[SOLVED] 2007 yukon 5.3 no oil pressure

[juicyroot]

Hi guys
I have a 2007 yukon 5.3 and my oil pressure gauge isn't working and I'm showing a CEL for it.
Like 8 months ago the gauge started registering low oil pressure and oil light started flashing ( no CEL) so I replaced the oil pressure sending unit located between fire wall and intake and it fixed the problem up until like a month ago and gauge started showing 0 oil pressure and doesn't move at all.
I have still been driving yukon with no issues so obviously its not oil pump or any other serious issue.
My question is what could it be this time? Oil pressure sending unit again or something else?
Like I mentioned the CEL never came on the first time, only oil light started flashing first time and pressure was very low but now 0 pressure and CEL with no flashing oil light.

 

[Fless]

I'm not very familiar with that particular year, but if the engine has AFM there will be a screen underneath the oil pressure sensor. If that wasn't replaced, or is clogged, the oil pressure sender won't report properly. YMMV

 

[West 1]

Some of the aftermarket Oil pressure senders are not very good quality. Could be just another failed unit? As Fless mentioned there is a screen under the OP sender that should be replaced. Some of the new OP senders come with that screen.

 

[juicyroot]

I'm not very familiar with that particular year, but if the engine has AFM there will be a screen underneath the oil pressure sensor. If that wasn't replaced, or is clogged, the oil pressure sender won't report properly. YMMV

I saw on YouTube a guy said he just removes that screen.
What do you think?

 

[Fless]

I'm sure there are positives and negatives, but I have no experience with either one.

 

[Foggy]

I saw on YouTube a guy said he just removes that screen.
What do you think?

Get a real ACDelco or GM oil pressure sensor with the screen..
Your CEL is telling you your current one is Bad. Check the wiring
while you are there
Yeah it's a PITA to do !
Make sure you get it from a reliable source. Lots of fakes on amazon, etc

 

[OBSandaNNBS]

Get a real ACDelco or GM oil pressure sensor with the screen..
Your CEL is telling you your current one is Bad. Check the wiring
while you are there
Yeah it's a PITA to do !
Make sure you get it from a reliable source. Lots of fakes on amazon, etc

This x100.
Pop a brand new screen in it. Use an OEM sensor every time.....

 

[swathdiver]

The screen is there to protect the AFM solenoids from debris. Modern GM engines do not take kindly to aftermarket sensors, neither do they seem to last these days either.

My daughter had to have some fancy 8mm red wires for her truck. They were causing misfires after about 40K miles so we put her old ones back on that had 120K on them already and the misfires went away.

Have you replaced the engine oil pump's pickup tube o-ring yet?

When replacing the oil pressure sensor, I find it easier to pull the intake. Takes a few more minutes but no busted knuckles and contortions to hurt my back.

 

[Charlie207]

When replacing the oil pressure sensor, I find it easier to pull the intake. Takes a few more minutes but no busted knuckles and contortions to hurt my back.

It's also a good time (if pulling the intake manifold) to check/replace the valve cover gaskets, VLOM bolts (they sometimes loosen up over time), and you were going to retorque the intake manifold bolts anyways, so it's not much more work.

 

[West 1]

I have heard loose VLOM bolts can lower your oil pressure. I have not seen that personally yet but it has certainly been reported as a possible cause of low oil pressure. My 08 6.2L with new Oring on the oil pump pick up and the factory oil pump at 145,000 miles has 60 PSI at anything over 1500 rpm but has just 20-25 hot idle oil pressure. I know something is loose inside, maybe the VLOM, maybe cam bearings but it runs great for now. I may pull the manifold and replace the VLOM gasket/plate. This engine sometimes has a misfire at idle, not constant, just once in a while it will miss a few beats. I have suspected an intake manifold vacuum leak so I may pull it and check one of these days. By all professional standards 20 PSI at hot idle is fine and will not affect engine life. AFM systems want to have hot idle OP at a minimum of 26 PSI if my memory is correct. Otherwise it won't engage. Personally I know tight engines will offer 40 psi at hot idle and I always shoot for that when I assemble an engine but there is not engineering backing up my personal choice. It just feels better to glance at the OP gauge and see solid OP even at hot idle. Probably wastes some gas pumping oil at higher pressure, I am fine with that as it is minimal.

 

[Joseph Garcia]

I have heard loose VLOM bolts can lower your oil pressure. I have not seen that personally yet but it has certainly been reported as a possible cause of low oil pressure. My 08 6.2L with new Oring on the oil pump pick up and the factory oil pump at 145,000 miles has 60 PSI at anything over 1500 rpm but has just 20-25 hot idle oil pressure. I know something is loose inside, maybe the VLOM, maybe cam bearings but it runs great for now. I may pull the manifold and replace the VLOM gasket/plate. This engine sometimes has a misfire at idle, not constant, just once in a while it will miss a few beats. I have suspected an intake manifold vacuum leak so I may pull it and check one of these days. By all professional standards 20 PSI at hot idle is fine and will not affect engine life. AFM systems want to have hot idle OP at a minimum of 26 PSI if my memory is correct. Otherwise it won't engage. Personally I know tight engines will offer 40 psi at hot idle and I always shoot for that when I assemble an engine but there is not engineering backing up my personal choice. It just feels better to glance at the OP gauge and see solid OP even at hot idle. Probably wastes some gas pumping oil at higher pressure, I am fine with that as it is minimal.

There is absolutely nothing wrong with a 20 psi hot oil idle pressure. In fact, Melling states in their instructions to expect a hot idle oil pressure in the neighborhood of 20 psi, after installing their pump.

I have the Melling high pressure/high volume oil pump with the +10 psi spring installed, and the oil pressure relief valve deleted, and I still get 20-25 psi hot idle oil pressure.

 

[juicyroot]

Ok as crazy as it sounds, I purchased a cheap $14 OIL Pressure Sensor from Amazon and installed it. (Previous Sensor was like $65 at Advance which only lasted a few months).Oil pressure gauge still didn't move so I shut the engine off and plugged my scanner in and deleted the CEL. Started the engine and OIL Pressure Gauge went up to 40ps and dropped to like 28 after warming up .