Thermovalve in CIS system???

I've been looking at the vacuum schematic for the 74-83 CIS system. Between the vacuum limiter and the warm up regulator there is a device called a thermovalve. Can anybody tell me what this thing is supposed to do, and how I can test whether or not it is doing it?

Thanks



------------------
Bill Krause
'79 911SC Euro

Methinks that is the vacuum valve that controls the vacuum to the warmup regulator. It is open when cold, so on a cold start, it allows vacuum to the "vacuum controlled" warmup regulator for initial enrichment. It has an electrical heating element that warms with the ignition on. After about 30 seconds, it has warmed up and closes off the vacuum to the WUR. The WUR continues to warm itself up through its own electrical heater as the engine goes through its warmup period.

Thanks, that makes sense. My WUR has two vacuum hoses attached to it. One that goes directly to the throttle body, and one that passes through that thermovalve thing. My Bosch book has a picture of a similar WUR, but doesn't explain why there are two vacuum inputs, and doesn't describe any vacuum induced enrichment during warm up. I think I'll pinch off the one from the thermovalve and see if it makes a difference when starting cold.

------------------
Bill Krause
'79 911SC Euro

The vacuum line thru the thermovalve should go into the bottom of the WUR. During the 30 seconds that it operates, it richens the mixture only during the very early period after startup. That's 30 second MAX at very cold temperatures. Up around 60 or so degrees, the thermovalve is closed BEFORE starting, so there it no initial enrichment.

The other vacuum line operates to lean the mixture at high vacuum (throttle closed) and richen the mixture at low vacuum (throttle open). Thus "vacuum-controlled WUR".

The two vacuum lines work against each other. The one that goes thru the thermovalve operates over a larger area and overpowers the line that comes in the top of the WUR. But it only operates for <=30 seconds.

Thanks, that was a great description.

------------------
Bill Krause
'79 911SC Euro

I have been reading with great interest the replies SeaDweller has been getting in regards to his CIS issues, for I have similiar symptoms. However, armed with The Haynes as well as the Bentley manuals, and the maintainance manuals on Fiche, I seem to be getting more confused than anything, but still trying to learn.

In any event, I have a 86 930, and just to the lower left side of the intercooler, is what I believe is this Thermo Valve. It's got the two electrical wires to it, the vacumn line from the distributor, one to what I believe is the trottle body, but there is a third line on the front side, that that is about 3 inches long, makes a 180 degree turn back to rear, and is attached to nothing. Me thinks something is not right.

Is this device what I think it is, and is the plumbing correct ? Obviously my experience and familiarity with this car is quite low, but we will get there !

Can you identify the item in any of the parts diagrams on the pelicanparts.com website? I'm not familiar with the turbo systems.

------------------
Bill Krause
'79 911SC Euro

BILL:

I've gone through all the diagrams on the Pelican site, and there isnot one that exactly matches. I did take the liberty of e-mailing you a couple shots of the part I'm talking about. There appears to be a part number stamped on the side, that being
911 618 123 00

Thanks !

That part no. is for a '86-'89 turbo, and is called a "Ignition Retard Valve". I can't tell you anymore than that. The parts diagram that I have sort of shows it connected to the throttle body, and to the distributor, and a third connection going off page. Maybe some of the turbo owners could help you out more.



------------------
Bill Krause
'79 911SC Euro