Having an issue after swapping in used engine.

Eh-ef-kay

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May 3, 2021
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So I posted a few different places but figured since this one is more directed at these motors maybe somebody here will have some knowledge. Long story short I have a 2007.5 LMM fully deleted. The motor had some piston issues so I got a motor from an ambulance van lmm with under 100,000. Everything was swapped over by the mechanic that needed to be change such as the intake engine mounts harness stuff and what not. The problem is nobody can get it to run since it’s been installed. The tech to as well as a manual gauge is saying zero oil pressure. They pull the oil pan didn’t find anything unusual except the oil didn’t make it to the filter or anything. The oil pump was checked after removing the front cover and everything seems perfectly fine. In fact the oil pump and sending unit both look new. I’m basically looking for some suggestions or knowledge on what the problem could be. This truck has been down since December no one seems to be able to figure out what’s going on with it and I’m starting to think it’s done for. Someone told me that they believe the system needed to be primed but it was a used motor. Like I said at this point I’m looking for any type of input as to why a motor would not run that ran one pulled. I appreciate any and all responses
 

Leadfoot

Needs Bigger Tires!
Dec 27, 2006
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Western MA
www.matpa.org
Where did you get the used motor from? Did you change the oil/filter? How many times and for how long have you been cranking? Even a "dry" motor with enough oil should build some pressure after extended cranking (you said it's been since December so I would think that would count). Change the filter (maybe a defective/blocked one...) and if it doesn't build pressure on a manual gauge I'd say the oil pump is toast, it was messed with before you got it (like unbolting the pickup tube), or something happened during the swapover. Only so much we can diagnose via keyboard especially since you said the tech 2 and manual gauge are showing zero pressure.
 

Eh-ef-kay

New member
May 3, 2021
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Where did you get the used motor from? Did you change the oil/filter? How many times and for how long have you been cranking? Even a "dry" motor with enough oil should build some pressure after extended cranking (you said it's been since December so I would think that would count). Change the filter (maybe a defective/blocked one...) and if it doesn't build pressure on a manual gauge I'd say the oil pump is toast, it was messed with before you got it (like unbolting the pickup tube), or something happened during the swapover. Only so much we can diagnose via keyboard especially since you said the tech 2 and manual gauge are showing zero pressure.
Yeah this happened in December I bought the motor towards the end of December it took him two months to even get started on it it sat for that long motor and all. I have tried another filter already. Somebody was already in the bottom of the motor there were signs that somebody’s ziz wheeled it to clean off the old seal. pick up tube look fine. So they immediately thought oil pump. After pulling the cover the oil pump looks brand new there’s no shavings anywhere in the lower pan. The nut and everything looks nice and tight. I bought the motor at a yard. It was out of an ambulance van. They had videos of the motor running in the van and all that. It was pulled and I picked it up the same week it was pulled out. It sat for two months after that. There was a quart of oil in it when we drained it all out which was confusing usually junkyards completely empty motors. Basically everything is showing no oil pressure and it doesn’t appear to me like the shop knows what to do with this point they just keep telling me it Hass to be a bad motor. Which obviously I highly doubt. They even went the extra aggravation of pulling aside cover off of my old motor thinking a check valve was bad. I’m definitely just trying to get this figured out anything you might ask I probably can get an answer from them and get back to you with.
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
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Phoenix Az
i would be checking that all the o-rings and gaskets are in place on the pick up and oil pump. id also make sure all the oil galley plugs are in place. if a gasket/oring is missing, its going to pull air and not oil
 

Eh-ef-kay

New member
May 3, 2021
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OK so the front cover off spun the bolt on the oil pump with an air gun oil pressure rose up to 40 without any issues. So I’m going to gather that it’s losing pressure somewhere else
 

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