Help Needed 99 7.3L Oil Pressure Problem.

[BJS]

We are all guessing at this point. These trucks are meant to be scanned.

Dave I'll respectfully disagree here, aside from ICP, IPR and the oil pressure sending unit readings there is little information to be gleaned from scanning. The important one of that trio is the sending unit reading and he's duplicated that with a mechanical gauge that is arguably more accurate. Given your knowledge I ask what potential codes or other abnormal sensor readings would you be expecting

Back to the original question at hand:

As has been mentioned you can have oil flow at zero psi meaning that the oil pump is working and moving oil however the restricted orifices that maintain the oil pressure are the likely problems at this point.

Quick and rather messy(I do mean really messy) test to show flowing oil is to remove the plug on the top of the hpop and see what comes out and how fast.

the oil flow is diagrammed on page 39 of the pdf for the 94-98 engines here

and while not shown well there are ports that squirt oil on the skirt of the piston to help ensure that the piston is kept cool

 

[DaveBen]

You are entitled to your opinion and it is certainly welcome. I am not going to argue the virtues of scanning vs not scanning, it is your truck. What should be said about scanning is this will show what the computer THINKS is the problem.

Dave

 

[KTMMDG]

Thanks everybody. I'll be trying everything in the next few days.
here's a Picture of her.

 

[KTMMDG]

Alright so, I checked the pickup tube just in case and it seems to be working properly. I haven't pulled the Valve covers yet but will probably be doing so soon. Turns out My dad has a scanner, we are looking for it when we find it we'll scan and see what turns up.

I put a mechanical gauge on where the filter housing unit is.
Here's the difference between checking it there and the reservoir.
Reservoir, Hot idle = 0psi. 2,000rpm = 25psi.
Filter housing unit, Hot idle = 0psi. 2,000rpm = 45psi.

I'm confused?

 

[CSIPSD]

Couple things...

The PCM has no way of knowing what the Low pressure oil pressure is, the sender in the HPO res is a on off switch. If you have less then 5psi the light on the dash comes on and the "gauge" on the dash reads zero. You can remove that sensor all together and nothing will happen other then the factory idiot light in the dash will stop working.

But if the truck has 0 low pressure oil the high pressure oil reservoir would be run dry very quickly, seconds...

What type of pressure gauge are you using? Mechanical? Electrical?

YouTube - Oil pressure, cold motor, tooling around the parking lot.

 

[KTMMDG]

Couple things...

The PCM has no way of knowing what the Low pressure oil pressure is, the sender in the HPO res is a on off switch. If you have less then 5psi the light on the dash comes on and the "gauge" on the dash reads zero. You can remove that sensor all together and nothing will happen other then the factory idiot light in the dash will stop working.

But if the truck has 0 low pressure oil the high pressure oil reservoir would be run dry very quickly, seconds...

What type of pressure gauge are you using? Mechanical? Electrical?

YouTube - Oil pressure, cold motor, tooling around the parking lot.

It is a mechanical gauge. Do you think the oil short circuit device could be a issue? or maybe the oil galley plugs?

 

[CSIPSD]

It is a mechanical gauge. Do you think the oil short circuit device could be a issue? or maybe the oil galley plugs?

If you have any air in the line you will get weird readings, kink in the line same thing... I am always suspect of mechanical gauges.

There is a port on the oil cooler, move your pressure gauge there and see what happens.

Like I said, these trucks will NOT run with no oil pressure, the HPO system will drain the little res in no time.

 

[KTMMDG]

If you have any air in the line you will get weird readings, kink in the line same thing... I am always suspect of mechanical gauges.

There is a port on the oil cooler, move your pressure gauge there and see what happens.

Like I said, these trucks will NOT run with no oil pressure, the HPO system will drain the little res in no time.

Alright checked the gauge for any air, kinks it's all solid. checked pressure at oil cooler port same readings there. I believe it's at least getting 8psi at idle.

 

[KTMMDG]

I also removed the left side valve cover and checked everything in there believe it or not it all looks like it's brand new! I will be removing the right side valve cover later today. If all looks as good as the left side I guess i'll go down and check the galley plugs.

 

[Tbar]

Alright so, I checked the pickup tube just in case and it seems to be working properly.

I gotta ask how you did this. Did you pull the engine and pan to check the P/U tube for cracks???

After you run the truck and get it hot.....pull the dipstick. Does the oil look foamy?


Tbar