Mystery Low Oil Pressure

[TT/Ameasap]

My car typically has 60psi cold and 40psi hot idle. The other day, my hot idle was at 15psi and it barley went to 20-25psi when getting on the gas. So, I decided to change the oil and examine the old. The old oil looked typical without anything. I try to prime the motor (Orange plug unplugged) and the car with the new oil will not prime. So, I pulled the cam sensor and primed it to 20psi and put everything back together. Still no prime!
I pulled the pan and seen no material in the bottom.
Pulled the pump gears and there are no signs of rubbing or cracking...Or slipping.
Everything looks good from the bottom view of the motor. No in/out crankshaft play at all.
To recap..... Oil lost pressure(not ALL pressure) and I did an oil change and lost ALL prime.

Im going out to cut the old oil filter now, but I have a feeling there isnt going to be any material in there.
What else can I look for that would cause this?

EDIT:
Issue is fixed. Read below as to what I tried and what was suggested and you will find the answer to my problem

 

[TT/Ameasap]

Filter element is free of any bearing material as expected.
I pulled the oil spring and cup on the motor from the pump and didn't see any blockage.

EDIT:
This is what it was....Blockage from some foreign debris in the oil spring/cup galley.

 

[hotairgnx548]

Filter element is free of any bearing material as expected.
I pulled the oil spring and cup on the motor from the pump and didn't see any blockage.

TT/A why not pack the cavity with vasoline and try it. Maybe just lost prime. Good luck. Check gaskets while its apart. John

 

[BEATAV8]

check pickup tube and pickup tube gasket

 

[vacuum 6]

Plug the block for the turbo oil feed and re-prime.

 

[pacecarta]

look for a cracked gear on the oil pump gear with the shaft
popped galley plug in the block behind the cam gear

 

[TT/Ameasap]

I checked the oil pickup gasket and it seems to be fine. I blew some air up into it and didnt feel any air on the gaskets.
I checked for cracks in the gears as mentioned in the first post. I could not spin the gear on the shaft with all my might.
I repacked the gears with Vaseline and put the oil pan back on. Im gonna prime it until I see oil out the lifters this time.

 

[SHADOWII]

Praying the best for you, hopefully it's only the gauge!

 

[earlbrown]

Sounds like you might have been sucking air on the low pressure side like mentioned above. Check the pickup for a crack where it meets the flange, the gasket of course, and possibly the timing cover gasket where the inlet is.

 

[Lil Truck]

Is your gauge electric or mechanical? I would be checking pressure with new mechanical gauge.

 

[TT/Ameasap]

I primed it back up to 60psi and watched the lifters spew oil out....Now I have 25psi cold at idle. No ticking or any funny noises tho. Im gonna buy a gauge tomorrow and verify pressure.
Also, I unplugged the oil sensor and the car still fired up like normal.. Is that normal?

 

[earlbrown]

It is if the fuel pump relay is working. If that relay fails, the idiot light switch acts as a redundant backup.

 

[SHADOWII]

I primed it back up to 60psi and watched the lifters spew oil out....Now I have 25psi cold at idle. No ticking or any funny noises tho. Im gonna buy a gauge tomorrow and verify pressure.
Also, I unplugged the oil sensor and the car still fired up like normal.. Is that normal?

I'm going from memory on this , which can be suspect(!), on the stk ecu, less than 4#s of oil pressure and the eng. shouldn't start.

 

[earlbrown]

The oil pressure switch is NOT a kill switch, it's a redundant back up.


The pump gets power from two places, the oil pressure switch and the fuel pump relay. If one of them fail, the pump will get power from the other.



If the pressure switch becomes compromised, you'll lose the idiot light.

If the fuel pump relay fails, you'll have to crank the engine until you get 4PSI, then the engine will start.


The car will not kill the pump unless BOTH of those systems fail.

 

[TT/Ameasap]

Mechanical gauge reads 20psi just like inside the car. The psi rises with RMP and seems normal in that respect. I can get 60psi no problem. just idles at 20psi. Lemme know what you guys think. Im at a loss for ideas.

 

[Lil Truck]

My fresh motor has 55-60 psi cold start, at 165-170 it idles 850rpm at 25psi and rises at least 10psi per 1k. after a pass it idles 20psi at idle. 10/30 oil

40psi hot idle is abnormal unless you made some kind of modifications for high idle pressure? I would suspect that the sending unit gave you false readings until now?

 

[v6turbo87]

20 psi hot idle is not uncommon. If you have been using an electric oil pressure gauge it may have been lying to you all along and the sender has now gone bad.

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[turbo nasty]

Heck...12-15 PSI at hot idle isnt uncommon at all and is fine as well.

 

[TT/Ameasap]

No, somethings wrong guys. This motor has always had good pressure. I have a HV oil pump with 70psi spring. It is a Weber stroker longblock from 06. Im not going to just ignore a potential big problem. Theres over 10k in it.

 

[Lil Truck]

No, somethings wrong guys. This motor has always had good pressure. I have a HV oil pump with 70psi spring. It is a Weber stroker longblock from 06. Im not going to just ignore a potential big problem. Theres over 10k in it.

Did not know you had that much time on it. Hope it is nothing to serious!