'99 7.4L, what is this sensor?

I'm 99.44% sure this is an oil pressure sensor, but I'm not sure why it's here. This is right at front of the block on the left side, just behind the power steering pump. The FSM doesn't make any reference to it, and in the parts diagram this location is listed as "oil galley plug". The oil pressure should be coming from the "fuel pump oil pressure switch and sender", which is located at the rear of the block on the drivers side.

The wires for this sensor aren't in the factory loom, but don't look like a driveway hack. They're run along the same path of the loom, reasonably well dressed in. The wire on the connector is black/orange, and there's a grey wire that appears to be a ground (engine was hot, so I couldn't stick my hand too far down there ).

The only reason I really care is because it appears to be leaking from the body of the sensor, and I need to replace it. Seeing as how it's not referenced in the FSM, I'm not sure what I should be looking for to replace it.

Sorry for the less than ideal photo, can't get the camera to focus on just the sensor.

Thanks!

That would be the oil pressure sender

Dropped88 said:

That would be the oil pressure sender

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OK. But according to the factory service manual, oil pressure should be coming off the "fuel pump oil pressure switch and sender", which is located at the rear of the block on the drivers side. I did check both the '98 and '99 FSMs, and don't see it. I've seen other discrepancies, like the 7.4L having two knock sensors, but there's only one on this truck. Unless I'm just totally wrong, this is the early model '99. I guess I should hunt down a 2000 FSM and see what it shows.

Here's what I found in the 1998 manual, which seems to jibe with what you've said.




Here's the picture from the service manual of the 7.4. The item marked "4" is the item of interest.



Here's what the connector reportedly looks like:

this socket will make it easier to get it out

The oil pressure dash guage is run from the sensor back by the bell housing. They're not all 3 conductors, some are only one.....like mine. Unfortunately, I dont know what that is in the ops picture....looks like it behind the ps pump.

In my experience the small blocks are at back of block and the big blocks had it down low at front of engine

jcwren said:

I'm 99.44% sure this is an oil pressure sensor

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That's not the EVO connector and EVO assembly, mounted on the back of the PS pump, is it?

IIRC the EVO is two wires.

Piratehunter said:

this socket will make it easier to get it out

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If a 12-pt deep-well socket doesn't have enough reach, I suppose the Lisle socket might.

A box-end wrench should work, if one can get suitable access... which might be tough with the engine in the vehicle.

1998_K1500_Sub said:

If a 12-pt deep-well socket doesn't have enough reach, I suppose the Lisle socket might.

A box-end wrench should work, if one can get suitable access... which might be tough with the engine in the vehicle.

Click to expand...

The socket linked has the correct pattern to engage the sensor. It's not the same as a run of the mill 12 point sensor.