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1 Ton Dakota
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Discussion Starter · #1 ·
Pops got a 1999 Dakota 318 5-spd with 200,000+ miles. His oil light will ping and show zero pressure on the gauge. However, the motor still maintains power and runs fine. Any ideas?

Thanks
 

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A while back ago I took some notes from another Dakota site from a reply a trusted member had provided from his FSM. To condense what is applicable to your dad's issue: the needle on the gauge is controlled by the PCM according to the following schedule:
Oil pressure between 1psi & 20 psi the needle will show on the "lower end of the normal scale."
Oil pressure below 1 PSI the needle will move to "LOW" mark.

I remember in the old days (the '70s) when some cars just had an idiot light to indicate low oil pressure, I was told that the light wouldn't illuminate until the oil pressure dropped to about 2 psi. Meaning, to me, that an engine can operate with some pretty low oil pressure going on. However, I am thinking that an oil pressure of 0 psi (meaning NO oil pressure) would lead to a catastrophic failure in a relatively short order. Making me think that the reading your dad is getting is an error, meaning, to me, that either the sensor is malfunctioning or the PCM is malfunctioning or there may be a problem in the wiring in between the two.

I am thinking that the oil pressure sensor would be the easiest place to start -- I have read of them failing.
 

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1 Ton Dakota
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893 Posts
Discussion Starter · #5 ·
A while back ago I took some notes from another Dakota site from a reply a trusted member had provided from his FSM. To condense what is applicable to your dad's issue: the needle on the gauge is controlled by the PCM according to the following schedule:
Oil pressure between 1psi & 20 psi the needle will show on the "lower end of the normal scale."
Oil pressure below 1 PSI the needle will move to "LOW" mark.

I remember in the old days (the '70s) when some cars just had an idiot light to indicate low oil pressure, I was told that the light wouldn't illuminate until the oil pressure dropped to about 2 psi. Meaning, to me, that an engine can operate with some pretty low oil pressure going on. However, I am thinking that an oil pressure of 0 psi (meaning NO oil pressure) would lead to a catastrophic failure in a relatively short order. Making me think that the reading your dad is getting is an error, meaning, to me, that either the sensor is malfunctioning or the PCM is malfunctioning or there may be a problem in the wiring in between the two.

I am thinking that the oil pressure sensor would be the easiest place to start -- I have read of them failing.
I finally had time to change the oil pressure sending switch. Hopefully that fixes it. About two months ago, we replaced his PCM. It was still showing no pressure even with the new PCM. Its gotta be the oil pressure sending switch. Ill keep you up to date.

Thanks for the help BTW. Every helpful! Hopefully I don't get phone calls from my Dad b*tching about it anymore. Haha
 

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1 Ton Dakota
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893 Posts
Discussion Starter · #6 ·
@immattj Damn, it went off once already. He drove it for literally 30 minutes. Any other ideas what it could be?
 

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C'mon Dodge - NEW DAKOTA
2003 Dakota Club Cab Sport 4.7L
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485 Posts
I'd quit guessing, hook up a pressure gauge, and go driving.
 
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I'd quit guessing, hook up a pressure gauge, and go driving.
Yeah, I guess that would be the next step.
But here's the thing, it's a 22 year old truck with 200k on it, so if you discover that you truly aren't making oil pressure (which I doubt) how far are you going to go to save it?
But, as Radioactive said, putting a direct reading gauge on it will solve the mystery.

I am personally inclined to, think, at this point, that there must be a shorted wire either between the sender & PCM or the PCM & gauge.
 
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