Having low oil pressure after AFM delete in a 5.3 LH6.
#61
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iTrader: (2)
People that question the o ring are usually trying to dive too deep to find a problem.
The o ring matches the pickup tube and normally is matched by color or thickness of the o ring. If you had the wrong one itll show bubbles in oil likely.
It happens most of the time for no reason thats why we like to shim our ported pumps either rpmspeed or gm ls6.
The o ring matches the pickup tube and normally is matched by color or thickness of the o ring. If you had the wrong one itll show bubbles in oil likely.
It happens most of the time for no reason thats why we like to shim our ported pumps either rpmspeed or gm ls6.
#65
TECH Senior Member
#67
TECH Senior Member
No, because the oil relief piston only relieves when max pressure is achieved. It puts a lid on the max pressure. At idle speed, the piston is not even being moved. you have a different issue.
#73
#75
I am having the same problem. I changed the sending unit and small filter under it, oil pump pick up o-ring, and the oil pump itself - and the electronic gauge acted the same every time....
I did ALL of this assuming that the gauge reading in my dash was giving me the right reading.
I now have hooked up a mechanical gauge to the system and it reads 50psi cold, and 45psi hot. When I rev it up, the pressure goes to 55psi and holds there....ALL this from the mechanical gauge, (probably should have done that long ago)
I believe the electronic gauge in the dash is screwed up....Any opinions on that?
Did you verify the ACTUAL oil pressure with a mechanical gauge?
I did ALL of this assuming that the gauge reading in my dash was giving me the right reading.
I now have hooked up a mechanical gauge to the system and it reads 50psi cold, and 45psi hot. When I rev it up, the pressure goes to 55psi and holds there....ALL this from the mechanical gauge, (probably should have done that long ago)
I believe the electronic gauge in the dash is screwed up....Any opinions on that?
Did you verify the ACTUAL oil pressure with a mechanical gauge?
#76
I did verify with a mechanical gauge, it reads identical to the dash and my scan tool. My next step is pull the lifter valley cover, inspect, and plug the AFM lifter towers while I'm in there. Plugs are on their way. If that doesn't fix it, then............
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tjoyce81 (06-28-2019)
#77
In reading your posts closer - I noticed that you were unaware of the different O-rings that go on the oil pick up tube at the pump.
Make sure you have the right one in there. In 2007 the O-ring is usually the thicker one. red/orange or green.. NOT black or blue..That O-ring is also sized for the tube NOT the pump.
In looking at the way the the oil flows from the pump to the towers, I am not sure that plugging them will help you, because the AFM/DOD is already deleted - so the
solenoids do not allow oil to flow through them...
The oil pump pressure can be changed by either shimming the spring under the relief plunger - or putting a stiffer spring in there. VERY easily done - you only need an 8mm allen wrench to access the spring and plunger..
Also, fyi, the factory service manual says that the minimum oil pressure for your engine is 6psi @ 1000rpm... 18psi @ 2000rpm... and 24psi @ 4000rpm...
They bare the minimum numbers - so if you have 12 @ idle (usually less than 1000rpm) you may be ok with the pressure you have?
Hope you fix it....good luck...
Make sure you have the right one in there. In 2007 the O-ring is usually the thicker one. red/orange or green.. NOT black or blue..That O-ring is also sized for the tube NOT the pump.
In looking at the way the the oil flows from the pump to the towers, I am not sure that plugging them will help you, because the AFM/DOD is already deleted - so the
solenoids do not allow oil to flow through them...
The oil pump pressure can be changed by either shimming the spring under the relief plunger - or putting a stiffer spring in there. VERY easily done - you only need an 8mm allen wrench to access the spring and plunger..
Also, fyi, the factory service manual says that the minimum oil pressure for your engine is 6psi @ 1000rpm... 18psi @ 2000rpm... and 24psi @ 4000rpm...
They bare the minimum numbers - so if you have 12 @ idle (usually less than 1000rpm) you may be ok with the pressure you have?
Hope you fix it....good luck...
Last edited by tjoyce81; 06-29-2019 at 12:27 AM.
#78
TECH Senior Member
On the oil tube O-ring, if there is a groove rolled in the tube near the end that goes in the pump, it uses the thicker O-ring. No groove, the thinner one.
#79
I pulled the pump and pickup tube, I did have the wrong o-ring on the tube. Replaced with the red one. Inspected pump internals and relief. Reassembled and no change in oil pressure. The only thing left to do is plug the towers. I shouldn't have to plug the towers, but I'm out of ideas on what could be causing the issue. Others have seen issues with the towers, plus it can't hurt to plug them. I realize that I'm above minimum oil pressure recommendations, but it was much better before. I'd like to have the pressure where it was before. Thanks to everyone for their input.
#80
I pulled the pump and pickup tube, I did have the wrong o-ring on the tube. Replaced with the red one. Inspected pump internals and relief. Reassembled and no change in oil pressure. The only thing left to do is plug the towers. I shouldn't have to plug the towers, but I'm out of ideas on what could be causing the issue. Others have seen issues with the towers, plus it can't hurt to plug them. I realize that I'm above minimum oil pressure recommendations, but it was much better before. I'd like to have the pressure where it was before. Thanks to everyone for their input.
The following users liked this post:
G Atsma (05-08-2020)