LLY: Oil Pressure reading w/ EFILive

[jmg343]

On a drive down to South Jersey last weekend I noticed that my oil pressure gauge was pegged well past 120. The truck was running fine and oil level was normal. I figured the gauge went crazy.

I changed my oil on Tuesday and the gauge returned to normal. Most likely coincidence.

Today the gauge was operating normally and reading normally. But, I hooked up EFILive just to see what it said my pressure was. According to EFILive my oil pressure was 2.2 PSI at idle. While driving between 20% and 100% throttle the oil pressure hovered around 4.7 PSI never going over 6.6 PSI. This seems awfully low, no? Which reading should I trust? The dash gauge or EFI? And if my oil pressure were that low wouldnt it set a CEL?

What would be the causes of low oil pressure?

The truck was and is running as good as ever.

 

[jmg343]

Also, why does EFI Live show Turbo Boost Pressure as ~16PSI at 30% throttle when my in cab boost gauge is showing 3-5 lbs? At 100% throttle EFI says 42lbs, my gauge says 32-35.

 

[sweetdiesel]

Also, why does EFI Live show Turbo Boost Pressure as ~16PSI at 30% throttle when my in cab boost gauge is showing 3-5 lbs? At 100% throttle EFI says 42lbs, my gauge says 32-35.

It's adding baro pressure

 

[sweetdiesel]

Yes it should set a CEl

Not sure why it would show that low?

I would hook up a manual press gauge to see exactly what oil psi is

On a drive down to South Jersey last weekend I noticed that my oil pressure gauge was pegged well past 120. The truck was running fine and oil level was normal. I figured the gauge went crazy.

I changed my oil on Tuesday and the gauge returned to normal. Most likely coincidence.

Today the gauge was operating normally and reading normally. But, I hooked up EFILive just to see what it said my pressure was. According to EFILive my oil pressure was 2.2 PSI at idle. While driving between 20% and 100% throttle the oil pressure hovered around 4.7 PSI never going over 6.6 PSI. This seems awfully low, no? Which reading should I trust? The dash gauge or EFI? And if my oil pressure were that low wouldnt it set a CEL?

What would be the causes of low oil pressure?

The truck was and is running as good as ever.

 

[JoshH]

Are you sure you were looking at oil pressure and not oil pressure sensor voltage?

 

[jmg343]

Yep. ENGOILP...Engine Oil Pressure

parameter - GM.ENGOILP
system - conditions

 

[jmg343]

What would the causes of low oil pressure be?

Symptoms?

 

[sweetdiesel]

You need to verify if that's correct first


The nut can come loose on the oil pump gear and stop spinning the pump

 

[whytry]

Engine would be toast by now ....listen to sweet diesel put mech gauge on

 

[jmg343]

Id like to put a mech gauge on it. But, to be 100% honest, I dont have one, nor would I know where to put it if I did. Every mod to my truck Ive done myself, other than building my trans, but Im don't claim to be too knowledgable when it comes to our trucks. I can do just about anything to them after being shown how once, but I need a teacher for the first go round, or very detailed instruction w/ pictures.

 

[TIMTHECARMAN2004]

The turbo boost is reading that because it is taking baro pressure and adding map pressure. Sounds like your around 13 to 14 psi baro and then a few pounds of boost. The dash may have a problem but if pressure is too low the light and check oil would come on IIRC. There are little ports on the side of the engine block and I think one on the oil cooler. That would be a great place to test pressure. I will take some pictures tomorrow and post them for you unless someone else has some pics now...

Tim

 

[jmg343]

Thanks Tim. Can I pick up a mechanical oil pressure gauge at Napa? I cant imagine they are terribly expensive and probably come with hose, etc, no?

How difficult is it to get to the oil pump gear? Can you get in there and re-torge the nut without pulling half the motor apart?

 

[kjp800]

If you are in south jersey I have a gauge you can borrow, or can give you a hand checking it. Like was mentioned already, if oil pressure was that low you would have a CEL and warning message. I had a similar problem and it didn't run too long with the low/no oil pressure, but it wouldnt hurt and would be good piece of mind to check it anyways.

 

[sweetdiesel]

Thanks Tim. Can I pick up a mechanical oil pressure gauge at Napa? I cant imagine they are terribly expensive and probably come with hose, etc, no?

How difficult is it to get to the oil pump gear? Can you get in there and re-torge the nut without pulling half the motor apart?

Motor would pretty much have to come out to get the front cover off

Gauge would probably cost you 20 bucks just for simple testing I would go into the oil gallery even with a metric barb fitting it shouldn't be more than 30 bucks for the gauge fitting and hose clamps

I would opt for a 0-100 psi liquid filled gauge


Iirc it's 12 mm x 1.5 but it's posted on the site under oil gallery thread pitch.... So make sure I'm right