Hey all, it's been a while since I last posted here, but that should change since I started messing with the car again after quite a number of years.

Background/story:
The car has been sitting at my father-in-laws place for the past 15 years since we moved from the east coast to the west coast, and I only started it and moved it around his property a few times. For example: we would start it every couple of years, it used to be that we would start it and move it at least a few times a year until it started having cooling issues about 5 years ago, then it moved to a 1 every couple of years. Well my son turned 16, and he wants a project car and wants to get it back to the track, so I took some time off work last week and we took the drive out to get the car and bring it home this weekend.

The battery in the car was replaced in 2020 (foreshadowing here), and when we told my father-in-law we were going to get the car he made sure to put it on a charger. The car started first try, which is good considering it was ~15 months since we last started it or moved it around. We backed it out of his shop and I flipped on the water pump and cooling fans, but within about 5 minutes it started acting like it was low on fuel and stalled, slower idle, sputtering, and then stalled. Not trusting the fuel gauge that showed 1/2 full, I threw 5 gallons of fuel we brought with us in the tank and then attempted to restart it, battery was dead and just got 2 relay clicks before totally nothing (no fuel pump priming or anything). The battery voltage was down to 11something volts, so we knew the battery was on it's last legs, I then remembered that we unhooked the alternator the last time we ran the car (during New years 2025 trip to my father-in-law's about 15 months ago), so the car was running off the battery only for those 5 minutes including the e-water pump and both fans on high. We hooked the alternator back up, then jumped started the car, and it started and ran fine for about another 5 minutes, and even allowed us to move it around and get it onto the trailer. As it was sitting there running on the trailer my 16 year old wanted to see how the 2-step worked, so I flipped on the 2-step and got out and he was climbing in then the car stalled again same as before started acting like it was out of fuel, slowly stumbling then cutting out. The battery was too low to restart it, so we attempted to jump start it again, no luck, it wouldn't start at all. We thought, at least it's on the trailer and we'll figure out why it won't start when we get it back home since we were on a rushed timeline.

When we got it home, we tried jumping the battery again and even tried a new battery and it still wouldn't start. We originally assumed bad fuel or clogged fuel filter since it sat for so long and we assumed we ran it out of fuel. We smelled fuel after attempting to start it, but to rule that out we tried spraying starter fluid and that didn't change the symptoms. We moved on to check spark, and low and behold, there was no spark at the plugs, so I was thinking the leaking water pump (yes, that cooling issue referenced earlier) killed the Opti, but to rule that out I checked for spark at the output of the coil, and still no spark there. This is the only part I am second guessing, my son said the light was on on the MSD box, but I never confirmed it with my own eyes. So, I probed the signal wire from the original harness to the MSD harness and it looked good, but decided to unplug the wires going to the MSD and plug it them directly into the coil, and the car fired up on first crank. We got it off the trailer and into the garage, well actually moved it around a hand full of times and no issues with the MSD bypassed. Today, after some troubleshooting research on the MSD box I figured I would go out and try some of those troubleshooting tests on it, but when I plugged it back in, the status light for the MSD was no on, I verified all wiring and there is the voltage going into the box is good, but no lights on, and hence a no start condition or the ability to do any other testing.

Questions:
Could running the old battery out of power and dropping below 12v (maybe a couple times), burn out my MSD Digital 6 Plus?
Or what else could have happened?

That box has been on the car and many trips down the track for about 3 years, before it was sitting for 15 years, so there wasn't a ton of hours/miles on the box, or anything like that.
The only thing I can think happened, other than shear age, was it didn't like the voltage drop not only to the main wiring running to the battery, but 12v ignition on source as well when running. Also I think me arming the 2-step and not even revving it up is coincidence to it dying shortly after arming it, but included that detail in case others found the 2-step function to cause issues in the past, or in case my son hit the brake pedal when climbing it around the cage and happened to actually activate ( it as it died.

Wiring configuration:
MSD Digital 6 Plus (PN: 6520) hooked to the factory coil/plug via the MSD GM dual connector coil harness (PN: 8876), the main +/- run directly to the battery, and the blue accessory running to a relayed switch and break pedal switch (meaning: I have to arm it with a switch on the dash, then with it armed it only hits the 2-step limiter only when the brake pedal is pressed, so when I am staged I am just on throttle and brake and don't have to worry about anything else but lifting off the brake to launch).

 

I’ll give the same pitch I have to give to all the “old timers” coming back - this site is dead. Might get a few posts in a week, including spammers. There are maybe a half-dozen LT1 enthusiasts who show up from time-to- time to offer help. But even those members are not here as often as they used to be.

I’ve been here for 27+ years, and I try to check in every day. I can still cover a lot of the LT1 issues, but have no experience with the MSD Digital 6.

Sold my Formula 4 years ago. So I can’t go out and look at my car for inspiration. I am a bit fortunate in that the new owner made a couple updates, ran it on a 225-shot, and managed a 9.64 @ 139.4 MPH, on a 1.268 60-ft.

 

Hey Fred, thanks for the heads up. I looked around today and saw the same thing, nowhere near as active as it was back in the day. I also notice that my signature is so old that a few of the link are businesses gone by the way side, including friends that have passed away years ago.

 

You might find a “MSD Digital 6” related thread with a “search”, but then the links to photos, vendors, or tech references might all be dead.