420A why is my coolant temp gauge spiking on ms

[daveeclipse99]

i have had megasquirt ecu in my 420a for a while . now my car wont start and the coolant temp sensor gauge is spiking for -40 to 150 degrees ! is it a bad sensor ? or do i need to calibrate the sensor again ? please help

 

[#40Fan]

The sensors are cheap, so replacing it would let you know right then and there whether that is it. Make sure that your ground for the sensor is still good. Normally when the sensor goes bad, MS will revert to 170 or 180*.

 

[VelocitàPaola]

The sensors are cheap, so replacing it would let you know right then and there whether that is it. Make sure that your ground for the sensor is still good. Normally when the sensor goes bad, MS will revert to 170 or 180*.

But if the circuit is open, it'll read -40*. So, just to confirm what #420Fan suggested, check the sensor's connection to ground, then replace it if necessary.

 

[xceler8]

Do what previously mentioned.

Just a reminder, if your driving and logging and you happen to see spikes in coolant temp, you might want to take a look at your timing and afr, this can be commonly viewed as knock!

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