My Riv. 1-wire alternator. Has done it twice in the last 3 weeks. GEN light comes on when I shut off key and engine runs on. Have to pull coil wire to stop it. Goes away when it cools off. Has never done it before. Both days it was hot out. I spoke with Jim Weise about this today. He says I need the diode in-line with my alternator. MSD's instructions do not mention how to do it with a 1-wire alternator. First time it did it was when I wired in my vacuum pump 3 weeks ago. But I totally disconnected it and it still did it. Then it stopped. So I figured I must have bumped a wire or something. Then it did it again today. Any thoughts?
Are you on the same tank of gas? Cheap fuel can cause run on. Most times if you leave the car in gear then turn off the key it will shut down. I know heat plays a factor in igniting the fuel in the cylinders even after the keys off.
Was the car previously an external reg or internal reg alternator (change around 1974). You should not be seeing a GEN light; you may have a wiring issue. Internal reg alts feed current from ignition, through the GEN light, and to the alt to help energize the alt. Once the alt starts up, it supplies its own energy, and the GEN light with 12V on both sides goes out. If the ign is turned off, some current can flow back thru the GEN light. One way to eliminate that is put a diode in the GEN light wire, but you should not even have the light connected to anything. The diode fix doesn't apply to a one wire. I do not like one wire alts, but they can be made to work. Whatever other wiring was provided must be disabled, which depends on the type of alt you had. One way that often works, is put a heavy load on things to absorb leakage current into the ign circuit. That might be a motor, radio, or light turned on. good luck, Bruce Roe
I've had a similar issue actually, however I have an internally regulated 12SI alternator. Mine does it when I turn off the car and don't catch the "lock" position in the ignition switch correctly, stopping just short of it or just past it. It never did this with the factory generator. I haven't found a solution - I'm leaning toward the ignition switch myself.
If you are still running the wire off the "R" terminal on the starter solenoid, make sure the nut didn't loosen up and let the wire connector contact the main power stud. I had that happen once. Wire would wiggle around a bit and occasionally contact the main power stud/battery cable. When you turn the key off the coil still has power going to it.
Thanks all. It was originally a 2 wire alt with external regulator on firewall. I went with a 1 wire because I could get a high amp alt, which I need. I'm not aware of a replacement 2-wire alt for a 69 Buick that puts out 90+amps. Anyone know where I can get one and what the application/part number is? I called MSD and they are stumped. They confirmed that the diode won't work on 1 wire alt. I need to plumb in a MOPAR ballast resistor. Oy. And I'm using a Ford solenoid due to hot start issue with the headers.
http://www.autozone.com/autozone/pa...-ijj0rZ9ci9i?itemIdentifier=82361_23521_9495_ 108 amps for 99.99
X2, I have a 94 AMP 12SI from Jamie. BTW, I do not have a diode installed. Never had that run on problem. Your GEN lamp is obviously being powered somewhere if it is lighting up. Find that wire and put the diode in it.
Not the answer to your question but: Leave the car in gear and shut it off, it should not run on then. Still find the issue, but this can save you some headaches. :TU:
Sean, He isn't experiencing dieseling, the engine keeps running. This can happen with an MSD. Current from the gen light circuit can back feed and keep the box on, so the engine keeps running even though the ignition is off. The solution is a diode in the indicator light circuit to prevent the back feed.
Duralast DL 7194-6-3 is a drop in once you swap pulley, install the proper pigtail avaialble from Autozone and others, and grind off a tiny little bump on the case. This is a properly clocked 12si from late '80s G and F bodies. (94 amps) You do need to do the rewire stuff exactly as indicated on George's website (Thanks George!) I have run no diode and have no issues with my MSD setup.
If it happened from the minute I installed the MSD I'd be sure what the problem is. But this just started happening after years of no issues. The diode is not the answer for 1-wire alts. That requires the ballast resistor. I'm stumped as to why it is intermittent and goes away after sitting for some time. I'll drive it tomorrow and if it happens I'll start checking wires.
Yardley, Do you have the harness to the old voltage regulator still connected at the regulator? If so, disconnect it, tape the terminals on the connector, and just stuff it back behind where it connects to the regulator.
Use the original "idiot light " wires and wire in a light. It can be a simple 194 bulb and socket. It can be placed next to the Alt or any where you choose. I saw this happen many times on a few tour vehicles with 454 chevys. It feeds from the Alt and stays running. The add on light cured it and gave a added warning light.
No. To make the 1 wire conversion you have to pull the harness from the regulator and run a jumper wire from the #1 terminal to the #4 terminal. The harness is not connected.
