I know the water thermal sensor is supposed to be an important thing to have functioning correctly because it will adjust fuel according to the temperature of the coolant and can lower your gas mileage. Where does the water thermal sensor connect to on the wiring harness and where can I buy a new one?

 

No one wants to answer questions that've been asked and answered a million times before...

 

search for water thermo sensor

 

After doing some searching, all I can find is where the sensor is located. Of course I know where it's located, but I'm wondering where the wire is that's supposed to connect to it. I can't seem to find it. Any idea what color it is and what other wires are bundled together with it?

 

green square plug (same as bosch style injector connectors with metal clip). going off of memory but I'm pretty sure its on the same branch of the harness as the TPS and AIT connectors.

double check the wiring diagram

 

Yea, I know what it looks like, but couldn't find the wire it's supposed to connect to. Does anyone have a picture of it connected?

 

It should have two wires on it. One green/white and the other pure black or in some cases a brown wire with a black stripe (brown/black).

The wires are on a branch of the harness that shares the front primary and front secondary injectors.

 

Would that not be in the FSM wiring diagram? Thanks for donating your expensive time to posting that HAILERS.

 

Alright, thanks for the info guys. I'll see if I can find the wires tomorrow once I take the care to school.

 

Well, I still can't seem to find the wires. I have read many places and seen in the factory wiring diagram that it's a green/white wire and a black or brown/black wire. I've torn apart the wiring harness and found a green/white wire, but it doesn't go to the thermo sensor. Could anyone run outside and take a picture of the two wires and the connector quick?

 

Hope this helps...hey, make sure you didn't somehow steal the plug from the sensor and put it on an injector...not sure that's even possible, but I've seen some funny things.

The plug on the picture is green and full of sanding dust...best I have for now.

 

Yea, I saw that picture before. I need an actual picture of the two wires that it uses. I just tore apart the wiring harness from the inner fender well to the primary fuel rail and only found one green/white wire, which was plugged into the primary fuel rail. I seriously doubt that's the water thermal sensor wire since it's way longer than what it would need to be. Can anyone get a better picture?

 

Your car is seriously screwed up.

No injector gets a green/white wire. No model ever made. Therefore your injector wiring is put on wrong.

Seriously speaking, download the wiring diagrams for the series four and look at the Fuel and Emissions pages. It shows all the wiring for all the sensors.

One wire on EACH injector will be black/yellow. The other wire on the front primary is light green. The other wire on the front secondary is light green/white. The other wire on the rear primary is light green/black. The other wire on the rear secondary is light green/red.

The water thermo sensor located on the rear of the water pump HOUSING, is green/white and the other pure black (possibly brown/black).

I seriously doubt your car runs with the green/white wire on a fuel injector.

 

See pic...

Peel back the plastic harness insulation and those wires *have* to be there somewhere, even if the plug is MIA for some ungodly reason. Good luck.

 

After looking at the wiring diagram, it looks like it's not the one that matches my car. I have a 87 GXL N/A, and that wiring diagram looked like one for a TII, and so did the one that was in the FAQ it looked like. None of the wires on my harness where black/yellow for the fuel injectors. Also, there's only really 1 way you can hook the injectors up. Since the wires are all different lengths, they really only plug in 1 way, otherwise you have a bunch of slack in the wires or the wire is too short. Also, the car wouldn't run hardly at all if the injectors were plugged in wrong. The only wires that I have cut on that part of the harness are the 6 that went to the vacuum solenoids that were on the vacuum rack that I removed. I haven't seen a green/white wire or a brown/black wire on that part of the harness for the thermo sensor yet, and I know it's not been cut off otherwise I'd have found it by now. The only plugins that I've found so far are a little square black one for what seems to be the optional e-fan, a 3 wire black connector with 2 spade terminals in it, and a 2 wire white connector with 2 spade terminals in it. Other than that there are the 6 wires for the fuel injectors, 1 wire for the O2 sensor, 3 wires for the TPS, 2 wires for the AIT sensor, and 2 wires for the alternator plug-in. I see no other wires than those on the harness.

 

if you cant find the wires you can look up the ECU pin out and run your own wires from the ecu to the water thermosensor

 

My bad. I was thinking 88 car. The black/yellow does not exist on any of the early 87 cars. BUT the other wires I listed are correct. So if you look at the injector plugs you can figure out which injector is which just by looking at those wires.

Later when time allows, I'll give the wire colors for each of the two wires on the injectors.

I guarantee green/white is NOT an injector wire color.

 

Go here: https://www.rx7club.com/forum/showth...ight=brown+red

I posted a picture of early series four injector wiring there.

 

I can assure you (and others can too) that the picture in post #15 is of a non-turbo 86-88 NA. The pins at the top of the diagram to to various solenoids not on a turbo (i.e. relief and port air solenoid valve). You definitely have something weird going on with your wiring. I'd abandon ship and follow post #17. Best of luck. Follow up and let us know what happens/happened.

 

*********not on a turbo (i.e. relief and port air solenoid valve). *******


??????????????????????????????????? Turbo's also have those.

The black and white connectors sound like the ones for the split air and port air solenoids.

Only six wires for fuel injectors?????????? Lets's see. Two times four is?????? So your missing two injectors wires also? By the way, the injector wire colors in that thread I attached above are a right as rain.

 

HAILERS - I messed up - yes - turbo's have those...

Here's a picture of the TurboII ECU Wiring, for reference. You will see a knock sensor, a dead giveaway.

 

Thanks Hailers. I'm going to check over the wiring in that area and make sure everything is right. I'm probably going to trace back to the ECU and look for the wires there for the thermo sensor. What are the split air or port air solenoids?

 

Split air and port air solenoids are screwed into the ACV. They have *pigtail* harness on them that connect to the white and black plugs you mentioned.

The water thermo sensors green/white wire in the middle plug on the ECU, pin 2I. Top row and about the fifth wire over from the far right of the middle plug.

If the water thermo sensor is not connected up, the ECU defaults the value for the sensor at 176*F. So the car will run almost normal except on cold engine starts the start will be harder because the fuel injected during a cold engine start will be smaller than it normally would be. So that would be the major disadvantage of the sensor not being connected.

 

Alright, if they were for the ACV then I'm going to remove them from the harness. I have the ACV and split air pipe removed. I'll take a picture of them and post it just to make sure that's what they were for.

That would explain why the car didn't start as easy last winter. Hopefully I can trace this down before winter hits again.

Thanks for the info on the thermo sensor. Time to get to work.

 

Good news. I found the thermo sensor wires. They ended up being near the primary fuel rail wires. I completely tore that part of the harness apart all the way to the wire wall and decided to re-wire the harness to compensate for all of the other sensors, solenoids, emissions equipment, and other things I've removed. That wiring diagram was the correct one. I've got the low impedence injector harness, so those colors matched correctly. The only gripe I've got about Mazda's harness configuration was attaching all the grounds together inside the electrical tape and wiring loom. I've decided to make seperate grounds for each of the sensors that require a ground. After I'm done, I'll take pictures so you guys can see how I did things. My only other question for now is this - the blue wires in that harness were for the vacuum solenoids near the CAS correct?