Hi Silver-911,
Sounds like you have a really nice car, making some suggestions for you to start with, others will chime in soon...
Quote:
Originally Posted by Silver-911
But the engine is a 1980 911SC powertrain.
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As a starting point, it might be a good idea to check the engine type stamped on the engine (for example 930/09), the location can be seen in this post
http://forums.pelicanparts.com/porsche-911-technical-forum/988587-911-sc-engine.html#post9939070. The engine type number can help indicate if the engine is originally ROW or USA specification...
You can find out more info here:
Simon's Porsche 911 SC Site
Quote:
Originally Posted by Silver-911
However, it appears to be missing a few components, specifically the decel valve and the thermo time valve.
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Depending on what your engine type is, one option is to look through either the ROW or USA PET to see what components may be missing.
If you haven't got the PET yet, you can download the ROW PET from here:
https://www.porsche.com/international/accessoriesandservice/classic/genuineparts/originalpartscatalogue/
and the USA one from here:
https://www.porsche.com/usa/accessoriesandservices/classic/genuineparts/originalpartscatalogue/
Quote:
Originally Posted by Silver-911
Currently the vacuum system is connected like this:
Upper vacuum on back of throttle body (facing front of car) goes to the lower port on the distributor. The front vacuum port of the throttle body is going to the upper port on the distributor.
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It sounds like you have a 911SC distributor with two vacuum unit ports installed in your car, it is used on engine types 930.07/08/16/17 according to the USA_911_78-83 PET.
It is my understanding that the vacuum unit on distributors for 911SC ROW engines only have one port for vacuum advance... There may be exceptions of course, so others can correct me if I am wrong... The distributor for the 81' 930/10 engine in my car has one port for vacuum advance.
Quote:
Originally Posted by Silver-911
The car does run a bit lumpy when cold though, so the thermo time valve before the WUR would probably fix that. I could try pulling the vacuum line off the WUR while the car warms up and see if it runs smoother until it warms up.
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Pulling the vacuum line off the 089 WUR (temporarily to test only) should lower the control pressure and change the AFR (assuming that the 089 WUR is functioning correctly), whether it smooths out the engine or not depends on how the mixture is set.
Posting some pictures of the engine bay and the CIS will also help....
