converting 2wire water temp sensor into 3wire ???

[ACII]

Hy all

unfortunately i only have the 2wire sensor installed....so i dont have a wire for my water temp gauge....

But nevertheless...if i do have a 2 wire sensor , i could splice off the wire which goes to the computer ..so with the added wire i could go directly to the water temp gauge .!!!

Or does that occur some trouble signals to the PCM ??


Thanks a lot
Achim

[ls1nova71]

You can't do that, it will give a false reading to the PCM. If you want to use a 3wire sensor, then you need to order one for a 98 F body, then get the pigtail for it and splice it into your harness. The third wire will go to the gauge. That said, depending on what gauge you have, it may or may not be accurate.

[ACII]

alright....thanks for information

...than i will go with the solution on the rear side of the passenger side head....

i do have plenty of space there....so i wont have problems with heat soak

CU
Achim

Originally Posted by ls1nova71

You can't do that, it will give a false reading to the PCM. If you want to use a 3wire sensor, then you need to order one for a 98 F body, then get the pigtail for it and splice it into your harness. The third wire will go to the gauge. That said, depending on what gauge you have, it may or may not be accurate.

[scottybaccus]

A little more info...

The ECM uses the two wire sensor to modify a 5 volt reference signal. It only means anything to the ECM. Your gauge has voltage applied to the gauge, and then gets a ground through the sensor, which provides a variable resistance to move the needle around. I laid one wire alongside the LS harness, from the sensor, to the back of the motor, and spliced it into the factory temp sensor wire, then I swapped the sender for the three wire unit from a '98 Camaro. (I'll confirm that) I cut the connector off the harness and replaced it with the 3 wire pigtail. The blue wire on the pigtail connects to your original gauge extension, the other two go to the LS harness, and it isn't important which is which, but colors should match, anyway.

Part numbers:
sensor- 12551708, TU280, TX111 or 1T1081, $15-$25
pigtail- 1P1065, S619 or PT2319, $15-$30

I have found this works great on my '87's factory gauge. It hits the 1st line at 1/3 scale at 200*. That's pretty much where it stays.

[ACII]

Thanks for detailled information ...

I am living in Germany..so it is not that easy to get the parts.. so i will go with the passenger side head...

From my old setup ..i already do have a gauge with the 1/8 npt sender.so i just need the adapter M12 to 1/8 (thats easily to get here in Germany) :-)

Cu Achim

Originally Posted by scottybaccus

A little more info...

The ECM uses the two wire sensor to modify a 5 volt reference signal. It only means anything to the ECM. Your gauge has voltage applied to the gauge, and then gets a ground through the sensor, which provides a variable resistance to move the needle around. I laid one wire alongside the LS harness, from the sensor, to the back of the motor, and spliced it into the factory temp sensor wire, then I swapped the sender for the three wire unit from a '98 Camaro. (I'll confirm that) I cut the connector off the harness and replaced it with the 3 wire pigtail. The blue wire on the pigtail connects to your original gauge extension, the other two go to the LS harness, and it isn't important which is which, but colors should match, anyway.

Part numbers:
sensor- 12551708, TU280, TX111 or 1T1081, $15-$25
pigtail- 1P1065, S619 or PT2319, $15-$30

I have found this works great on my '87's factory gauge. It hits the 1st line at 1/3 scale at 200*. That's pretty much where it stays.

[RaceAGMC]

Originally Posted by scottybaccus

A little more info...

The ECM uses the two wire sensor to modify a 5 volt reference signal. It only means anything to the ECM. Your gauge has voltage applied to the gauge, and then gets a ground through the sensor, which provides a variable resistance to move the needle around. I laid one wire alongside the LS harness, from the sensor, to the back of the motor, and spliced it into the factory temp sensor wire, then I swapped the sender for the three wire unit from a '98 Camaro. (I'll confirm that) I cut the connector off the harness and replaced it with the 3 wire pigtail. The blue wire on the pigtail connects to your original gauge extension, the other two go to the LS harness, and it isn't important which is which, but colors should match, anyway.

Part numbers:
sensor- 12551708, TU280, TX111 or 1T1081, $15-$25
pigtail- 1P1065, S619 or PT2319, $15-$30

I have found this works great on my '87's factory gauge. It hits the 1st line at 1/3 scale at 200*. That's pretty much where it stays.

I did this and then installed an adjustable resistor in line to my factory gauge, so I could adjust it to run straight up when it was at normal operating temp.

[Gooker928]

The camaro sensor is the way to go.
You just have to splice it in and run one wire.
I have tapped the head before but prefer not to do it that way.