Idle speed -- CIS
 

Is there a really simple way to lower the idle speed on my 2.7 with CIS? I don't want to change any of the other settings, and don't know if it has an idle speed screw or where it might be. Thx.

I am no expert, and this may not be the best way...so that's my disclaimer.

On the left side of your CIS, directly behind tha Air Box intake is an adjustement screw...not sure of technical name for it.

I know that with the engine off, make slight adjustments (1/4 turn increments)

Clockwise will decrease idle speed

Counterclockwise will increase idle speed

As always, try to remember the original setting so you have something to fall back on.

k9handler is correct. the ajustment is also detailled in Wayne's 101 projects book. I did my 2.7 with the engine running. Make sure its warmed up completely and then set the idle to 950-1000. I did it with heat/lights off. Turning on the accessories did reduce idle a bit, so I set mine to the high end of the range.

David's advice is right on the money. The Idle Bypass Screw, designed for this exact purpose, is at the back of the throttle body (the thing with the throttle linkage on the side). the shaft of this screw faces toward the drivers' side of hte car, as opposed to the front of the car or something. On the end, for ease of adjustment, is a disk-shaped knob, at least the diameter of a nickle. Clockwise closes the bypass, lowering idle. This actually meters a bypass route for air. Air bypasses the throttle plate. At idle, the throttle plate should be COMPLETELY closed. Without this bypass, there should be no air getting into the engine. Interestingly, several of us find that our cars will idle slowly (400 rpm or so) with the bypass closed. We don't yet know why.

The above is correct. The idle speed will also be influenced by the air/fuel mixture (adjustable) and ignition timing. If you're having a problem w/ your idle speed and the idle adjust doesn't resolve the problem, you should check ignition timing & air/fuel mixture. On a 2.7 car, you'll have to take it to a shop to have the AF mixture checked, but ignition timing is a DIY job.

Greg (where IS that diploma?)
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