Now what? Oil pressure came back.

adam g

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About a month ago I started the truck, and the factory oil pressure gauge never came up. I shut it off and checked the oil level. It was fine. I started it again, no op. I ASSumed a rat had chewed the wire, thought I saw no evidence. I dropped the trailer and started loading saws to go cut wood. It started to idle rough and clatter. I shut it down. It's an 88 f250 7.3 probably has 150xxx on the engine.
I have spent the last month fixing the 4 other vehicles ahead of it, and cleaning out the shop. I pulled the truck in tonight. Oil pressure came up in 30 seconds. It did miss for a minute. Then it smothed out. I pulled the filter and ran it through a blue towel. No shiny. I plan to have the filter cut open tomorrow. I do have a rodent nest in the valley pan. I also have a fuel leak on the return. I wonder if that's the misfire. If there is no shavings in the filter do I change oil and run it? I am putting another gauge on it. I am nervous about it.
 

Nero

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My dad's crew cab did that a handful of times. No idea what caused it.
I even did a road call for him where I showed up with test tools on the side of the road to monitor pressure when he fired it up. Both my Guage and the dash showed pressure.

Installed an aftermarket oil pressure gauge so we can see the actual pressure, hasn't done it since then. So I'm chalking it up to wiring. Both the aftermarket and oem sensors are installed working in tandem.
 

Austin86250

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I don’t think you actually had no oil pressure you’d know it will KNOCK, rats eating wire is a high possibility, as your rough idle/ miss I believe that to be fuel related not oil pressure related
2 separate issues
 

CDX825

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Install and after market gauge with an actual read out. The factory gauges on these trucks are just glorified idiot lights. So long as there is 7 psi of oil pressure they will read "Normal"
 

adam g

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Install and after market gauge with an actual read out. The factory gauges on these trucks are just glorified idiot lights. So long as there is 7 psi of oil pressure they will read "Normal"
That is my plan.
 

Jesus Freak

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I'll just add, that if it sat for a looooonnñng time, there could be a layer of sludge in the bottom of the oil pan. It's not totally uncommon here in the subtropics of majestic NW Florida.
The sludge will even be in there after an oil change.
 
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adam g

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I'll just add, that if it sat for a looooonnñng time, there could be a layer of sludge in the bottom of the oil pan. It's not totally uncommon here in the subtropics of majestic NW Florida.
The sludge will even be in there after an oil change.
Just a few days.
 

adam g

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The oil filter is clean. Going to put it back together Saturday and run it.
 

turbokinetic

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I'm not an expert on these engines but want to relay my experience. This was newer 7.3 which is not IDI; however I expect the oil pump may be of similar design. It had the same "idiot gauge" which has only two positions, 0 and "normal" and does not actually read pressure.

The truck would often show no oil pressure on startup, and took anywhere from 10 to 30 seconds to build pressure. If I lightly raised the RPM of the engine, it would cause the oil pressure to come up more rapidly than just running low idle.

In the end, it ended up being worn parts inside the oil pump after 300,000 miles. It could not lift the oil from the pan and became air-bound very easily due to the excess clearance between the inner and outer rotors of the pump.

If the problem comes back, try gently raising the engine RPM at startup to see if it restores the oil pressure. That worked for mine for several months until I was able to replace the oil pump rotors.

Sincerely,
David
 

ISPKI

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I have had 3 trucks now where the oil pressure gauge would seem to stick initially. Even my current truck does it sometimes. Shows no oil pressure unless I tap on the dash above the gauge cluster once or twice. Give it a light smack and the needle pops right up and moves around freely after that. Usually does it on its own shortly after bouncing around a bit pulling out of my yard. After 30 years of bouncing around and dust and grime getting into the dash, I imagine the needle could have a little spot at rest where it might get stuck need some help popping loose.

Either way, an aftermarket mechanical gauge is the way to go.
 
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