Hello all, I am completely new to the Buick world. I got my hands on a BEAUTIFUL 1970 Skylark GSX clone and I’ve got to track down a random stalling issue with it... I think it “may” be the coil at this point. At first I thought I may have an issue with vapor lock but I’m leaning toward ignition. This has happened to me on two occasions now. The car drives great for a decent length of time, water temp never goes above 180, never shows signs of imminent stall like sputtering, bogging or anything like that. Then, out of nowhere, boom, dead. I’ve driven the car over an hour before with no issues at all, then the first time this happened was about 30 minutes into a city road cruise, stop and go but the outside weather was about 60 degrees. I have an aftermarket water temp gauge and I watch it like a hawk. Both times the water temp was 170ish... When the car stalls, I wait a few minutes, fire it back up and drive it home with no problem. The car has the factory mechanical fuel pump with 1/4 vapor return line installed. I threw a vented gas cap on it after the first stall just as a bandaid to see if I had a suction issue, but then the second stall occurred and I threw that idea out the window. The first time it happened, I was cruising around not beating on it by any means and when I was accelerating through maybe 30mph it just died. Then, the second occasion I had driven it about an hour in 50 degree weather, highway, city streets, no problems. Then, I’m going down my street toward my house, downshifted from third to second gear and bam. Died on me again. Frustrated is the tame way of explaining how I felt haha. This time, I noticed some gray smoke come out through the hood’s intake vents.... To be as descriptive as possible, I bought the car with a MSD6AL control box attached to the factory distributor by means of an aftermarket coil. I’ve read the MSD box either works or doesn’t and usually doesn’t “die” randomly like that. The car was VERY WELL restored and the engine compartment is near immaculate. I did some other research and it has the correct low resistance wires from the distributor to the plugs. I have not had the chance to look for a resistance wire but given the meticulous way the car was completed, the person who rebuilt the engine knew what they were doing and I assume (dangerous, I know) that they were aware of and bypassed the resistance wire appropriately. At this point, I think the ignition coil may be overheating? Any thoughts? Thanks for any response. I know this is a lengthy post but I wanted to be as descriptive about the issue as possible. Respectfully; Josh P.
Josh, it sure does sound like ignition if it stalls that suddenly at speed. I would check all the wiring connections for corrosion, looseness, and fraying. If you are using points to trigger the MSD box, then the original coil + wire is connected to the small red wire of the MSD box. The resistor wire would be inline with that coil + wire, and all it does is turn the box on and off with the ignition switch. You might want to check to see if that lead indeed still has the resistance wire present. If it does, you might want to eliminate it so the box turn on gets a full 12 volts. It probably isn't the problem, but it might be. The box gets its main power right from the battery, so check the big 10 gauge red and black wires. I have mine wired right to the battery. The box supplies the coil directly with the small black (-) and orange (+)wires. The box gets the trigger from the original coil - wire from the distributor. That wire would be connected to the white wire from the box. The points should last forever because all they do is trigger the box, which takes very little current. Again, I would look at all your connections, might just be a loose or bad connection. One other thing to check would be the underside of the distributor cap. I have seen MSD ignitions eat the small center button of the cap, even melting the cap a bit. Easy to check. BTW, looks like a nice car, enjoy.
Thank you very much for the info! I’ll be sure to check it all and see if anything stands out. I really appreciate it
Is that "aftermarket coil" compatible with your ignition system? Not all are. Some systems list which coils will and won't work with them. If you can borrow a coil that is known to be good and compatible, you could install it and see if it cures your problem. At least then you'd know for sure that your problem is coil-related. Also--I have never run an MSD, but the instructions that came with my Moroso points eliminating system say "Do NOT use copper core spark plug wires." So you may wanna look into that.
