part identification

Minardi · 01-08-2005, 10:21 AM

I am a new Porsche (a trodden down 1978SC) owner and this is my first post.

I just completed a valve adjustment, installed new spark plug cables, spark plugs, and rebuilt distributor. In putting my car back together I noticed a component with a wire that had come unattached. I searched through my manuals to identify what this component is but I wasn't able to find anything.

Could someone kindly look at the attached photo and let me know what the component is?

Also, were it to remain in its current state (i.e., unattached) what affect would this have?

Many thanks. I sincerely appreciate the help and all of the information I have gotten from this site since purchasing my first Porsche 4 months ago.

Minardi
1978SC -- Tucson, AZ

3.2 CAB · 01-09-2005, 05:02 AM

I'll take a shot at it, looks like it might be part# 911 613 131 00 which is a vacuum operated microswitch. I don't really have a clue as to just what its function is, but with one wire out of it, it certainly can't work. I would reattach the loose wire and see what it does.

3.2 CAB · 01-09-2005, 05:21 AM

I just found a wiring diagram on the SC, if it is that part, it is part of the O2 sensor system.

Minardi · 01-09-2005, 07:18 AM

Many thanks. Will look into this further and report back. My SC is a '78 and I didn't think it had an O2 sensor system.

I did get the wire re-attached and the car seems to be running fine....for now.
__________
'78 911 SC

PeterTarga · 01-09-2005, 07:51 AM

Hi,

It's a thermo valve see also here http://www.pelicanparts.com/catalog/images/fuel_injection/new_images/fi_fielsystem_1-7-2d17a.jpg.
I don't know the function of this valve and could't find it, can someone explain it ?

Regards,

Peter

Minardi · 01-09-2005, 06:21 PM

Peter,

Thanks for the information...that is in fact the part. I asked what it does and was told that it provides an enriched mixture during startup. Frankly, I thought that the WUR took care of all of this but apparently not.

ciao,

Christian

------
'78 SC -- Tucson

Minardi · 01-22-2005, 02:39 PM

The below came from

http://members.rennlist.com/jimwms/CIS/CIShome.html

thought it did a really good job of describing what a thermo valve does...
-----------------------------------------------
Holds off vacuum from the warm-up regulator when engine is started cold ('77 - '79 engines). Power is applied to the thermal valve when engine is started, and approximately 30 seconds later, the valve opens. When the valve is open, vacuum to the WUR is then determined by the intake manifold. --The vacuum holdoff results in a mixture richening at warmup. The inner hose connects to the intake vacuum source and the outer hose to the WUR.

Failure mode: An open circuit in the internal heater will keep the mixture from properly leaning out as the engine wams.

ciao, Christian