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Oil Pressure Gauge "Dances" Low When Stopped


Dabblingman

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Vehicle Year
1999
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Ford Ranger (V6
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Hey! A week into our 1999 3.0 V6 Ford Ranger. Much to learn. Many quirks.

Today, noticed that the oil pressure gauge is normal (in the middle) when....
1) Driving (moving)
2) In Neutral
3) In Park

BUT, when in DRIVE, but stopped, the needle on the gauge drops to the low side and bounces up and down on it. A special "Check Gage" (they, that's how it's spelled) light comes on. Once I drive away (from the stop light, etc), everything is OK.

Anyone ever see this? Any ideas? Thanks in advance!
 


franklin2

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Bronco II
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I would assume Ford was consistent with this, my 1989 f250 has a fake gauge. Instead of a sensor out on the engine to send back oil pressure readings, they just installed a switch and put a resistor on the cluster circuit board. If you have over 5 pounds of pressure, the switch opens and the resistor is hooked in so the guage reads straight up in the middle.

If you get less than 5 pounds oil pressure, the switch will close, grounding out the gauge wire and making the gauge go to zero.

Your best next move is to go to the store and buy a real pressure gauge, one of the cheaper ones with the tubing will work. Hook it up and see what pressure you are really running. if it really is going up and down on either side of 5 pounds, if you went to a little thicker oil it may make the problem go away. Needless to say if this works you have some wear in the engine, but you might be able to work with it. A new pressure switch may help it also. But see what pressure you really have with a real gauge.
 

pjtoledo

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my 2000 has been doing that on and off for at least 15 years.
I usually put 10-30 or 15-40 oil in for the summer, 5-30 in winter.
that helps, but does not totally eliminate the issue.
 

tinman_72

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Ford
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Factory
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None
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255/60R15
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When you have the factory "fake" gauge, the sending unit has a single wire connection. It is a male prong sticking out and the wire is a female piece that goes on. This can get dirty and cause a weak connection resulting in the gauge intermittently or permanently showing low. This is a very common scenario. The first thing I would do is clean that connection and see if the issue goes away. This is a free procedure.
You can convert the "fake" gauge to a real one by replacing the sending unit (do a Google search for the correct unit) and placing a jumper wire to bypass the resistor on the gauge cluster. If you want to see an actual number for oil pressure, pick up an aftermarket gauge like Franklin recommended.
 

fastpakr

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If you do end up pursuing an aftermarket gauge, this pod blends in almost completely on the A pillar:
1719249809674.png

You'll just need to find a matching trim paint color and give it a quick spray before installing.
 

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