'78 911 SC won't start
 

Hello all,
Have a '78 SC. After having driven the car for a short period, turning it off and then trying to restart, no go. It was starting after a little coaxing.

On a road trip through the BC interior, (great roads, by the way), in 36C heat, stopped to fuel up after 200 kms or so, and wouldn't start. Had to have it towed to a VW dealership. Spark plugs were removed and in bad shape. They were replaced. Spark was checked on all plugs. All had spark, but not overly "hot". Car is getting fuel. Can smell it. Fuel pump relay was bypassed by PO. Car turns over, but does not want to fire. As the shop was going to close, the tech thought he would give it one more try. Car struggled, but started. Went a few hundred kms more. Turned the car off and same thing.

I hope I've given enough info to at least get things rolling. Stuck in the mountains, so it could be worse, but would like to get home.

is it running ok when once it starts? I would measure fuel pressure. Try known good coil.

The idle fluctuates, but once out on the highway, everything seems fine. Coil was brought up at VW. Never got around to trying another one. Thanks for the reply.

Most often this is due to a bad fuel accumulator, although it could be other things, incl a bad fuel pump check valve and an incorrect mixture, which could be caused by an out of spec WUR. A leaking cold start injector could also be at fault.

Since you are getting the hot start and idle fluctuation, after making sure all ignition components are in spec, I would check the fuel accumulator and the WUR. The WUR is checked w/ a fuel pressure gauge.

It sounds like your fuel mixture is too rich. Do you always get the idle fluctuation or only when hot? Check that your timing is not retarded, and that the mixture is correct.

Thank you Paul. Wishing I was home so there was a place that I could take it too, that had the right equipment and maybe a bit if a clue.

Sounds like accumulator.

I doubt spark is only bad when you try to restart it hot but is fine at other times.. either the accumulator or internal check valve in the fuel pump . Il go with accumulator.

Tech is saying "regulator", probably meaning accumulator. Smells like its just dumping fuel, as soon as the key is turned, flooding the engine. Going to let it sit and then try to get it going and get it the 400 kms home. Then take it to someone that knows what they're doing. Thank you to all that replied. I will try to remember to let you know the outcome.