Part ID - What is this ? (3.2)

[911Atlanta]

All -- need some help identifying what this thing is and what does it do ?! (see photos below). It's front/center on my 3.2, and appears to be a small cylindrical female electronic plug fitting of some type. It has a black rubber plug (taken out on the second photo and sitting just above on top of the idle regulator).

As always, you help is appreciated.

Thanks, Dan

[rick-l]

The schematic says it is a "connection for test instrument"

Pin A goes to pin 12 of the DME.
Pin B to the "throttle valve switch"
Pin C is ground.

Pin 12 of the DME COULD be a serial stream going out but I don't what it would contain or how it is used.


Edit: I am sure with all the DME experts here if there was any usable info on the line to the test connector Pin A that goes to Pin 12 of the DME and the serial TXD pin of the 8051 we would know about it.

[yelcab1]

I used to know this, but my DME memory is bad now that I drive a CIS. I believe it is a connector that disables the DME compensating function while the idle mixture is adjusted at the factory. Once it is set, there is not much to do with that connector.

[IROC]

It's the TDC (Top Dead Center) test connection point. It's only use is diagnostic - it has nothing to do with the function of the engine.

Mike

[ChrisBennet]

It goes to an unused flywheel TDC sensor. It is not connected to the DME in any way. Supposedly it is for testing but I am not aware of a test regime that uses it. Just to be sure I just checked the factory "DME Test Plan" (WKD 490 921)and I didn't find it used anywhere.

-Chris

[911Atlanta]

Thanks gentlemen -- I knew this group would know exactly what it was !

Regards, Dan