I have an '83 Bonneville with the 231 v6 and have been having issues with the idle speed control motor. It's a four wire setup on this car. All wiring is correct and intact but when the coolant sensor is connected, the ISC constantly retracts, retracting faster with a higher RPM, setting a code "shorted throttle contact switch" and will likely eventually burn the motor out in the ISC. Coolant sensor is new and tests ok with ohmmeter. If I disconnect the coolant sensor the ISC plunger comes back out and works properly letting the throttle down slowly after higher RPM's and regulating idle. I tried two ECM's and both do the same thing and both are correct for the car. The car came with a reman ECM and with that hooked up, the ISC doesn't move at all either way. If I ground the test terminal under the dash the ISC moves in and out as it should. I'm not sure if any of the ECM's are good, though they flash codes as they should, all other sensors work and the car runs fine.
I have checked everything, from the TPS (which has no effect), to every other sensor under the hood (and disconnecting them to see if they are affecting it somehow)and the grounds, as well as what the service manual suggests. I cannot get this to work properly. Only things I haven't tried would be a brand new ECM and new ISC motor. The motor and contact switch all test fine. Any ideas? :?
I have checked everything, from the TPS (which has no effect), to every other sensor under the hood (and disconnecting them to see if they are affecting it somehow)and the grounds, as well as what the service manual suggests. I cannot get this to work properly. Only things I haven't tried would be a brand new ECM and new ISC motor. The motor and contact switch all test fine. Any ideas? :?
