Throttle Cable Screw

[joelittel]

Does anyone know the factory setting on the throttle cable screw?

[bradartigue]

For what? Carbureted or Fuel Injected? Base settings are the starting point for tuning, there is no fast rule for where they should be.

Carbureted:

Back out the idle speed screw until it is no longer in contact with the throttle stop lever. Now turn the screw until it contacts the lever and again 1 1⁄2 turns. Turn the idle mixture screw (on our carburetors it is typically in the center bottom of the carburetor body) in until it is fully seated - do not force the screw. Now turn it back out two full turns.

From http://www.artigue.com/fiatcontent/book ... 124_MM.pdf pages 35-36

Fuel Injected:

Run the engine to normal operating temperature. On cars with automatic transmissions, set the parking brake, block the wheels, and put the transmission in "D". Completely seat the idle speed screw. Loosen the accelerator linkage stop screw retaining nut and adjust the stop screw to achieve 800 to 900 RPM on manual transmissions and 700 to 800 RPM on automatic transmissions.

Lock the accelerator stop screw with the retaining nut. Use the idle speed screw (1) to set idle at 850 to 900 RPM on manual transmissions and 700 to 800 RPM on automatic transmissions. If idle speed cannot be reached using this procedure, fully remove the idle speed screw (2) and clean the orifice and the screw itself using a high pressure spray cleaner (carburetor cleaner is fine).

From http://www.artigue.com/fiatcontent/book ... 124_MM.pdf pages 48-49

Note that on a fuel injected car the most overlooked problem causing area is the o-ring on the idle speed screw. It can allow all manner of unmetered air that causes lean conditions, pops, poor starts, bad acceleration, and difficulty tuning. Simply remove the screw and replace the ring with a good piton ring from your local Ace. I also coat the threads with a little bit of non-hardening permatex.

[bradartigue]

Also note on FI cars with the double-nut on the throttle cable that both nuts are on the outside (firewall side) and one sets the position, the other locks the first nut. This should be set so that the cable has tension and deflects only about 2mm. This setting is relative to the position of the throttle stop screw as determined in the process I described above.

[joelittel]

its a fuel injected 80. Thanks guys.