What sensor is this...

[KlingonFiero]

Thanks a lot for the pics!

I think I have this particular issue about figured out now

I will be getting me the 3-wire CTS - a most excellent change in sending units!!! I guess I will be hitting ACE Hardware too - need a plug now...

Now all I need to do is figure out the plumbing and the Air Intake setup...

[3100 MPFI]

I just left the sensor in there, and cut the pigtail off. I didn't want to deal with plugging it up. If I ever get that area exposed again, I will just use the plug from my spare heads. Seems to be fine for now.

LOL

[KlingonFiero]

I just left the sensor in there, and cut the pigtail off.

LOL

I guess I could do that... But it is real easy to get to that side of the engine, seeing as it is in a Fiero

[3100 MPFI]

true

[3100 MPFI]

Here are some more pics.

This is the rear 3.1 head with the sensor still in it.


Here is the 3 wire connector in my old 3100 lower intake manifold with the 2 wire sensor next to it.


And a connector view of the 2 sensors.

[KlingonFiero]

Very Cool!

Thanks for the extra pics.

I picked up a 3-wire CTS yesterday.

There are three wires; Black, Yellow, and Green.

The green is to the ECM. Not sure about the Black or Yellow.

Is the Yellow the Gauge or the Idiot Light?
Is the Black the Gauge or the Idiot Light?

Thanks!!!

[3100 MPFI]

In my car, the GREEN is for the gauge, and the YELLOW is for the computer, and the BLACK is for the SENSOR GROUND.

Green goes to cluster, and yellow and black go to the PCM

[KlingonFiero]

In my car, the GREEN is for the gauge, and the YELLOW is for the computer, and the BLACK is for the SENSOR GROUND.

Green goes to cluster, and yellow and black go to the PCM

That kinda defeats the pourpose of having a 3-wire CTS...

I will have to do some checking, need to find a schematic.

My understanding is that the CTS grounds through the case (i.e.: the engine block) and the three wires are for thre diferent things. The idiot light, the Gauge, and the ECM.

[3100 MPFI]

not for the 3100.

If you want, i will scan the wiring diagram saying the black wire is a sensor ground.

I will do it anyways. It is always good to have info like that in the system.

[3100 MPFI]

here are the wiring diagrams. There are 2 of them. The first one is for the PCM part. It coveres the YELLOW and BLACK wires.



Here is for the CLUSTER, and it covers the GREEN WIRE. The temp sensor is on the bottom right of the page.



Sorry for the sucky pics. The binding has come off of my books, and it is hard to click and hold the book at the same time.

These were scanned from the 1996 GM W-body service manual.

Also the PCM diagram is for the 3100 computer, and the gauges cluster was from the CHEVY, OLDSMOBILE, PONTIAC pages.

[KlingonFiero]

Well, I guess I am wrong
You learn something new everyday!

I guess I will still have to use two CTS units then

The Fiero gauges are not setup to turn on the warning light via the gauge... Oh well. At least I do not have 3 CTS' like the original setup required.

Thank you very much for the scans - very helpful!!!

-Don

[bszopi]

If you have a guage, do you really need the idiot light as well?!?

[Guest]

If you have a guage, do you really need the idiot light as well?!?

LOL, not really, but it is nice to have a light that comes on, when you are over heating or close to. I will be doing this in my Jimmy along with a low oil pressure light, I like having that "Hey look at me you idiot, you forgot to look at your gauge" bright light blaze at me in the face, it helps to diagnose problems too, when they arise.

You can use the 3 wire to run the gauge and ECM and then add another probably single wire sender for the light.

If you really wanted to, you could make a circuit that monitors the resistance (voltage differential) on the gauge wire and trigger the light to come on at any point you want, make it adjustable.