Temp sensor with voltage output

Information and discussion of EFI hardware and specifications
Posts: 149
Joined: Wed Oct 31, 2012 6:59 pm
Location: Sydney

Temp sensor with voltage output

Postby 0081(2) » Thu Nov 13, 2014 8:24 pm

Does anyone know where i can find a temp sensor that has a 0 to 5 volt output that's suitable to be installed on water?
I would like to be able to log pre and post my heat exchanger for my water to air intercooler system and have not had much luck.

From what i can find i would need a IC temperature sensor as they have a linear output but i have not been able to find one that would work for what i need.

Something like this would be perfect
Temp switch.JPG
Temp switch.JPG (22.26 KiB) Viewed 3735 times
Last edited by 0081(2) on Thu Nov 13, 2014 9:14 pm, edited 1 time in total.

Site Admin
User avatar
Posts: 5762
Joined: Sat Feb 28, 2009 8:34 pm

Re: Temp sensor with voltage out put

Postby antus » Thu Nov 13, 2014 8:27 pm

Why not set up an '808 on the bench with a stock coolant sensor and log it with tuner pro? even if you remove the sensor you can use the curve map from a stock tune.
Have you read the FAQ? For lots of information and links to significant threads see here: viewtopic.php?f=7&t=1396

Posts: 149
Joined: Wed Oct 31, 2012 6:59 pm
Location: Sydney

Re: Temp sensor with voltage out put

Postby 0081(2) » Thu Nov 13, 2014 8:51 pm

antus wrote:Why not set up an '808 on the bench with a stock coolant sensor and log it with tuner pro? even if you remove the sensor you can use the curve map from a stock tune.


Hey antus.
I dont quite follow how that would work for what i need.

Im using a flash PCM from a V6 VY and have limited inputs to use which are only 0 to 5 volts and i wish to log the temps when driving.

User avatar
Posts: 9788
Joined: Sat Feb 28, 2009 9:05 pm
Location: Tenambit, NSW

Re: Temp sensor with voltage out put

Postby Holden202T » Thu Nov 13, 2014 9:09 pm

I think what antus means is if you connect it to the 808 you can see what volts = certain temps so you'll know what settings you need for it to display correctly

Posts: 149
Joined: Wed Oct 31, 2012 6:59 pm
Location: Sydney

Re: Temp sensor with voltage output

Postby 0081(2) » Thu Nov 13, 2014 9:18 pm

I was under the impression that the stock sensors are a restive type sensor not a voltage sensor ??

I thought as a general rule a 2 wire sensor was a resistance type and you needed a 3 wire sensor for voltage output sensor (power, ground and output.)

Site Admin
User avatar
Posts: 5762
Joined: Sat Feb 28, 2009 8:34 pm

Re: Temp sensor with voltage output

Postby antus » Thu Nov 13, 2014 10:18 pm

I would have thought it would have worked, but I admit I havnt looked at the wiring. I thought you were homebrewing the electronics and/or just looking for a way to measure temp as you didnt mention the pcm.
Have you read the FAQ? For lots of information and links to significant threads see here: viewtopic.php?f=7&t=1396

User avatar
Posts: 4991
Joined: Sun Mar 01, 2009 2:54 pm
Location: Perth, WA

Re: Temp sensor with voltage output

Postby VL400 » Thu Nov 13, 2014 10:33 pm

A normal resistive temp sensor is converted to a voltage by using a pullup resistor of a known value and a stable voltage reference.

Take the tables from 11P for coolant sensor calibration...
temp senders.png
temp senders.png (23.88 KiB) Viewed 3707 times


There are two tables as the PCM switches the pullup resistor due to the extremely non-linear resistance of the sender depending on the coolant temp. The ADC counts is the raw data your analog input would read, then in TunerPro you can enter the table values for it to interpolate from to get degrees C.

The water temp you want to measure will decide the pullup resistor value, if its going to be below 60 odd degrees go with 3840 ohms (3900 ohms is closest in your common values without resorting to a trimmer pot or more expensive resistor for an exact value).

Use the TPS 5V as your stable voltage source and you will have a nice accurate temp reading using the factory calibration data :thumbup:

The Ecotec coolant sender is a little different if you use that...
temp sender ecotec.png
temp sender ecotec.png (22.38 KiB) Viewed 3707 times

Return to Hardware

Who is online

Users browsing this forum: No registered users and 1 guest