idle control valve
03-02-2003, 08:58 AM
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idle control valve
Need to know where the power and ground comes from that controls the idle control valve. The prints in the Haynes manual are unclear. Also what pins on the idle conrol valve do you use to bench check it. When I disconnect the plug the idle speed does not change.
Thanks
86 944 N/A
Thanks
86 944 N/A
03-02-2003, 01:55 PM
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Interesting...it looks like the idle speed positioner changed from a three wire to a two wire connection in 87.
In the 86 944,
pin 1 is connected to the DME (Black/RED)
pin 2 is connected to 12VDC (Blue/Red)
pin 3 is connected to the DME (Black/White)
Pins 1&3 are pulsed low (ground) by the DME, one opens the valve, the other closes the valve.
In a 87 944S
pin 1 is connected to 12VDC (Blue/red)
pin 2 is connected to the DME (black/red).
The DME pulses the signal low to activate the positioner.
Bench testing is going to be problematic since the DME pulses the signal line(lines) and I for one don't know what the pulse duration or period is. What I would do is to remove the positioner and spray some WD-40 inside of it to get rid of carbon buildup. Some people use carb cleaner but you have to be careful because it will melt plastic after couple of minutes of contact. With the positioner connected, and the ignition on, you should see the control valve inside moving slightly.
In the 86 944,
pin 1 is connected to the DME (Black/RED)
pin 2 is connected to 12VDC (Blue/Red)
pin 3 is connected to the DME (Black/White)
Pins 1&3 are pulsed low (ground) by the DME, one opens the valve, the other closes the valve.
In a 87 944S
pin 1 is connected to 12VDC (Blue/red)
pin 2 is connected to the DME (black/red).
The DME pulses the signal low to activate the positioner.
Bench testing is going to be problematic since the DME pulses the signal line(lines) and I for one don't know what the pulse duration or period is. What I would do is to remove the positioner and spray some WD-40 inside of it to get rid of carbon buildup. Some people use carb cleaner but you have to be careful because it will melt plastic after couple of minutes of contact. With the positioner connected, and the ignition on, you should see the control valve inside moving slightly.
