A couple of weeks ago the car was running fine. I let it set for three weeks and tried to start it up and it would crank but the ignition would not fire.
I charged up the battery, tried it again the next evening and noticed that the MSD box (Streetfire) would lite up twice then nothing after a few seconds of cranking. I thought this was too low of voltage (MSD says below 9v) so I went through the Crank and Run circuits cleaning up any loose connections or just too many connections from over the years. After cleaning up the wiring I had the 2 year old battery checked at my local NAPA and it tested good.
I then cranked over the engine and noticed the MSD box would lite up once and then no more after a few seconds of cranking. So I removed the coil wire from the dist and grounded it out. Cranked the engine and noticed one spark then no more.


These are the voltages with a fresh charge on the battery:
- 12.5v bat
- 12.5v bat feed to MSD (large red)
- 12.2v at alt
- 11.2v at small MSD red wire (RUN)
- 10.6v at small MSD wire (CRANKING)
- Coil (MSD Vibration) wire sparks once on grounded screwdriver
- MSD box fires one RED led then nothing after continued crank

Does this point to the MSD box? Or is this the dist pickup not triggering the MSD box?
If not these, then what do you suggest?

Thank you!!

Just checked the resistance on the dist pickup and read 0.00 three times just to make sure.

Thanks!

Had that problem once. Ran fine, then one day no start. I don't recall the test I did, but it was in my MSD paperwork. The box had gone bad after 20+ years.
The problem was mounting the Blaster2 coil horizontally, which didn't allow the oil inside to completely cool it. Eventually this became a feedback-kind of issue that killed the box.
Sent the box to TechWest back east, and they fixed it for about $90 including shipping, and turned me on to the cause & using an F-150 epoxy coil instead. Car would light off almost instantly after that.

('90-ish F-150 302 V8 coil, uses a pigtail terminal, both from auto-parts house for under $50, fabbed bracket from short length of aluminum angle stock & 2 fasteners)

Sounds like your MSD box is still making a spark. Here's the manufacturer's suggested testing method:
https://www.holley.com/support/troubleshooting_techniques/

I once replaced a pickup coil but found out later the coil was good, corrosion had formed in the connector.

I've had two instances of no spark or intermittent spark caused by a poorly grounded coil.

R.

Thanks to both of you!

Tonight I went out and tested my ground connection from the Large Black wire to the battery to find a questionable connector so it got replaced. Then I removed the cable that goes from the distributor to the MSD box and found a little bit of corrosion starting so it got cleaned up. I then retested the coil wire to ground for spark and only found one spark during a 5 second or so crank test. The MSD box did blink 4 times during that test.

Next I will replace the coil with another one on my shelf to see if that makes a difference.
I just printed out the MSD test and I will try it too.

Thanks again!

I tested the MSD box per the above instructions (which removes the magnetic pickup out of the equation) and the MSD box lit up and a spark came out of the coil wire. This is good but then it points to the dist.
So I removed the dist cap and checked the gap, but when I grabbed the pickup, it wiggled side to side and then I was able to pull up on the plate about a 1/2". It was pivoting on one of the hold down pins and I assume by this movement that the other one broke. There is no way that plate was staying stationary to keep the spark accurate and it was moving far away from the star wheel.

So it appears that I need to start researching new distributors.

Thanks again!