Oil Temp sender for FAST EFI?

[69hugger]

Guys,
I am trying to add an oil temp sensor input to my FAST XFI system. It needs to be a 3 wire sender...(5v., signal out, & and ground). All the temp sensors I can find have only 2 conductors. I have checked with FAST, (no help) and looked at various Corvette oil & coolant temp sensors, they are all 2 wire as well.
FWIW, I can find all kinds of 3 wire, 5 V. pressure transducers, but not for temperature.
Any ideas?

Thanks!!

[carbuff]

Just curious, is the need for a 3-wire a FAST requirement? I use the LS sensor in my oil pan, but it's a 2-wire I believe (with the Holley HP system).

[69hugger]

Originally Posted by carbuff

Just curious, is the need for a 3-wire a FAST requirement? I use the LS sensor in my oil pan, but it's a 2-wire I believe (with the Holley HP system).

It is. FAST offers an optional harness for analog input of up to 8 additional channels to monitor pressures, speeds, temps, etc. I am using 2 of those for oil pressure & fuel pressure, which work fine using inexpensive transducers from E-Bay.. You can also use them for D/S speed, accelerometers, etc. Although the instructions state oil temp is a useful input, FAST doesn't offer a sensor, nor can I find one available. My 1st thought was to use another CTS, which FAST told me should work fine. So I installed one into my pan. I then realized it is only a 2 wire sensor, and won't communicate with the ECU, which requires a 3 wire sensor. FAST now told me they thought a 97-98 Vette uses a 3 wire oil temp sensor. From what I've found, they are all 2 wire, the same as the CTS I already have. Now, I'm stuck.

[carbuff]

Got it...

I googled, and found this page which shows how to add an inline resistor to convert a 3-wire harness to use with a 2-wire sensor. I didn't read it in detail, but I imagine something like this is what you need, so it might be a place to start:

https://www.autosportlabs.net/RaceCapturePro_Sensors

This is creating a voltage divider, allowing the ECU to read the varying voltage at the analog input. The sensor itself is a variable resistor I believe.

Also check out the first post in this thread, which says the 98 LS1 had a 3-pin CTS sensor. Not sure if you could use that?

http://www.thirdgen.org/forums/ltx-l...formation.html

Maybe some of this will help...

[69hugger]

Originally Posted by carbuff

Got it...

I googled, and found this page which shows how to add an inline resistor to convert a 3-wire harness to use with a 2-wire sensor. I didn't read it in detail, but I imagine something like this is what you need, so it might be a place to start:

https://www.autosportlabs.net/RaceCapturePro_Sensors

This is creating a voltage divider, allowing the ECU to read the varying voltage at the analog input. The sensor itself is a variable resistor I believe.

Also check out the first post in this thread, which says the 98 LS1 had a 3-pin CTS sensor. Not sure if you could use that?

http://www.thirdgen.org/forums/ltx-l...formation.html

Maybe some of this will help...

Bryan,
You are spot on with both options. I was told by an EFI tuning expert about the resistor work around. Also found the 90-96 Corvette uses the 3 wire sender. I have ordered one of those.

You are WAY better at 'net searches than I am. I had looked for hours, and didn't come up with the info you did.

Thanks for your help! I appreciate it.

Bill

[carbuff]

Glad I could help... I googled "3-wire oil temp sensor" and started going through the images, not the search links. The images got me to the pages I posted.

Hope it all works out!