Diode is supplied with the MSD in the parts bag. By installing this Diode in-line of the wire that goes to the Charging indicator, the voltage is kept from entering the MSD. The diagram below shows the proper installation for early Ford and GM vehicles." That is from MSD's website. Below this there is a diagram showing the diode to install and where to put it.... Radio Shack, here I come...
