what is this...

[aldente295]

Hi guys,

Preparing for my first engine drop, I'm to the step of unplugging the main wiring harness. While I was doing it, I noticed that the sensor in the photo below only had one wire connected to it.

I've looked through Bentley's but I can't find it. Can anyone identify it?

It clearly hasn't been working for awhile and I haven't missed it ... but then I am dropping my engine aren't I.

It's located in the back left of the engine, just next to the heater hose inlet on the tinware:






It also looks like I need to find some tougher gloves...

cheers
Al

[sc_rufctr]

Quote from our sponsors parts section....

Thermotime Switch on chain cover, 911 (1974-83), 911 Turbo (1976-85)

Timing Chain Temp Sensors
This sensor measures the temperature at the engine's timing chain cover on the left side. Interestingly enough, this switch also has positive current going to it, which makes it act as a small heating element as well. It only stays powered during cranking and the heating element signals it to stop sending power to the cold-start valve if the engine does not start after much cranking -- to avoid flooding the engine.

http://www.pelicanparts.com/cgi-bin/ksearch/PEL_search.cgi?command=show_part_page&please_wait=N&make=POR&model=911M&section=FULcis&page=8&bookmark=31&part_number=911-617-117-00-M100

[aldente295]

Aha! Thanks Peter. Yet another case of I don't know what I don't know. I have had a bit of a rough idle at cold - I wonder if this is the culprit? I won't know until I get the engine back in (tranny rebuild first) but... fingers crossed.

[tharbert]

This wouldn't affect your idle but it would affect starting. It's operation is limited to the period of time the starter is engaged. It allows the cold start switch to squirt gas into your intake for a relatively short period of time and only when the engine is within a certain temerature range.

Search for cold start switch and you will be rewarded with page upon page of discussion about this little gem.