I’ve had this problem intermittently but up until today it’s gone away within a few tries.
The car is a 1984 242 DL with a B19K, Solex carb and an M45 transmission.

In short it starts after 1-2 seconds of cranking and will keep running as long as the key is in the start / III position but as soon as I turn it back to the running / II position it loses all spark.

I tried jumping the ignition coil input to the battery but no cigar.

What do you think is the problem and how to fix.
I am currently stranded on the side of the road so help will be appreciated.

 

I checked with multimeter that the ignition coil gets power when cranking but when turning back to the II position it does not.

 

The alternator light also turns on when it is running with the key in the III position but I do not know if it’s supposed to be line that.

 

The alternator light was caused by an unshielded wire it seems. I mowed one of the alternator wire and now it is charging again

 

Ok so, got it towed home and with a little help from an automotive electrical book from the library I got it running by jumping the positive side of the ignition coil. Works fine now but I just need to remember to disconnect the battery to shut off the engine.

I phoned a friend to ask what could be the underlying cause of this problem and I got 2 possible causes from him. Those being the ignition switch / key barrel electricals or the whole of the wiring harness itself.

I certainly hope it’s the key barrel but I would not be surprised if it is the harness as I’ve had to bypass it in a few places over the years.

I’m in no way a trained mechanic and have very little experience on the electrical side of things so what would be the best course of action right now?

 

I suspect bad ignition switch. You are effectively bypassing it by jumping the positive side of the coil to battery positive. Do all the other features work with the key in position II (wipers, radio, etc....)

 

Yes. Everything else works flawlessly. Lights, wipers, radio, rear glass heating. All of that works.