TR6 Non-start diagnosis

[Crisis]

Good Morning Forum Members,
I am having trouble with my 73 TR6 and was hoping the forum could help me figure out what is wrong. Background: car started to accelerate badly and at first seemed to only be a problem from stop. Then, I was lucky to get it home as I could not build enough revs to give the car any power. I let the car sit for a while, check gas flow north of filter, check gas flow immediately before carbs (squirt into jar). Tested for spark at plugs (inline tester), cleaned plugs, tested compression (130-148 psi), had 12 volts at + side of coil. Car turned over freely and strongly. All seemed ok. Started car (this is a week later now) and took for test run. Ran beautifully and quite strongly up to my turnaround point. Started heading back to house (10 miles +-), car started to die, huge backfire from tailpipe and stopped. Got her towed home on a deck. Still have spark at plugs, still have fuel at carbs (pulled plugs at bottom of float bowl and a lot of gas dropped out), 12+ volts at coil. Turns over strongly but you can just feel that nothing is going to happen.
Any thoughts? Thank you.

 

[tdskip]

Have you checked the carb diaphragms by chance?

 

[Crisis]

Have not checked them, however, they are fairly new. And, car doesn't even catch a little bit now. Turns over strong but you can tell nothing is going to happen. I can check diaphragms tomorrow to be sure. Thanks!

 

[LarryK]

Ignition wires at coil and/or points?

 

[Marvin Gruber]

Check spark plugs. The ones now a days ever get wet they are trouble to work again. Sounds crazy but its happened to me a couple of times. Plugs are cheap, put another set in and see if that helps. Electronic ign or points?
marv

 

[Crisis]

Good spark going to the plugs. I use one of those inline plug testers with the window, and I can see a good spark going to each plug. Wouldn't that mean coil was getting power and then sending large volts to distributor, and then to plugs in turn?
My car has a Lumenition electronic ignition system. Small metal box screwed to bulkhead under wiper motor. Wires go to distributer in a small loom with multi wire connector. I suppose it could be malfunctioning? Don't know much about it but has worked infallibly for my 15 years of ownership. Spark is at plugs but I guess it could be in the completely wrong order? My "feeling" is it is electronic because of the huge tailpipe backfire when it quit, and the fact that it doesn't even catch a little bit when it turns over now.
Thanks Tdskip and Larry K.

 

[charleyf]

Try changing out the coil. When the coil gets hot ( after 10 miles) then it could be a problem. By the time you get the car home and start checking it out it is cool again and works fine. When my coil died one day I got the huge backfire. I decided that it was not giving any spark and then I would get a random spark when the whole exhaust system was full of unburned gas--BOOM.
Charley

 

[Marvin Gruber]

Big difference from spark at the plugs and spark across the plugs. Just because you have spark from wire to plug doesn't mean its going across electrode

marv

 

[Crisis]

Ah, thanks Marv. I'll swap them out tomorrow. Going to change out the coil as well, thanks Charley.

 

[JimmyBb]

I just had the same ssymtoms on a 72 TR6 except that it did not fail completely. I was always able to get home although sometimes 25 mph was a challenge. Turned out to be a problem with the float in the forward carb. It would shut down fuel flow sometimes