maze

Hi Folks,
My project is a 69 911E w/MFI.
The cold start solenoid is not firing when cold, and Im not getting voltage to it. When I jump 12v to it directly it works great....gas everywhere.

I have traced the wiring back to the Thermal Time Switch on the manifold. It shows an open circuit to ground on the red/blk wire at ambient temp (70F).

This switch has a part number 901.617.117.00 and is marked -10C. That seems very cold from what I have read for a tts.

There are two such switches adjacent on the manifold and the other switch closer to the rear of the car, is stamped 35C. The schematic shows this to be a Temperature switch (start)...not sure what it does. Its part number starts with 911.617.11X.XX (last digits are destroyed)

I have another TTS from a parts pile that has the following numbers 911.617.117.00 and is stamped +45C.

My big question is can I use the 45C part in place of the -10C part without screwing up the works?

Second question is can someone confirm the -10C part is correct for this car and why such a low temperature switch?

By the way the car is very hard to start without a gas dump down the throut (the cars...not mine!)

Thanks
maze