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SrRaycer
01-22-2020, 07:39 PM
Hello, I have an S13 SR20 and I'm having a problem with my coolant sensor. I'm using an AEM Series 2. The problem is that the voltage from my coolant sensor doesn't change accordingly with temperature. The voltage is always in the range of 3.4 - 3.7v, in 35 degree F temps all the way until its warmed up. I have checked voltage on the wires and it is receiving 5 v. I tried the factory sensor, then I tried a GM sensor, same problem.

The coolant sensor is a 2 pin type, it gets a ground and a signal. This confuses me a bit, shouldn't it then be a 3 wire sensor like a GM map sensor, that gets a ground, a 5 volt, and then the third wire sends the ecu a voltage signal. How can this coolant sensor do all 3 jobs with just 2 wires? I'm unsure of what to do next. All help is greatly appreciated, thank you.

S14rebuild
01-22-2020, 07:59 PM
S13 sr coolant sensor for the ecu is 2 wire...it grounds thru the block. Make sure the threads are good and clean. It uses a copper crush washer to seal so no thread sealant is used.

nick_d_240sx
01-22-2020, 08:02 PM
Thermistors, derived from the term thermally sensitive resistors.

Not sure on the AEM series 2, but a quick search of the instruction manual for the 30-6601 all I could find was:

Pin 18 ECT Sensor Coolant Input PnP for Coolant Temp Sensor

See page 10.
https://www.aemelectronics.com/files/instructions/30-6601%20Series%202%20Plug%20&%20Play%20EMS.pdf

Can you calibrate the sensor? Say's it's PnP..

SrRaycer
01-22-2020, 08:48 PM
Yes, I can calibrate the sensor, but that doesn't help if the voltage range is so narrow. There is an option in the software to choose the Nissan coolant sensor but it's not reading temps correctly, none of the sensors I tried are reading correctly. So I think I have a wiring issue. This is messing with my tuning because I have to manually raise the fuel for cold starts, then lower it once the car is warm.

So the sensor grounds through the block... does that mean that one sensor pin gets 5v and the other pin goes to ecu coolant sensor input? thanks for the quick replies btw.

S14rebuild
01-23-2020, 05:43 AM
So the sensor grounds through the block... does that mean that one sensor pin gets 5v and the other pin goes to ecu coolant sensor input? thanks for the quick replies btw.


Correct.....