what is this and is it needed

[wckrause]

Yep, I was wrong. On later SC's there is a seperate decel valve, and aux air valve. They just look very similar.

I will no longer comment on any CIS configuration other than my own ('79 Euro).

S-man. Admit it, you like the sound of the popping on decel.

[retnug]

" Yep, I was wrong. On later SC's there is a seperate decel valve, and aux air valve. They just look very similar.

I will no longer comment on any CIS configuration other than my own ('79 Euro). "


wckrause,

It is so hard to keep everything straight when Porsche changes things. The different (after market) manuals don't have all the permutations of the cars. They only put in the manual the specifics for the car that they used as the test subject. I can't speak for the Porsche manuals as I can't afford them at this point. A manual may have everything correct for part of the "run" of production but not for the next "run" of cars.

[stlrj]

Richard,

On a 3.2, the job of the decelleration valve is done electronically by way of the idle switch, idle air control valve (IAC), and the DME.

With your foot off the throttle on decelleration, the idle contact is closed, the DME shuts off the injectors until the rpm gets down to 1100 to eliminate the formation of unburned hydrocarbons and popping. Below 1100 rpm the injectors come on and the idle air control valve should throttle down to idle.

Joe

[wckrause]

The different (after market) manuals don't have all the permutations of the cars.

Tell me about it. Try to find a description of the operation of a thermovalve in any manual! Only the Haynes manual even shows one in a vacuum diagram. That's the only thing I dislike about CIS.

[Superman]

Okay okay. I admit it. I like the engine popping. Plus, like Gunter I am a little trepidatious about mashing a spendy Porsche part.

As far as the accuracy of your advice goes, Bill, I learn nearly as much from your guesses as from your certain knowledge. If anyone should quit guessing, it should be myself. As you know.

[retnug]

Superman,

I got over the trepidation and did the fix. I figure if you are going to leave the vacuum line unhooked or block the vacuum hose anyway, rendering the part unused, you may want to try the "fix".

[radcon]

Not to make this thread drag on forever, but I've got one more question. Could someone with an '80 SC please send me a pic of the right side of their engine showing the Aux air valve, Aux air regulator and decel valve. Which one is supposed to have the small vacuum line attached to it on the outboard side? The pancake that is toward the front of the car or the one closer to the rear of the car. I think the PO may have had this hooked up incorrectly the whole time, since both of mine have a port on the outboard side for a vacuum line. Want to confirm this with someone else who has an '80, since all the other years seem to be different. Thanks.

[BrokeMyCar]

Anyone else tried the "pinch the decel valve" method? Any feel for how much pinch? I think I might try, as soon as I figure out how to replace that vacuum line (anyone got a pic of an 81-83 SC engine from behind??).

Babak

PS gotta love bumping the old threads