(HELP) Engine Wire Identify 1990

[cabbageroll]

Recently took my engine out to replace engine mount and fix oil leaks. Also did clutch. Not sure where this wire go. Can't seem to remember where it went. Thanks for reading, any comment is welcome. There is 2 things I will add that may help identify. My temp gauge is not working and car idles @ 1.8k RPM.

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[m00se]

Should be the engine temp sensor on the back of the engine

[druz]

The coolant temp sensor connector at the rear is a green square. The gauge sender is a black spade.

What colors are the wires?

[—atank—]

Is this the connection? Its located under the TB.

[— kung fu jesus —]

Idle Speed Control Valve. It is the funky looking thing bolted to the bottom of a 1.6 throttle body with the coolant lines and J-shaped airtube.

When it is unplugged the ECU defaults the idle to 1800 rpms.

[cabbageroll]

Thanks kunfu jesus, i'm sure you're right. I'll check it out tomorrow. Thanks everyone else who reply too.

[cabbageroll]

So I found the place where it was located. My brother was the one who put the engine in. He put another wire at that spot so we just switch the lose wire shown and the idle is back to normal. My next problem is the oil pressure. It sits at the 1/4 mark and as I press gas or shift gear it goes up to 3/4 and back down if I de accelerate. My temp sensor not working too but im not worry about it since my I have my fans on all the time.

[— kung fu jesus —]

Oil pressure rises and falls corresponding with engine speed (RPMs).

The oil pressure sensor in on the side of the block, near the oil filter, under the intake manifold.

The coolant temp sensor is the green plug at the back of the head, closer to the driver's side. One of the heater hoses connects to the head near it. The fans are switched by the sensor with the grey connector on top of the thermostat housing that sticks out the front of the engine, near the cam sprockets.

If the coolant temp sensor is disconnected, the ECU should throw a CEL as it uses that sensor's reading to manage the fuel. If your temp sensor is connected and no code is present, and your temp gauge doesn't register, it may be a different issue.

[cabbageroll]

Thanks for the feedback ill check it out.