Ok, I have my new 350 running in my 72 'lark. I have an MSD 6 box and an HEI distributor that I am using for a pick up trigger only. I have an external voltage regulator. When I first started my engine it would not shut off with the key and my generator light would bo on when the car was not running. I then installed the diode that comes with the MSD to my brown wire going to the regulator and bingo, the car turned off and the generator light went off when the engine was off, all was good. Two days later I turn off key and engine continues to run, my voltage gauge turns to "0"and tach turns off. I had to turn down the idle screw until it quit, and now the generator light is on in the dash when the engine is off. I am at a loss as to why this happened. I currently have the MSD getting the 12volts from my fuse block on the "IGN" feed. It has 12 volts now with the key off, I also have 12 volts on my old positive coil wire. Is this normal???? Where can I look to find the voltage leak? Thanks Tim
Tim, All the 12 volt wire does is turn the box on and off. You are supposed to use your original + coil wire for this. The box gets it power for the ignition directly from the battery. Are you sure you wired the diode in the correct direction?
Larry, I was hoping you would respond. Yes I put the diode in correctly, like I said it worked great for two days and then went bad again so I thought maybe the diode went bad, I replaced that and still no go. I hooked it into the top wire in the regulator(small brown wire) with the stripe towards the regulator. I have a small amount of voltage on this brown wire with the ignition off. I also used the original + coil wire and this did not help. What now?
Tim, Use the original coil+ to turn the box on. Make sure there is voltage(coil + wire) with the key in the on/run position, and no voltage in the off position. The external voltage regulators have 4 terminals which are numbered. Install the diode in the wire coming out of the #4 position.
Larry I did try hooking up the MSD to the old coil wire. It has 12volts to it with the key in the off position????????? I also have power to the fuse box on the extra terminal that says "ign" and the one that says "acc" with the key on or off! When you say terminal 4, is it the farthest wire that is "up" (small brown wire) or the last one that is down??? I can't understand why it worked for three days then it wouldn't shut off???? The generator idiot light is also on with the key turned off but once the engine is started it goes off!!! Tim
Ignition switch, you should not have power to the coil + with the key inthe off position. That is your problem, not the regulator wire or diode.
Ok, so how do I check that, any other areas to check for power that shouldn't have it?Do I need to take the steering wheel off to put a new ignition switch in? Where do I get an ignition switch? Thanks Tim An
Tim, Not the lock and key. Ignition switch wiring is at the base of the steering column. I'm not sure how to troubleshoot this. Maybe someone else can help. The power is not being cut when you turn the key off. There is some linkage inside the steering column, and a switch or relay at the base of the column. Take a look at these areas, maybe something obvious will jump out at you.
Ok, thanks. I wired up a few extra items before I put the engine back in and I did not have the luxury of the battery being in the car at the time to check power sources. I added an autometer tach,voltage and oil pressure gauges. TH400 kickdown switch which I took power from the existing wiring. I added a dimmer switch for my switch pitch, got power from the extra accessories terminal. I will take a look at the steering column. Thanks Tim
BadBrad :laugh: :laugh: Remember what JW said about political threads. Remember that thread that started out with Martha Stewart, and ended up being a full blown war :laugh: Lets focus on the problem Tim is having.
Tim, Larry spoke to me about your problem and I believe that your problem is with the ignition switch. It appears that the ignition switch is not shutting off fully and still has partial power going through it. When you go to install the ignition switch be careful to adjust the trolley system(basically the rod that runs from the key tumbler down to the ignition switch. You'll find it runs on top of the steering column). If your switch is original,I would suggest replacing it right now.
Check the diode. Diodes can go bad, even out of the box. Try another one or just disconnect the diode and wire for test.
Ok, are you talking about the replacing the switch on the steering column, not the key switch right? If so where can I get one, is there other ways to check this switch? How do I get at this switch? Mike, I have tried another diode and it still runs. Thanks Tim
Tim, to replace the switch,you have to drop the steering column down to gain access to the switch. You will see the ignition wiring harness going to this switch. The switch is attached to the column with two screws which are 5/16'' and must be removed to remove the switch. When you are installing the new switch,make sure you connect the wire rod to the switch(this wire rod comes from the key tumbler and follows along the top of the column). Be sure you adjust the ignition switch correctly,otherwise it will not function properly.Make sure that the switch functions in all the quadrants(accessory,stop,run,start). P.S. switches can be found at any auto parts store-just make sure you get the right one for your car(there is a difference between a column with tilt wheel vs. a column without tilt wheel). With a test light you can test to see if your old switch is working properly-you should not get any power with the switch in the off position. Good Luck!
Ok, I bought the switch and will install it tonight. I will let you know if it works. I want to thank everyone for all your help. Tim
I agree. Check the diode. When such a device dies, it typically shorts, causing a return to the previously experienced symptoms. If the diode is shorted, you might want to use a larger current diode, connected the same way as the original.
