Triumph Repair: no spark from coil, power resistor, air gap

Question
Hi Howard. I have a 1977 spitfire that lost spark. Last summer we would be driving along and car would quit like turning off a switch. Turning it over would cause it to backfire.Then out of the blue it would start and run fine. Last week we put the car on the road was running fine. Next day wife went to go for a drive,got car running,backed out of driveway and car died. Haven,t been able to start it since. car came with a firebll xr700 that hasn,t been installed. Any  info to my problem would be greatly appreciated! Thank's for your time!

Answer
Hi John,

If you still have the "Opus/Lucas" electronic ignition (unusual because of their high failure rate) all you can do is check the air gap (.015") and confirm power to the coil through the resistor wire with the key "On" and a full 12v to the coil in the "start" position and power to the power resistor for the control unit (mounted on the distributor)

You must do all testing while it is in a failed mode.

Sorry, I don't know anything about your "fireball xr700" unit. However, when the Lucas system fails you could try installing the aftermarket system (if it came with instructions)to see if it corrects the problem.

Electronic ignition is fine when it is working but out on a road at night if you had the engineer who designed it in the passenger's seat when it dies, he can't fix it.

Howard