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SoCal Driver SoCal Driver is offline
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Join Date: Feb 2002
Location: Costa Mesa
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There are three types of idle control valves. The early ones have a heated element that expands and closes the gate valve. Actually a knife valve. The later 944's have an active valve (more of a servo really) that can be driven open and closed by placing one lead on the #2 pin and a lead on either the #1 pin or #3 pin to open and close the valve.

Then there is the third kind that is found on the 944S's and 968's that is kind of a servo and kind of a spring valve. Has a voice/solenoid coil in it that is driven with a variable current that constantly adjusts the air valve against a spring.

All can be cleaned with solvents. Carb and brake cleaner, WD-40, PB Blaster. Just don't dunk it into a carb cleaning tank! No full immersion.

The 924S has the second type as do most of the later 944's. Note this is one of the differences when transplanting a later DME and AFS into an early car. However since the power for the early idle control valve comes off of the fuel pump contacts of the DME relay the wiring to the early DME plug is non existant. Which means you can not use the later idle control valve in the early 944's with out changing the harness. But you can use the AFS and the DME.
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Old 01-01-2006, 08:05 AM
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