Oil Pressure fluctuating and power dropping

Allen Brandes · Jun 2, 2020

2001 7.3L Superduty. 238K miles. Idles well. On the road, oil pressure starts fluctuating, slowly, and engine loses power as oil pressure drops. As pressure comes back up, engine takes off again. Oil level about 3/4 full. Recent oil change.
What's going on??

DaveBen · Jun 2, 2020

Why not fill it up to FULL on the dip stick. This may be your problem.

Allen Brandes · Jun 2, 2020

DaveBen said:
Why not fill it up to FULL on the dip stick. This may be your problem.

Will try that. Didn't think level should make that much difference

snicklas · Jun 2, 2020

The 7.3 and 6.0 PSD HEUI Injectors (Hydraulically-operated, Electronically-actuated Unit Injector) uses a pump (HPOP - High Pressure Oil Pump) it use engine oil that is pressurized into the 1000’s of PSI, to fire the injectors, On a 7.3 and 6.0 the engin oil level can get low enough the engine won’t run. Not completely out of oil, just really low. This is why a good quality oil, and changed regularally is important in the HEUI PSD’s....

DaveBen · Jun 2, 2020

The people who changed your oil were going cheap by saving themselves a gallon of oil. That is enough to do a small car's oil change.

Threesuns1 · Jun 11, 2020

I was told several years ago to use only the Motorcraft oil filter by a mechanic that worked on 7.3's in International school buses. As I recall, he explained it had something to do with oil pressure and HPOP to the injectors. Has anyone else heard of this?

snicklas · Jun 12, 2020

Yes, use only Mortorcraft/Racor/IH oil and fuel filters on the PSD’s, especially the 6.0. I know the 6.0 filters were patented, so the aftermarket either had to pay to make the correct, or they made one that is 99% correct. In the 6.0 that 1% is what gets you.... For me, the extra couple bucks for a Motorcraft filter (or I have found going to the local IH Truck dealer I can get them a bit cheaper) is worth not causing issues.

7MAGMIKE · Jul 9, 2020

I have never used anything but Amsoil, Wix, or Donaldson oil filters. Never any ill side effects and my 7.3 has 375,000 + miles on it. Be sure to top it off with a good quality oil (I use only Amsoil synthetic). I would never go to an oil change shop. Do you really know what they are servicing it with NO, that's why I do my own oil changes.

Oil Pressure fluctuating and power dropping

Allen Brandes

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