coolant temp sensor


dirtymike

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Joined
Dec 30, 2010
Messages
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Location
knoxville TN
Vehicle Year
1987 4x4 lwb
Transmission
Manual
Having a hard time getting this 1987 2.9 manual 5 speed to idle at the correct speed. I have discovered that if i disconnect the coolant temp sensor the idle drops and it revs up fine. When i disconnect it is drops 2 to 3 hundred RPMS. on restart is goes back up until i disconnect the sensor. Any help. thanks Dirty
 


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Dirtman

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EMT / Paramedic
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May 28, 2018
Messages
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Location
Over there --->
Vehicle Year
2009
Make / Model
Ford
Engine Type
2.3 (4 Cylinder)
Engine Size
466.63 teaspoons.
Transmission
Automatic
2WD / 4WD
2WD
Tire Size
So friggin big!
My credo
Give me money.
I'm not great with the earlier trucks, but sounds more like an IAC problem. Unplugging the temp sensor puts it back in open loop mode, but if its already warm the engine is trying to "choke" it. Temp sensor is like a choke on a carb... when warm, it tells the engine to stop running rich, once warm it tells the engine to run normal. (These are called open and closed loop mode) The iac valve should be adjusting between the two modes.
 


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