1973 911 Need Emergancy Blinkers On To Run

[1973911tes]

This problem is intermitant and last nite it came back again ,this is what happens ,my 1971 911 mfi all rebuilt and runing perfect ,would not run over 1500 rpm ,when it did it would cut out and then huge backfires out the ex pipe. This has happened 3 times since I put the motor back in the car ,in the past if shut the car off it would go away but last nite when it did it I could not pull over right away so I put on the emergancy blinkers and lo and behold when the flashers would flash the motod would run ,when the flashers were off it would die ,if I kepl the rpm's under 1500 it woull be fine but as soon as the rpm's got up it would start. I am thinking a ground problem any help in this would be great ,one oputher thing the tac has not worked since the motor went back in ,I tested the lead wire from the dist. and it is fine ,I dont know if they are related .thanks
DAVID

[dtw]

Wow. That's the weirdest thing I've heard yet- a few suggestions:
-Check electricals carefully for Lucas components, discard and replace with Bosch components.
-Consider scheduling an exorcism.

Sorry to make jokes. Sounds like a tough problem. As far as the tach, have you tested the signal at the tach? I found I had a good signal when the same happened to me...the tach got tossed in favor of a good working unit.

[pwd72s]

I'd definitely suggest checking your fuse panels...all of them, for any corrosion, bad connections, etc.

[rickeolis]

Electricians call this effect a ghost ground. (Or floating ground)

It's when the real ground is too weak to be effective and the electricity hunts for the best ground it can find, even if it finds it in another circuit.

I would indeed look to see that your ground strap under the engine is intact, and that all of the other stock grounding points are good. Good luck-

[1973911tes]

THANKS FOR THE EARLY HELP ,all the main grounds are good ,eather new or just cleaned ,I am thinking the ground going in to the cdi unit I did not like the way the 3 wire plug felt when I put it on I will fool with it in the am ,need to go to work for the rest of the day.

[dtw]

You're going to need to tell me your secrets for your muffler, shroud, intake stacks, oil cooler, heat exchangers, etc. Everything looks new, how did you do it?? (OMG all that stuff isn't new is it??).

Excellent detail work, hope you get your problems sorted out soon.

[1973911tes]

the shrouds I just painted but all the rest is new .I got the car for short money and went to town rebuilding it ,heads ported to E specs, S pistons E cams ,and all the mfi stuff rebuilt to e specs . when it runs it runs great .

[AZ1977911]

Beautiful motor!!!

Dirty points can cause this behaviour. Dont ask ;-}