Engine oil pressure issue

[Papawolflopez]

Engine oil pressure gauge fluctuates along with lower rpm and a muffled backfire on passenger side between the speeds of 40-70 I have replaced the oil pressure switch the oil pump along with the oil pick up tube. Rearmain seal. Spark plugs

What could be the issue?

 

[Papawolflopez]

I took a video of what it does, but I don’t know how to add it

 

[Fless]

Host your video somewhere (like YouTube, etc.) and post a link to it here.

 

[Papawolflopez]

Engine oil pressure gauge fluctuates along with lower rpm and a muffled backfire on passenger side between the speeds of 40-70 I have replaced the oil pressure switch the oil pump along with the oil pick up tube. Rearmain seal. Spark plugs

What could be the issue?

I took a video of what it does, but I don’t know how to add it

 

[swathdiver]

Well, I set my alarm for 6:15 AM to watch it tomorrow... LOL

 

[swathdiver]

While we're waiting, tell us how many miles are on the engine and which engine is it? Aluminum or Iron 5.3 or 6.2 or 4.8?

 

[rdezs]

Backfire.... Have we scanned for any codes? Otherwise there's a huge list of possibilities. The list gets larger if this is an AFM/DOD engine, and if VVT is in play.

After scanning for codes I think I would do a compression and leak down test to get a complete picture. If it passes that, and if there's no codes being thrown, we will need live data when it's happening.

 

[OR VietVet]

Engine oil pressure gauge fluctuates along with lower rpm and a muffled backfire on passenger side between the speeds of 40-70 I have replaced the oil pressure switch the oil pump along with the oil pick up tube. Rearmain seal. Spark plugs

What could be the issue?

While you had the old switch out, why not attach a mechanical gauge with a long enough hose that allows you to come out the back of hood and tape gauge to w/s and see it? I understand the backfire but am confused about, "with lower rpm". "Between the speeds of 40-70 mph" means the backfire and lower oil pressure is when you drop to 40 mph or the engine speed will drop to 40 mph, all by itself? Very confusing description.

By the way, welcome to the forum from Oregon.

 

[Papawolflopez]

Well, I set my alarm for 6:15 AM to watch it tomorrow... LOL

Sorry about the video. It won’t let me add today.

 

[Papawolflopez]

It is a 2007 5.3 4 x 4 LTZ also the guy I bought it from lied about mileage reads now at 127000 but really it’s 200+
Just put in newly rebuilt 4l60E
And I’m not sure of type of engine so I posted my vin

 

[Fless]

Vin 8th digit=0 LMG 5.3L iron block Flex Fuel if it hasn't been changed.

 

[steiny93]

Which oil pump did you install? What was the oil pressure before the pump swap?

Low oil pressure will be caused by either lack of volume coming out of the pump or the engines tolerances (bearing clearance's, check valves open, lifters, etc) unable to maintain the desired pressure.

If we assume the pump is good then it'll be:
- check valve in the pan (unlikely)
- wrong oil filter (guessing not this)
- bearing clearances to big (cam bearings are also known to move over and cause this)
- lifters letting oil by (pins jamming)

those would be where I'd start to look

 

[2006Tahoe2WD]

IMHO - the oil pressure seems low. However, you list new pickup tube (I assume new O-ring as well), oil pump, oil pressure sender? With all that replaced I don't see why you would have low oil pressure unless oil is leaking past various bearings/etc.

 

[Papawolflopez]

Vin 8th digit=0 LMG 5.3L iron block Flex Fuel if it hasn't been changed.

Would clogged cats cause this