Hey guys!!

Posting here after a year...had bought a '79 911 SC and kept the '68 for a weekender..ill admit it but...im starting to get pangs where I just forget the 911 and jump straight in the FB...lol...

During these 'pangs' I discovered a strange issue;

While driving, the car automatically shuts off..its as though someone switched it off...the fuel pump is fine..checked that..sparks are fine...I think its solely an electrical failure of some sort...because im driving along fine and then all of a sudden..it seems as though the power is draining and WHOOM it just shuts off...the only thing that is on is the ALT light in the tacho...I checked all the connections to the alt, couldnt find anything...

PLEASE HELP!!!!!

 

Will it start back up after it dies? What about the wiring for the coil? the Primary and secondary circuits all tight and working fine? What about the coil its self is it good?

 

KB is on to something. It definitely sounds like an ignition circuit failure. Symptoms of a coil failure are usually that it starts fine when cold then suddenly stops running. It won't start immediately, but will once it cools down a little.

 

Yup..it starts afterwards...or if i chuck it in 2nd and pop the clutch...Ill recheck the connections and come back with an update...is there anyway of knowing if the coil is stuffed?

 

Yes, I forget how exactly to check the coil with a multimeter, however coils are usually oil filled and if you disconnect and shake it you should be able to hear the oil slosh around in it. Shaking it only tells you if you have oil in the coil or not (no oil would take away the cooling ability and cause the coil to not work), its no guarantee to determining that its working fine. What about the Dizy? what does it look like? when was the last time you did any maintenance on it?

 

Heres the first thing that I would do. Any plact that their is a connection (engine harness connection, screw for ground, engine ground strap, key switch, battery terminals, etc) I would check all of those first. At least take then loose and clean them, and maybe apply some antioxident when you reconnect to slow the corrosion process. When you reconnect, make sure they are tight and the engine strap(s) are good. I normally use two just for insurance. You may hit the problem right away and in any event, this is something that needs to be done anyway. If you are unable to locate the problem by doing this, then look for the supply circuits or weak or failing parts. Corrosion is probably responsible for 90%of the electrical problems in these old rides.

 

A failing coil usually causes the carb to back fire. I suspect that you have a ground issue. Some circuit is going to ground through the vibration of driving. One way to check the coil is start the car up and in the dark use a spray bottle to apply a mist to the coil body. If its failing because its grounding out, you will see sparks form on the coil body. When a coil fails it allows a blow back through the carb. You may not be hearing this and when it occurs the car shuts off.

 

Thanks guys!!

I will do the above mentioned and let you know..might take a bit because I have some workload these days...

Thanks once again!

 

just on a sidenote:
I had the same issue with a pertronix distributor. The problem tehre was that the ground to the ignitor module was loose (straight from day 1). just in case you have one of them:
the ground for the module is on the screw that holds the vacuum canister at distributor in place. So if you can rattle (move) the canister then tighten that thing down.
I'm convinced (just like the others) that your problem is ignition. Either a cable that is not connected properly (as in on-off-on ...) or a bad coil