Idle speed on fuel injection

[littleorange124]

My 1981 fiat spider is idling at 2500 rpm which sounds way to fast what is it supposed to idle at?

[4uall]

850-900

this might help

Step Zero: Test your brake booster connection. Unplug the brake booster hose at the manifold and block it off with a cap. Drive the car. Did the problem go away? Keep in mind the brakes will be a little harder to press but if the car runs perfectly or very differently (high/low idle, etc) with it unhooked then it leaks; fix it.

If that isn't it then remove the air bypass screw and clean the orifice and the screw. Replace the o-ring. Fully seat the idle air bypass screw. Slacken the throttle cable nuts so there is no tension on the throttle. Start the car and warm to normal (two fan cycles). Set the stop screw to 800 RPM. Set the air bypass screw to bring the idle to 850 RPM.

Drive it. Is the problem resolved? Yes, great, no, read on:

Test the throttle position switch (I can't recall the values, go to http://www.artigue.com/fiat and download the book I wrote on it, or look in your shop manual). If off then set correctly.

Drive it. Is the problem resolved? Yes, great, no, read on:

Stop the car and manually advance the motor to line up the crank at TDC and the cams at the alignment holes. Does it line up perfectly? No? Reset timing belt. Yes? Attach timing light and start motor. Set timing to 10 degrees behind top dead center with the diaphragm vacuum line pinched.

Drive it. Is the problem resolved? Yes, great, no, read on:

Stop the motor. Check that the distributor vacuum advance works by drawing vacuum. Does it hold? If you don't have a handpump then blow into the line (don't suck - if the diaphragm is bad you'll suck in dirt!). Solid? If not then replace. If so then read the plugs. Brown to brownish white = normal; black = rich; white = lean. Which is it?

Brown to brownish white? Yes, great, no, read on:

Test the AAR operation (see my book). Using propane (not fire, just a light amount of propane from a small tank) around the air hoses try and find a leak. If the engine speed goes up when you place propane near the hose then you've found one.

http://www.fiatspider.com/f08/viewtopic.php?f=5&t=18519

http://www.artigue.com/fiat/

[KevAndAndi]

Yes, that is way, way too high.

Totally agree with Brad Artigue's methodical approach as posted by Jay. But to eliminate the most obvious cause, first see the link Jay provided pertaining to idle speed adjustment; I would call that "Step -1".

You didn't mention the positions of the idle speed screw and the throttle stop screw. If, for example, the former is fully seated and the latter is barely touching the plate, then you definitely have a problem to troubleshoot. While you're fiddling with the idle speed screw, you might as well remove it and check the condition of the o-ring. I found that mine was bad, and I found another major air leak at the junction of the air flow meter and the big air hose. Make sure all connections and clamps are tight, and inspect hoses for obvious leaks - particularly the big air hose. Follow all of Brad's steps to hunt down even the less-obvious leaks, and your idle will be mellow in no time.