Joe, I think you are well on your way to figuring this out thanks to David, Alfred and Pauls. I was intrigued by the mention of the Lucas AB14 ignition module and went looking for some information about it and found this…
https://tinyurl.com/ydbjnthr
Although the paper describes an ignition system used in a TR4A, what’s quite interesting is all the useful information along with the description of the AB14 ignition module about a third of the way through the paper. Particularly the thermal precautions you should follow now that you’re using it to drive a 0.6 Ohm coil in your ignition circuit. I can also see your reference to the GM HEI module in your original post which is used in the Lucas AB14 housing. I gleaned so much info from this article I thought others might like to read it.
Good luck
Anthony
Problem solved. Bad ignition switches! First, the Lucas switch failed, replaced with NAPA (Balkamp) switch which had an internal fault, cutting power to the ignition circuit when the starter circuit was engaged. Replaced with another NAPA switch and now the car starts and runs!
Thanks to all for your help.
Joe
great to hear, now go out and “drive it like you stole it”.
Alfred
Good troubleshooting Joe!!! Who would think there would be so many defective switches in a row!!
pauls
I never thought Id get THIRTEEN bad, brand new BMW 2002 t-stats in a row, either…
Me either!!! Dang!!!
Joe not sure what year you have but my '68 has the ignition switch on the column but does not lock the column. When my original switch fried several years ago I replaced it with Lucas p/n 34680. Seems much better and heavier than my original. It came with new keys but I was able to swap out the key tumbler and stay with my original keys that also work on the doors.
David
68 E-type FHC
Good work on the diagnosis Joe. Did you find a spare GM HEI Amplifier module at a reasonable price?
Joe,
Great news! Now back to enjoying the car…
Anthony,
Yes, several sources. Google Lucas AB14 and you will get a number of hits with prices as low as $10 for the replacement circuit module
Joe
Alfred, precisely the problem - combined with a bad ignition switch. Took a while to diagnose - finally went back to the original Lucas switch to map it’s connections. One of the switches left battery voltage on the ignition terminal with the switch in the off position. Thanks for the help.
Joe