Use stock coolant temp sensor for aftermarket gauge?

[2plus4plus0eq6]

Hello,

I have been searching for some information and couldn't find it. I am looking to hook up an aftermarket water temp gauge inside of my engine bay. Is it possible to tap off either the engine coolant temp sensor (2 wire sensor for ecu) or the gauge coolant temp sensor (1 wire sensor for the dash)?

If its not totally accurate is it also possible to put in a resister to correct the readings?

Any help is appreciated. thank you.

EDIT: I think it might be possible because according to this link here (http://www.frsport.com/DIF-Dual-Fan-Controller-Install-on-S13-S14-240SX_t_22.html), the fan controller is being hooked up from the engine coolant temp sensor.

[Ilya]

Hello,

I have been searching for some information and couldn't find it. I am looking to hook up an aftermarket water temp gauge inside of my engine bay. Is it possible to tap off either the engine coolant temp sensor (2 wire sensor for ecu) or the gauge coolant temp sensor (1 wire sensor for the dash)?

If its not totally accurate is it also possible to put in a resister to correct the readings?

Any help is appreciated. thank you.

EDIT: I think it might be possible because according to this link here (http://www.frsport.com/DIF-Dual-Fan-Controller-Install-on-S13-S14-240SX_t_22.html), the fan controller is being hooked up from the engine coolant temp sensor.

Sure, once you test and find out the non linearity of sensor aka at what temperature range the sensor outputs a linear voltage. Typically, the display circuitry is built around that non linearity. It will work, but I wouldn't trust it much since you do not know the output function on the sensor nor the transfer function of the temperature display.

Example: sensor one outputs the following-
20C = 0.2 volts
25C = 0.4 volts
30C = 0.5 volts
35C = 0.6 volts
40C = 0.8 volts
50C = 0.95 volts

As you can see, the linear region of the sensor is between 25-35Celcius, so I would build a electronics that would use that sensor function.

[2plus4plus0eq6]

Sure, once you test and find out the non linearity of sensor aka at what temperature range the sensor outputs a linear voltage. Typically, the display circuitry is built around that non linearity. It will work, but I wouldn't trust it much since you do not know the output function on the sensor nor the transfer function of the temperature display.

Example: sensor one outputs the following-
20C = 0.2 volts
25C = 0.4 volts
30C = 0.5 volts
35C = 0.6 volts
40C = 0.8 volts
50C = 0.95 volts

As you can see, the linear region of the sensor is between 25-35Celcius, so I would build a electronics that would use that sensor function.

I see what you mean. That sounds like a pain in the ass. If I were to put in an aftermarket water temp sensor, how would I go about finding out if it will output the proper readings to a certain gauge?

[Ilya]

You don't. That's the beauty of it. People think sensors are these magical things that work with everything every time. In reality, there is some thought and engineering behind each sensor. You need to look to look for specs of the sensor and specs of the gauge.
0-90c max at 0-5 volts <- look for something along those lines for the sensor and gauge and make sure they match. You are better off keeping a finger in the coolant as it warms up and saying "getting warmer getting warmer...too warm" if you don't want to put the effort into characterizing your system.

[KoukiMonsta]

when you buy an aftermarket water temp gauge....it comes with the correct sending unit...

[2plus4plus0eq6]

You don't. That's the beauty of it. People think sensors are these magical things that work with everything every time. In reality, there is some thought and engineering behind each sensor. You need to look to look for specs of the sensor and specs of the gauge.
0-90c max at 0-5 volts <- look for something along those lines for the sensor and gauge and make sure they match. You are better off keeping a finger in the coolant as it warms up and saying "getting warmer getting warmer...too warm" if you don't want to put the effort into characterizing your system.

Thanks for the info. Makes total sense. I am embarrassed to say I have a megan racing gauge kicking around which I want to use in my engine bay. I cannot seem to find any specs on it. I've even tried googling some defi gauges and they don't even post the specs for those on their website nor do any of the senders I have seen on amazon.

I almost think people just buy whatever and put it together and think if the needle moves then its OK.

[2plus4plus0eq6]

when you buy an aftermarket water temp gauge....it comes with the correct sending unit...

ahhh.. I c. Maybe I missed that in my garage. I'll take another look. Thanks a lot

[Bushido]

FYI, don't trust the stock temperature gauge.