Look at the attached jpg https://www.rx7club.com/forum/attach...postid=1451627

Look for the pin 2I. It's labled as a GW wire. That is green/white or green with a white stripe. It runs directly from the water thermo sensors plug straight to the pin 2I on the ECU's middle plug. The other wire is identified as a brown/black, or brown wire with a black stripe. It is spliced in with several other wires that are also brown/black, but in the end they all end up at pin 2C on the ECU.

The ECU Plug ........are labled from the right to the left when you look at the plug from the rear where the wires enter the plug.

The far right, top wire is pn 2A. The wire directly below it is pin 2B. So pin 2I is on the top row, fifth one over from the far right and is a green/white wire.

There should be no reason for running a new wire. Ohm out the existing wire from one end to the other. If it reads less than 3ohms all is well with that wire.

The black wire at the sensor should ohm out to pin 2C on the ECU. That should be the second pin on the middle plug, counting from the right to the left.

On some cars the brown/black wire is just a pure black wire.

 

thank you so much HAILERS I dont know what you told me but you did something right cause it now works....

but 1 more thing please... its comming up as .26v all the time so does that mean I have my new waterthermo connected backwards or is the car saying I have a break?

 

bump

 

bump

 

bump

 

It should never read that low. With a engine running water temps in the 200 degree range the output of the water thermo sensor will be approx .4 volts. See what I mean?

I'm at a loss as to what is wrong.

It's really just a two wire circuit. You've a green/white wire for the output and the other wire is a ground.

I just went out to my 87 that hasn't been started this day. I figure the water temp is probably about 70 degrees (guess). I put the positive lead up the backside of the green/white wire and the negative lead on the attach stud for the ECU. Turned the key to ON and have 2.07 volts.

If I had started that car, as the water warmed up and reached around 180 degrees, then the voltage would have dropped down to approx .5 volts.

Hmmm...I get 2.07 volts when cold and you wrote something about .26 volts. Hmmmmm. Misreading the meter?? Got me.

 

I dont think im misreading the meter cause its digital...
but you never know ....every pin ive tested comes out below what it is supposed to... if the voltage is supposed to be around 5v it comes up around 1.2-.9v instead... maybe I should reset the ecu??

 

should I go about rewiring the whole sensor?
I dont like the thought of cutting a wire close to the ecu but if you guys think it needs to be done