Floodx4

I just got my EJ253 back together from a full rebuild, and I am down to the Coolant Temp Sensor and what I believe is the oil pressure sensor. My builder installed a "new" main harness, and all connections matched up, except the temp sensors. What I can see from looking at my old harness compared to the new, is that my old harness clips have black centers, and only the 2 main pins. The plugs on the new harness, have yellow centers, and what looks like a very small 3rd pin in the middle, above the two main pins.

My questions are ...
(a) is this harness OK, as it is obviously not the same as the original? (engine is not installed, so I have not tried the main connection).
(b) what year is this harness from?
(c) assuming a and b are known, can I just get the correct

Oil pressure (?) sensor plug
sensors, or should I splice the old plugs on the new harness, and use the proper, original temp sensors?

I am sorry if this isn't enough information. I can get pics tomorrow if needed. The engine is wrapped up on the stand in my shop right now.

Car is a 2008 Impreza 2.5i, engine rebuilt back to stock.


Temp sensor plug

**EDIT. I did find the pics mu builder sent me of the "new" plugs.

Don Clark

For a turbo'd engine the coolant temp sensor looks correct (triangular 3 pin) but for a N/A engine it is not.
As far as I can tell the same temp sensor is used for both the oil and coolant.

Floodx4

@Don Clark
OK. That would make sense as the builder I used does not normally do N/A engines. In fact, he said he could not remember the last time he had built one. He was only supposed to build me a long block, but he ran into some issues (COVID), and it took longer than expected, so he tried to help me out by giving me a "turn-key" build.

So, would I be better off trying to match the sensor to the harness, or swap the plugs and use the proper sensors? Or, am I going to run into other issues, and would be better off just putting my original harness on the engine?

Don Clark

Use the correct sensor.