There are two wires heading to the CTS on the front of the manifold of my TPI car. Does anyone know why there are two? Is one just a ground? The black one? Any help would be appreciated, thanks.

-ian

 

Well if you still have the original ECM in your car, the black wire would go to pin "B6" on the ECM and is the sensor ground there. It also has a splice in it with a wire going to pin "A" of the MAP sensor. The yellow wire would go to pin "E16" of the ECM and is the Coolant Sensor Signal there.

 

So that black wire acts as a ground for both the MAP sensor and CTS? I've got an aftermarket autometer water temp guage and sensor and I wanted to try and cut down on the clutter in the engine bay by maybe combing the stock unit and aftermarket one. Could I just cut that ground away, use the autometer unit sending to the ECM and aftermarket guage? Is the stock unit correct enough (is there a way it wouldn't be accurate?) to be used for both? (as in splice into the yellow wire for the aftermarket guage as well as the ECM?)

Thanks trickster.

 

No, because the Coolant Temp Sensor in the intake manifold has nothing to do with the Coolant Temp Sending unit located above the #1 sparkplug. Do not splice anything into those two wires unless you want some really screwed up results. The Coolant Temp Sending unit is only a single wire circuit.

 

Now I'm really confused... So I can't use the autometer sending unit, right? Because it doesn't have the right ground wire? Can I splice into the yellow wire and Y that off to the aftermarket guage and still have it be accurate for both?

 

There is nothing to be confused about. You want to use an aftermarket temp gage right. Connect it to the wire harness for the coolant temp sending unit located on the driver side head located above the #1 spark plug and ground it to the instrument panel frame inside the car. Do not and I repeat, do not splice into the yellow wire for the coolant temp sensor. If you do you will regret it later.

 

I've already got the guage hooked up and working. It came with a sending unit (electronic) and I installed that in one of the non-used plugs on the manifold. So I'm guessing that either one of them is accurate enough? When I installed the HSR manifold I had to extend (cut, splice and solder) the wires for the manifold mounted CTS; would that affect it any?

I think I'm getting this now, just find the temp sender on the drivers side head and use that? What one was that for? Just the guages?

 

YEP - the driver's side sender is just for the gauges. The front sender is for the computer to set the fueling.


- Vern