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1977 280SE CIS Vacuum line hookup - FIXED

Started by tinker, 29 July 2005, 11:47 PM


I just got this car and it always dies on sudden deceleration. I am going through everything in the service manual and have hit a snag. It concerns the hook up of the vacuum line from the distributor advance to the throttle valve on the CIS. The problem is there are two connections right next each other.

In the 1977 diagrams it shows the advance hooked to the top one and the charcoal canister hooked to the bottom.  But in a picture is clearly show that the advance is hooked to the bottom. To add to this confusion the 1978 diagrams also shows the advance hooked to the bottom.

So does anyone know which way its supposed to be?
I have the California with Catalyst version.


Well I managed to sort out all the problems. She is running great now. It turns out that the lower connection on the throttle valve was plugged with gunk. Once it was unplugged with compressed air there was little difference between the vacuum readings so I hooked up the advance to the top one.