I added a MSD Ignition controller 6AL. Easy install, no problems starting or turning off the 350. No gen light on dashboard, all was good. I then installed and heavier gauge wire to both neg and pos with new terminal connections. Now when I start the car, no problem, but when turn it off the car continues to run "engine run on". Great. The paperworks says this may happen on older cars with external regulator and to install the diode inline. I did that but it did not fix my problem. Not sure what to do now. I have battery and MSD unplugged till I get more time on it.
A typical cause of engine run on is the idle rpm is set too high. A stock 350 should idle around 6-700 rpms I would think.
Hmmm... Did some adjusting to the carb to hold me over till I get my QJet. Replaced the manual choke with electric also. Good thing is I reached in window and car starts right up even sitting for 24hrs. I'll try adjusting rpm down, I'm guessing it's a bit high. ---------- Post added at 05:12 PM ---------- Previous post was at 05:05 PM ---------- Alright, that would have been too easy. Adjusted RPM and same problem. New at this stuff so I am hoping you wasn't pulling my leg. Pretty sure it's electrical. Worth a try tho. Thanks. ---------- Post added at 05:21 PM ---------- Previous post was at 05:12 PM ---------- Instructions on the MSD ignition module says you can have engine run on when installed with the external regulator. Add a diode inline with alternator to correct problem. It also says to put it on the smaller of the 2 wires to the harness. They look the same so I added to the one that may be the smaller of the two. Didn't solve problem. Guess I can install it on the other wire and see if that does it. Just installed a 1-wire alternator (hoping the internal regulator would do it) and left the harness out which I believe should be basically disconnecting the external regulator. But tried it and even with a one wire alt, still will not turn off with the key. Btw, I just unplug the MSD unit to kill the car. ---------- Post added at 05:40 PM ---------- Previous post was at 05:21 PM ---------- Something else i have nothiced is the Gen light stays on and radio componets. So i have power to the ignition switch, even when key is off. Could this be a ignition switch problem? Didn't mean for so many post here, just trying give all information I see. Maybe find the silver bullet to fix the beast.
The small red wire that goes to the ignition box, should be connected to the ignition switch lead. On a points system, this would be the wire that was originally on the + side of the coil. In any case, that wire should have 12 volts when the ignition is on, and 0 volts when the ignition is off. You can easily verify this with a meter or test light. All that wire does is turn the box on and off. Another thing to clarify is exactly what are we talking about when you refer to engine run on? There is a difference between "the engine continues to run when I shut the key", and the "engine continues to turn or diesel" after I shut it down. The diode is directional. It must be installed with the correct direction. A diode allows electrical flow in one direction, but blocks it in the other. What you are doing is installing the diode in the lead to the GEN light. That wire back feeds to keep the box on, and the engine continues to run. The diode prevents the back feed. Make sure you have the diode installed with the correct direction, and in the correct wire.
It will probably be this weekend to work on the beast again. Larry I'll check with voltmeter ... But may have it figured out. Well actually I think Mark may have figured it out for me (Thanks!!) The problem I am having is what I believe you call engine run on. To be clear, just in case this helps someone else someday, the engine continues to run just as if you never turned it off. Doesn't sputter and "diesel", it just keeps running strong. Actually sounds pretty good :grin: . I have checked and rechecked the wires on MSD controller and blaster 2. All looks perfect with good contacts. What I've tried: Installed diode in correct direction (I think) inline with alternator harness. Didn't help. Reinstalled diode the reverse direction just in case I was wrong on direction. Didn't help, engine keeps running after keys in my hand. Disconnected the electric choke on carb that I installed over weekend. Just on chance I was getting electric back from the power wire. Didn't fix problem. Disconnected harness on alternator and power cord, basically removed alternator. Still same problem, so alternator is not sending the problem. Also tells me it's not anything do with electric feedback from regulator, so probably not an MSD problem. Called MSD and they confirmed, it's not the MSD control module, but suggested a "short" somewhere else in the electrical system. Ohhh boy, what did I do...what did I fry!?? Then Mark (carmantx) said something that makes perfect sense and probably what's wrong. When I installed the new battery cables the problem started. I assumed it was because I was getting improved electric flow. The positive cable goes from battery to starter solenoid and is a pain in the butt to reach because the headers are in the way. I have tried verify this, but just can't get a clear view BUT... I am almost sure I have contacted both starter solenoid terminals with the new cable when I torqued the nut. I'll confirm this is the issue when I can really dig into it this weekend. May go ahead with a mini starter swap this weekend, depending on if I can get the starter out without removing headers. Thanks again guys! What a great group on here.
Well, I got some time to work a bit on the Buick and problem fixed! I did make contact across the solenoid.
