LPO Issue?

ToMang07

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So I replaced the LPOP with a Melling unit in Jan/Feb. Come March, I have a severe vibration I was attributing to a bad injector, I know the passenger front (#1 iirc) is running much cooler than the others when I put the IR gun on it.

Well I noticed the last couple times I started the truck to move it the Oil Pressure gauge keeps dipping to 0 after it warms up a little the soon as the truck hits low RPM or idles.

I'm lost, not sure whether to pull the LPOP and put a stock one back in, spun bearing, or injector related?

Forgive the heavy breathing, I'm all stuffed up and was running around trying to kill all the yellow jackets that apparently thought my truck was a neat place for a half dozen nests.

http://youtu.be/wMMM8wdkSoI

http://youtu.be/7IVIuGA0JL8

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CarportMechanic

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I had my oil pressure sensor go out on me a few weeks ago. It would read fine for a while then dip below normal and make the warning light come on. Read fine and then stop working again. Replaced the sensor and all good.

I was thinking it was the sensor due to my HPO was staying consistent. Are you loosing HPO?

Although I was not experiencing any vibrations or anything you may want to check that sensor out if it hasn't been replaced.
 

uncool

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Put a mechanical gauge on it and check your pressure. The dash gauge is more of a switch, above ~7 psi, all good on the dash.

Miles on the truck, injectors?
 

ToMang07

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Put a mechanical gauge on it and check your pressure. The dash gauge is more of a switch, above ~7 psi, all good on the dash.

Miles on the truck, injectors?

Guess I'll have to buy one. Port is on the side of the oil cooler, correct?
 

ToMang07

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I had my oil pressure sensor go out on me a few weeks ago. It would read fine for a while then dip below normal and make the warning light come on. Read fine and then stop working again. Replaced the sensor and all good.

I was thinking it was the sensor due to my HPO was staying consistent. Are you loosing HPO?

Although I was not experiencing any vibrations or anything you may want to check that sensor out if it hasn't been replaced.

I'll try it. Already drained the oil, new oil/filter tomorrow and a new sensor. Guess we'll see then.
 

ToMang07

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Well, no change with the new sensor and oil change. I'm not surprised, but I was hopeful it would work.

Next step I guess is find where to get a LPO gauge and which port to tap.
 

ToMang07

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I wonder if this could all be related to the melling LPOP? What are the odds that it's just out of spec enough to work but not get quite enough pressure? I mean it was fine for a month or two when it was very cold out. I could always swap the oem LPOP back in.

I cut the Oil filter open, didn't find a thing, not a spec of visible metal anywhere.
c7b4d82b62b5af966a2ece35387f484a.jpg


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ToMang07

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The bolts had basically loosened just enough that the pump seal failed, the OEM pump had no damage, I only put the melling in because I had already bought it.
 

ToMang07

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Well, got the valve cover off today and it was definitely the #1 cylinder.

However I wasn't even close and what the issue was, although it explains the LPO issue.

So anyone have any idea how much damage it probably did?

Pushrods are straight.
469445d51be6eac5714e1ef921525ccd.jpg


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Magnum PD

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Good question on damage. Idk myself.

But what does the rocker arms have to do with lpo?
 

Magnum PD

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Don't believe 2 lifters not working will cause no oil pressure.

Someone else might know, when the lifter is seated, does it fill with oil at that point?
 

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