Strange oil pressure change

FlipZ71 · September 16, 2019

2015 , 5.3 6speed 83,000 miles ,headers , 4.56 gears , trans thermo delete , BBP tuned within first 8,000 miles or so.

Truck is daily driver , some towing. Oil changed every 5000 miles. Currently using Amsoil SS. All other fluids serviced as needed.

Has been a great truck!!

I have 2 strange events.

1. Ac condenser failed. When replaced and ac charged up , within 30 minutes the truck would not idle correctly. It oscillated from 500 rpm too 900 , back and forth.

Scan code showed lean bank 1 , po71

Pulled MaF , cleaned , idle relearn , problem cleared up. For about 2 weeks I noticed it would now start idling slightly higher than normal on random days. So decided to replace the sensor.

Today replaced it.(correct one verified )

Today also changed out coolant fluid. Doing so I also replaced the thermostat with a 192 degree.

First thing I notice today when driving is my oil pressure has changed significantly.

Idle is normal but slightest tough of pedal it jumps to 60 and stays there at any light throttle position.

Before the mods today my pressure when hot idles at 30 , Driving pressure 40 .

I dont see how changing the MAF and the thermostat would have any effect at all on the oil pressure ?

It's a 2 stage pump , mechanical, nothing electronic should have an effect on it.

Just coincidence?? Or am I missing something here ?

Appreciate any input ...

1SLOW1500 · September 16, 2019

Little hard to say. Most of what you did has nothing to do with O2 sensors or bank 1 (driver side) seeing lean. With a scanner we can quickly see it it is still lean and what the issue is. the idle is not normal however is in the stock levels for the truck. there is idle speeds for ac control.

I wonder first how your maf was dirty or damaged. then we always see if there is oil in the intake. Has truck seen dealer "clean out bulletin" If all that checks out then we correct the code as it sounds like you did with new maf. then pull out the sensor clean and try it or replace sensor. if there is a pin size hole in exhaust then it would read lean.

Oil pressure is good at the 40 and even the 30. 60 is also fine but shouldn't stay high unless under engine load.

I would and I pause every time I was this..... sea foam the whole truck and clean out intake. should drive like new. As I question if somehow oil buildup is to blame. All these is uber cheap and great for engine.

Last we would normally again plug in the scanner/logger and even unplug the o2 sensors to force the truck into close loop fuel. just to see if it can run right. But we are reading the scanner for issue.

Oh and a maf calibration just because it is to easy not to do but that isn't the issue.

diyer2 · September 16, 2019

Need a good scan tool and know how to read the info IMO.

FlipZ71 · September 16, 2019

6 minutes ago, 1SLOW1500 said:

Little hard to say. Most of what you did has nothing to do with O2 sensors or bank 1 (driver side) seeing lean. With a scanner we can quickly see it it is still lean and what the issue is. the idle is not normal however is in the stock levels for the truck. there is idle speeds for ac control.

I wonder first how your maf was dirty or damaged. then we always see if there is oil in the intake. Has truck seen dealer "clean out bulletin" If all that checks out then we correct the code as it sounds like you did with new maf. then pull out the sensor clean and try it or replace sensor. if there is a pin size hole in exhaust then it would read lean.

Oil pressure is good at the 40 and even the 30. 60 is also fine but shouldn't stay high unless under engine load.

I would and I pause every time I was this..... sea foam the whole truck and clean out intake. should drive like new. As I question if somehow oil buildup is to blame. All these is uber cheap and great for engine.

Last we would normally again plug in the scanner/logger and even unplug the o2 sensors to force the truck into close loop fuel. just to see if it can run right. But we are reading the scanner for issue.

Oh and a maf calibration just because it is to easy not to do but that isn't the issue.

1 slow , with the new maf the idle is good now , no more lean code... seems fine

I agree my oil pressures are normal at 30 idle and 40 running , been that way for a while.

It's that after changing the maf and coolant thermostat this morning now my driving oil pressure stays constant at 60.

Makes no sense......

1SLOW1500 · September 16, 2019

Ah ok well that is funny. most people complain about low pressure at idle. What is the oil weight? you said amsoil SS.

I agree with Diyer2 you need a good scan tool as the factory indicator is crap. I would want to know first if that senor is reading right. I have added oil gauges to monitor better and I did see 12psi at idle and over 60 at wot. My oil sees much abuse.

If say the 2 stage pump was going out you would see spikes in pressure and generally low pressure not extra pressure.

FlipZ71 · September 17, 2019

7 hours ago, 1SLOW1500 said:

Ah ok well that is funny. most people complain about low pressure at idle. What is the oil weight? you said amsoil SS.

I agree with Diyer2 you need a good scan tool as the factory indicator is crap. I would want to know first if that senor is reading right. I have added oil gauges to monitor better and I did see 12psi at idle and over 60 at wot. My oil sees much abuse.

If say the 2 stage pump was going out you would see spikes in pressure and generally low pressure not extra pressure.

I run 5W30 in the Texas heat.

Agreed , would expect lower pressures if pump was goin out.

Well , on commute home today my driving pressure was back down to it's normal range at 40.....

Hmph...

Dunno.... runs great ,

Either ..

A. something was trapped in an orifice creating higher pressure

B. PUMP is on the way out

C. Sending unit acting up....

1SLOW1500 · September 17, 2019

In that case It leads me to think build up of oil. I know amsoil is good. Top 10. But that weight. I know it is a huge option here. So I let that one go.
Or/and lazy senor and gauge. I swear everytime I see mine I say what lie is going to make me freak out the rest of the drive.

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HeySkippyDog · September 17, 2019

You didn't say what weight oil you're using. I'm suspecting 30. Too heavy. Use 20.

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1SLOW1500 · September 17, 2019

You didn't say what weight oil you're using. I'm suspecting 30. Too heavy. Use 20.

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He said 5w30

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HeySkippyDog · September 17, 2019

He said 5w30

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Precisely. It's too heavy. See what the readings are with 0w-20 or 5w-20.

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Grumpy Bear · September 17, 2019

10 hours ago, FlipZ71 said:

I run 5W30 in the Texas heat.

Agreed , would expect lower pressures if pump was goin out.

Well , on commute home today my driving pressure was back down to it's normal range at 40.....

Hmph...

Dunno.... runs great ,

Either ..

A. something was trapped in an orifice creating higher pressure

B. PUMP is on the way out

C. Sending unit acting up....

Your going to laugh at me and that's fine. Sometimes when the MAF is unplugged and plugged back in it confuses the ECM and activates the second pump stage for one key cycle. Who knows why. Scared me the fist time it happen to mine. Your motor is fine.

FlipZ71 · September 17, 2019

16 minutes ago, Grumpy Bear said:

Your going to laugh at me and that's fine. Sometimes when the MAF is unplugged and plugged back in it confuses the ECM and activates the second pump stage for one key cycle. Who knows why. Scared me the fist time it happen to mine. Your motor is fine.

Ahh... lol so it happened to you as well....

Yeah so far 4 key cycles and hasn't run high pressure again so yea I'm calmed down !!

Thanks for the info!