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Will bad coolant temp sensor affect idle?


PTAaron

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After last night's overheating/attempting to bleed coolant system adventure I let the car sit overnight. Started it this morning to continue to work on bleeding it while it wasn't extremely hot. Immediately at startup the temp needle spikes to maxed out - clearly the engine isn't that hot since it sat at 20-30 degrees all night. Idle is extremely rough - putting it into gear makes it stall.

 

Will an an inaccurate high temp reading cause this?

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WHAT CAR???

 

There may be two sensors, one to supply engine coolant temperature readings to the computer, another to drive the dashboard gauge. The dash-gauge sensor won't affect engine running. The sensor that supplies data to the computer WILL affect engine running and driveability.

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WHAT CAR???

 

There may be two sensors, one to supply engine coolant temperature readings to the computer, another to drive the dashboard gauge. The dash-gauge sensor won't affect engine running. The sensor that supplies data to the computer WILL affect engine running and driveability.

Sorry - '94 cutlass supreme - I was typing on my phone and I thought I typed that part.

My thought was bad data making the computer "think" the engine was hot when it was actually extremely cold. I just wanted to make sure I wasn't using pretend logic.

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if the ECM thinks coolant temps are much higher than they are, expect weird things to happen, like the cooling fans to kick on, along with running too lean of a fuel mixture for the engine to run reliably with cold manifolds/heads.

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if the ECM thinks coolant temps are much higher than they are, expect weird things to happen, like the cooling fans to kick on, along with running too lean of a fuel mixture for the engine to run reliably with cold manifolds/heads.

 

Thanks, that is what I was suspecting.

 

Looks like tonight will be "change the temp sensor and finish bleeding the system" in hopes that I don't have a blown headgasket as was suggested in my other thread.

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