How do I set the throttle valve on early 944?
 

New to us, 1985.1 944 N/A with 62,000 miles. Replaced:spark plugs, plug wires, cap & rotor, engine temp sensor, both crankshaft sensors, 3 fuel injectors, fuel filter, oil and filter, air filter, all belts, adjusters and rollers and some other items not related to how the engine runs.

And it runs great! Starts right up even in our current single digit temperatures. And it runs and drives very smoothly. However,

1. when it first starts in the bitter cold, it runs rough until it warms up (a few minutes)
2. when fully warmed up, it idles high (1400 rpm)

Investigation to date:

• I do not hear the idle switch click but I do hear the WOT switch. I will verify with a resistance check this evening.
• There is some slack in the throttle cable at idle
• It appears that a PO adjusted the throttle valve stop (the paint over the screw and nut is gone)
• I can press the throttle cam against the stop and achieve a lower idle speed

Theory:
To compensate for poor maintenance of the fuel system causing low idle, the PO used the throttle stop adjustment to increase the idle. (the factory seal still covers the real idle adjustment screw) That resulted in preventing the throttle from triggering the idle switch. Which, in turn, causes rough idle when cold and high idle when warm.

Problem:
I would like to verify that the throttle valve stop is set correctly. But I have searched everywhere and cannot find instructions on how to do that. Any pelicans able to enlighten me?

SmileWavy

throttle stop should have a screwdriver slot and a 7 or 8mm locknut , loosen nut, turn stud counterclockwise (loosen) which will allow the blade to close more, you *should* hear the TPS click at some point if the clicker is still good.

lock the nut down.

then fine-tune the idle speed using the little bypass screw that stands on the side of the throttle body, i think it's 7 or 8mm as well, until idle speed is 950 +/- 50 rpm warm.
clockwise (tighten) lowers the idle speed, counterclockwise (loosen) will raise the idle speed.

Thank you. That is what I needed to know. And that solved my high idle issue. We shall see about the cold start tomorrow.