Oil Pressure PSI?

[Yellow Cake Kid]

Hi,
I am wondering what sort of temporary high pressure PSI numbers people see when pushing their 3.6L hard. For example; accelerating up a hill at highway speeds.

My JLUR seems to hover at 31psi-32psi for most of my driving but it rises abruptly if I push the engine hard, and then rapidly decreases back to 32psi when I let off the gas. I am wondering how near to normal my engine is compared to the many others being driven.

What sorts of numbers do you see on the upper end of the range?

Thank you!

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[WranglerMan]

Normal….mine does the same but after a few stops and starts it settles in at 31 or so.

 

[Carolina Jeeper]

I see low 70's on semi hard accelerations at times. Oil pressure returns to the commonly seen 31 psi very quickly afterwards. Mine has Been that way since I've been monitoring oil pressure after break in. Currently at 28K miles and it'll still do this.

 

[blnewt]

I'm not sure exactly what rpm the oil pressure rises but seems to have 2 distinct pressures, around 30 for driving up to 3.5k rpm, and greater than 60 at rpms over that. It's not a slow linear rise to the high pressure level but a pretty abrupt jump to the high pressure.

 

[JEEPIDON]

The 3.6 has a two stage oil pump.

 

[Yellow Cake Kid]

I see low 70's on semi hard accelerations at times. Oil pressure returns to the commonly seen 31 psi very quickly afterwards...

Thanks for posting your observations.

I rarely have the oil pressure readout displayed, but yesterday I did, and on a hard pull up a highway hill I was surprised to see the rapid rise in pressure. I was pushing the gas while the engine surged towards a downshift and it spiked up to 88psi for a moment.

I did an oil change a few days ago and this was the first outing since, I had the oil display up so I could see if the system was stable, and was alarmed for a moment when I looked down and saw the high figure.

After our day trip I purposely tried a few accelerations on flat land and saw the psi reach 70+/- before dropping back to 31.

I had not paid much attention to this before, as I was primarily interested in maintaining a minimum pressure, and if that seemed stable I was satisfied.

Thank you.

 

[mwilk012]

Like many modern vehicles, the pentastar 3.6 has a 2 stage oil pump. The pump is metered by a duty cycle based solenoid stuck right inside the body of the pump, that activates stage 2 at 3,000 rpm. Normal stage 1 pressure is 30 psi. Normal stage 2 pressure is around 75 psi.

 

[Yellow Cake Kid]

Any thoughts about seeing 85+psi momentarily on one particular acceleration?

I had "exactly" 5 quarts of brand new 0W-20 Penzoil that had been driven approximately 10 miles when I saw this happen.

As I mentioned above, I was climbing a grade on a two lane highway, and had to accelerate a little harder than I would normally drive, while trying to avoid having a stream of tailgate drivers run me over.

 

[mwilk012]

Any thoughts about seeing 85+psi momentarily on one particular acceleration?

I had "exactly" 5 quarts of brand new 0W-20 Penzoil that had been driven approximately 10 miles when I saw this happen.

As I mentioned above, I was climbing a grade on a two lane highway, and had to accelerate a little harder than I would normally drive, while trying to avoid having a stream of tailgate drivers run me over.

normal. Listed pressures are for steady state conditions.

 

[Yellow Cake Kid]

Thanks for the info.

These digital pressure readouts scroll through numbers so rapidly, it can be disconcerting if you are unfamiliar with the movements.

Thank you.

 

[mwilk012]

Thanks for the info.

These digital pressure readouts scroll through numbers so rapidly, it can be disconcerting if you are unfamiliar with the movements.

Thank you.

Go out on the highway in manual shift mode and rev up above 3k and let it hang there for a while. You'll get a better understanding of how it works.

 

[MTGOAT]

I have a situation where my oil PSI gets hung at 80psi and stays there. The result is a very slow running engine. Basically feels like it goes into limp mode. No matter how high you run the RPMs (6 speed manual) it will not go anywhere. I need to shut the entire engine off and start it back up for it to clear. been doing this to me for about 6 months. (15k miles on it). Had it to the service department a few weeks ago. They flashed the PCM, didn't fix it. then they replaced the oil pressure switch which I had already done. Didn't fix it.

This is in junction with the jeep not wanting to start even with good batteries. Service department blamed the starting issue on the oil pressure switch even though there is a TSB out for the ESS.

Needless to say, I will be taking the jeep back next week for it's second look at the stuck oil pressure.

 

[mwilk012]

I have a situation where my oil PSI gets hung at 80psi and stays there. The result is a very slow running engine. Basically feels like it goes into limp mode. No matter how high you run the RPMs (6 speed manual) it will not go anywhere. I need to shut the entire engine off and start it back up for it to clear. been doing this to me for about 6 months. (15k miles on it). Had it to the service department a few weeks ago. They flashed the PCM, didn't fix it. then they replaced the oil pressure switch which I had already done. Didn't fix it.

This is in junction with the jeep not wanting to start even with good batteries. Service department blamed the starting issue on the oil pressure switch even though there is a TSB out for the ESS.

Needless to say, I will be taking the jeep back next week for it's second look at the stuck oil pressure.

sounds like one of two problems, PCM or oil pump stuck.

 

[roaniecowpony]

This is from the service manual. As you can read at the bottom, it defaults to a high volume/pressure if the PCM fails to get a low pressure signal to the pump solenoid or the solenoid fails. There is another failure mode, the pump can mechanically "stick" in the high volume/pressure configuration.

I would ask if they can readout or monitor the PCM signal. If it's working as it should, the wire harness or the pump assy are the next candidates.

 

[mwilk012]

This is from the service manual.

Very good, simple explanation here. I was digging through my archives but looks like I deleted the picture I had of a 3.6 oil pump we had replaced. It's a pretty good design.

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