How to Fix the Idle Control Valve in a Cadillacby Lee Sallings
The idle control valve on a Cadillac compensates for changes in the required air-fuel ratio of the engine by allowing more or less air into the engine. When the engine needs more air to raise the idle speed, such as in cold engine operation or when the air conditioner compressor comes on, the valve opens and passes more air. When the engine needs less air, such as in warm engine operation or when the air conditioning is off, the valve closes and less air is supplied to the engine.
Unplug the electrical connector on the valve by lifting the locking tab while pulling the connector out of the valve. Remove the 8mm bolts that attach the valve to the throttle body. Pull the valve off the side of the throttle body.
Bolt the new valve and new gasket onto the side of the throttle body. Tighten the bolts securely. Plug the electrical connector into the valve.
Start the engine and turn it off. Unplug the electrical connector from the valve. Start the engine and adjust the idle speed screw on the throttle body, using a screwdriver, until the engine idles at 675 rpm.
Start the engine and adjust the idle speed screw until the engine idles at 650 rpms. This sets the base idle speed to a place where the valve can have full control. Turn off the engine. Plug the electrical connector back into the idle control valve. Start the engine. Verify the control of the idle speed by turning on the air conditioning and observing the change in idle speed when the compressor comes on.
- Wear safety glasses and work gloves when working around a running engine to prevent injuries.