Inaccurate oil pressure gage

ScottiGotti1807

ScottiGotti1807

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Joined
Jul 22, 2020
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27
Location
Rye Colorado
Hey guys. Just bought this 02 Tj. Has the 4L straight in her. The oil cap is dead center and plastic. Is this engine the Dana 44 or the other one?? Second question is. The guy I got the Jeep from. Said the oil gauge is pegged not sure why. He has changed the sensor out twice one time with a Mopar. And the other he wasn’t sure. But he also has tested the oil pressure manually and it is around 30 or 40. The guy seems pretty trust worthy. But was wondering if the best solution for this would be to just wire a fresh a gauge in or screw around with the wire harnes and all that. Let me know what u guys think.
thaks to all
Scott
 
ScottiGotti1807 said:
... Is this engine the Dana 44 or the other one?? ...
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What?

Do you mean is the rear differential a Dana 44 or the Dana 35?

Jeep Diffs.png
 
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Newer TJ oil pressure gauge indicators were reprogrammed to stay centered so long as the true underlying oil pressure is normal. That was done because too many new TJ owners complained their oil pressure kept going up & down and they didn't believe it when their dealers tried to explain it was normal and supposed to do that.
 
ScottiGotti1807 said:
Ok do I have to pull the whole dash apart?!? Or where should I start tracing the wire
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Looking at the sensor you can see that 5 volts and ground are supplied to the sensor from the PCM. As the sensor senses oil pressure it changes the output voltage and sends that voltage to the PCM as a sensor signal.

I would first disconnect the sensor and see it the gauge still pegs with the key on. If it DOES NOT I would replace the sensor. If it does, I would use a voltmeter and put the (+)lead on pin 1 (violet/orange wire) of the sensor's pigtail and the (-)lead on pin 3 (black/light blue wire) of the sensor's pigtail. Then turn on the key and see if you have 5 volts on the meter. If you DON'T have 5 volts I would then remove connectors C1 and C2 of the PCM and measure continuity like this and see what you get:

Sensor pin 1 ——- PCM C2-B31
Sensor pin 2 ——- PCM C2-B23
Sensor pin 3 ——- PCM C1-A4


sensor.jpg
 
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ScottiGotti1807 said:
Yes I did from a guy in highland ranch. You know him.
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Not personally. If it is the jeep I am thinking of though it is built pretty well.

The front axle is most likely a dana 30. Or a high pinion dana 30. The rear axle, if out of a ford, is an 8.8. Gearing would be 4.56.
 
tworley said:
Not personally. If it is the jeep I am thinking of though it is built pretty well.

The front axle is most likely a dana 30. Or a high pinion dana 30. The rear axle, if out of a ford, is an 8.8. Gearing would be 4.56.
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Not sure if it’s a high pinion Dana. But ya the guy did a hell of a job on the suspension. I Cruze 75 down 25 with one hand on the wheel and a foot probed up chillin.

I just picked up the Jeep about a week ago. So starting to get the feel for her. And fix minor stuff he didn’t get to. But he told me a guy up in Thornton did a lot of work for him on it.
 
ScottiGotti1807 said:
hey coda I diconected that that and the gauge still pegged. I checked volts between the orange and blk/lb and I have 5.04 volts. Any more ideas.
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Check continuity between Sensor pin 2 ——- PCM C2-B23

If that wire is good, I would clean and reseat the PCM connectors along with the dash cluster. If that doesn't fix it you most likely have either a bad PCM or cluster. At that point I think I would install a different oil sending unit and gauge mounted on the center console before I paid to replace either of those items.
 
ScottiGotti1807 said:
hey coda I diconected that that and the gauge still pegged. I checked volts between the orange and blk/lb and I have 5.04 volts. Any more ideas.
Click to expand...

also, I'm sure the PCM could give different indications depending on how the sensor has failed. I would also take my OHM meter and look for continuity on the sensor itself between pins 1 and 2 and between pins 1 and 3. If either of those read open (no continuity) the sensor would be bad.
 
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CodaMan said:
Check continuity between Sensor pin 2 ——- PCM C2-B23

If that wire is good, I would clean and reseat the PCM connectors along with the dash cluster. If that doesn't fix it you most likely have either a bad PCM or cluster. At that point I think I would install a different oil sending unit and gauge mounted on the center console before I paid to replace either of those items.
Click to expand...

cool thanks man that’s what I’ll do then.
 
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