Does anyone know if eliminating the coolant thermo switch on a stock ECU'd 3rd gen will cause any performance issues (i.e. is the switch used for anythinng other than turning the fans on?). I will be running a PWM fan controller and want to locate my NTC temp sensor in the current thermo switch location.

Any info would be greatly apreciated,

Glenn

 

Anybody?

 

NO! dont remove it! it tells the ECU what temp the engine is running at, if you remove it, you will have many problems...stalling out, bad mileage, etc etc

 

I agree with above, don't remove it. Also, where did you get the PWM fan controller?

 

Could you guys be confusing the coolant thermal swtch and the NTC coolant thermal sensor? They are both located on the backside of the thermostat housing. The coolant switch is black and has one wire connected to it (grounded through the switch body). The NTC "thermistor", or coolant temp sensor, is green and has two wires connected to it.

The NTC sensor is used by the ECU to determine engine temperatures and must be maintained. I am not certain if the temp switch is used for anything other than a "trigger" for the ECU to turn the fans on.

Any additional thoughts on this?

As for the PWM controller, I am building my own. I am a few months away from a working propotype.

Glenn

 

glemmers, you're correct. You can remove the fan switch with no ill effect as far as the ecu is concerned, though you may need to add a resistor to keep the CEL from coming on. The thermosensor on the otherhand you must leave in place as the ecu uses that for fuel and timing calculations.

 

ok, i thought he was talking about the coolant thermosensor, which according to fsm, sends info to the ecu...

 

ditto

 

Thanks guys.

I tested the switch last night. From 70°F to 212°F, it is open (used boiling water, so couldn't test to any higher temps). The service manaul states that at 214°F, the switch should go closed, and then by 226°F, it should openagain. So, disconnecting it shouldn't cause problems (?).