Photo request - Oil temp sensor wire on a 1985 12A
 

OK, so I have this car that I accidentally destroyed some of the engine harness on - towed the car home without an engine and didn't secure the engine harness, so it dropped and dragged for like 200 miles! Hahah, yeah shoot me. The part of the harness that I killed contained literally the only connectors I needed from it.

Sob story over.

I've found where to send the oil level wire, coolant temp sensor wire, and oil pressure sensor wire. But I am having trouble with the oil temp sensor.

Request:

I think it's important that your car is actually an 85 (or maaaaybe an 84?) because there are some differences in dash gauge wire routing late in the FB production.

Can anybody with relatively intact stock engine wiring take a well lit photo of the left side, specifically where the oil temp sensor wires meet the harness? The sensor, if I am looking at the right thing, is in the oil pan below the spark plugs - it has a one-wire connector. If you could also pair it with a description of where the wires for that connector disappear into the larger harness, that would probably help me a lot with this wiring job.

Thanks in advance :)

I don't have a pic for you but you will find what you need in the 85 factory wiring diagram.

http://foxed.ca/rx7manual/manuals/19...g_Diagrams.pdf

I think that temp sender is for the sub zero starting system? So it is not a temp sensor that your see an indication from, it is a thermo switch to engage your cold start motor.
See page 50-10 of the PDF above.

The diagram will show you where it goes and what other connectors it interfaces with.

Is your cold start system even functional? I am not sure if WA will even be cold enough to trigger it?

I depinned most of that entire leg of the harness, all I run is oil press, coolant temp and oil level for dash indicator, if I recall correctly.

If you dont run emissions, hot start, cold start etc, there are very few actual wires for the engine/sensors. Makes for a clean engine bay.

The cold start system never operated correctly. There was a service bulletin from Mazda to disconnect the cold start pump motor. Unless you want a factory looking car, I'd just remove the cold start reservoir.

OK that solves a mystery then! In some other manual I have, that's labeled the oil temp sensor in a structural illustration. I was poring over that wiring diagram looking for something that was something else, lol. My car is going fully stripped minimal wiring. I did find the oil pressure, coolant temp, and oil level wires that go to the gauges through X-08 connector. So I think I am probably good on finding the wiring I need to find to wrap that up.

Awesome.

And one thing you can do is 'de-pin' the actual connector.

So for all the wiring you are deleting , use a small screw driver to pry up the pin in the connector body and pull out the whole wire you don't need.

You will end up with just a few wires left on the one side of the engine harness connector. Just gotta make sure you delete the right ones haha.

I found my old pic from how the harness ended up, after this just use some Summit Racing nylon overbraid. It comes in all various diameters.

https://www.summitracing.com/int/par...0340/overview/


https://cimg3.ibsrv.net/gimg/www.rx7...109178453a.jpg

I depinned one. There's one mystery wire that I left in and ran through the shrink tube. If I find what it is and I need it, cool. If I don't need it, I'll tuck/snip it.

Now I need to decide where to route it. It will reach the sensors if I run it across the back of the engine bay along the firewall or if I bring it up over the engine near the alternator where the factory loom gets routed. Maybe I'll decide when I see what hard lines I'm left with across the firewall.

https://cimg4.ibsrv.net/gimg/www.rx7...32437fbf25.png

This is what I removed:
https://cimg9.ibsrv.net/gimg/www.rx7...74a54e57a7.png

DIY oil pressure and oil level sensor connectors

Attachment 749038

The factory harness, as you know, runs to the oil pressure and water temp sensor under the oil pedestal. Then it goes down the back of the engine to the oil pan.

split mine off at the front iron where the AC/Power Steering bracket is. This way, I could run the oil pan connectors behind that braket out of site. It also saves them getting oil from the filter that always happens.

I am leaning toward up over the front of the engine past the alternator, barring any weird interference with the plug wires. The reasoning is that choke and check relay connection from the alternator goes through the same X-08 connector as the engine sensors and I'd prefer to split the loom in fewer places. We'll see how it goes.