Difference in coolant neck sensor's

[Dali]

I feel like a idiot for asking this, what is the difference between the coolant neck sensor's, from having the one sensor to having the two sensor's. There are the two sensor's, rear for fuel and front one for fan. Does the newer one style sensor read for both? Reason I am asking is that we picked up a 94 with a replaced k8 motor in it, the engine's coolant neck has the two sensor's on it but the wiring only has the one plug for the sensor, not two of them. The problem is it will not run properly until the motor is at normal running temp, until it reaches that the idle fluctuates up and down, as well the car overheats apparently. I have not had a chance to put insurance on it to drive it around to see what is wrong with it. any idea's, thanks.

[mikeinaus]

i dont know about the 1st sensor being different between years and i dont think your problems would have to do with the 2nd sensor. as far as i know the ecu only uses the readings from the 2nd sensor when the car is warm. if your ecu isnt programmed to use the 2nd sensor it shouldnt need it.

i just checked the online manuals and it looks like the resistance readings from the coolant sensor are the same for 92 and 95 so i doubt thats your problem. unless your sensor is garbage. theres a way to test it outlined in the manual.

[mxmikey]

I just replaced the green sensor (for the fuel my scanner code was 09 for water temp sensor), it looks like the new ones can be used for either one, at Advanced Auto that was the only coolant sensor they had (I had to make sure because every time I get a part the parts store manages to mess it up two or three times minimum no matter where I go). The new ones don't have the guides like the original sensors. Before I replaced it the car would randomly have trouble starting where it would flood the car, I had to then reset the computer and unplug the fuel injectors to clear it out and after it would start, also when I was driving the car would randomly sputter it felt like I was starting off in third gear literally jerking the car. For your fan you could always bypass it to a constant power source so it always on.

[solo_ryder]

Yes, the sensor in the 94+ motors act as two sensors in one. However, the sensor on the rear of the 94 motors should be the same as the one on the 92-93 motors, its the ecu that is different and regulates how the sensor works. The 94 ecu is a K834 ecu

[Newfie_dan]

the single wire coolant sensor is for the dash gauge only, the 2 wire is for the ecu.

[_-Night-Shade-_]

Yeah I'm pretty sure the 2 coolant sensors are exactly the same, they are probably just color-coded to match the harness.