How to Replacing the Injection Pump in 2000 F-350 7.3L Ford

High Pressure Oil Pump

This post will walk you through the replacement process.

Apparently there is no injection pump its actually a high pressure oil pump which powers the injectors.


The symptoms which lead me to believe I needed to replace the pump:

  • At a certain RPM (about 2500) the truck lost power as if it ran out of fuel.
  • Going on the freeway or up a steep hill became impossible.
  • Over a few months this threshold came down to about 1800 RPM at times, which meant going over 35mph became difficult.
  • Upon hitting the RPM threshold, power loss occured and the truck could not rev beyond 1500 RPM.
  • After pulling over or coasting for 30 seconds, I could then rev back to the original threshold before the cycle repeated.
  • Adding a pressure checker between the fuel filter and high pressure pump, revealed no abnormalities.
  • A pressure checker after the high pressure pump revealed loss of pressure at the RPM threshold.


On the 2000 7.3L, the fuel filter sits atop the engine. The high presure oil pump is directly beneath the fuel filter and back about 6″ towards the firewall. The fuel filter assembly must be completely removed to reveal the high pressure oil pump.

What you need

  • High temp gasket maker
  • Locktite blue
  • Extra quart of oil
  • Rebuilt high pressure oil pump

Remove the oil pump

  1. Put a large pan or cardboard beneath vehicle, you will drop about a quart of fluid (oil, diesel and coolant).
  2. Drain fuel filter then completely remove fuel filter housing and assembly (everything attached to fuel filter, you will spill some oil here).
  3. This will reveal a gear which powers the oil pump.Filter housing removed
  4. Look at the gear, there is an 18mm bolt in the middle attaching the gear to the oil pump. Directly in front of that bolt is a removable cover attached to the assembly around the gear. Remove the cover (8mm bolts). To get to the cover, unhook the the coolant line and electrical sensor bracket in front of the cover. Unhook any wires attached to the cover.
  5. The 18mm bolt is now exposed. Wedge a screw driver into a tooth of the gear to keep the engine from spinning and loosen the 18mm bolt.  Use a breaker bar or a pipe around your wrench to get leverage.  Don’t worry you wont break the tooth off. Loosen but leave the bolt in.
  6. Unhook high pressure oil ines and any wiring attached to the oil pump
  7. Take out the 2 bolts holding oil pump to the housing
  8. Wipe down the gear and housing around the gear. To be safe, use a sharpie marker and draw a line across the housing and to gear tooth to keep the gear in the same position.
  9. Take out the 18mm bolt and remove the oil pump being careful to leave the gear in the exact same place.

Replacing the oil pump

  1. There is some type of sensor on the old oil pump which must be removed and placed on the new one.
  2. Use a large wad of paper towels and soak up any oil that dropped out and pooled up on the top of the engine. Reach way back all along the top of the engine to soak it all up to keep your truck from smelling like burnt oil for the next 3 weeks.
  3. Put a line of  locktite on the 18mm bolt.
  4. Keeping the gasket aligned on the new oil pump, carefully place it back into position while sliding the 18mm bolt through the gear and lightly threading it into the oil pump. (To be safe, make sure the gear is aligned still).
  5. Thread in the 2 bolts holding the oil pump to the housing. Tighten all bolts nice and tight. For the 18mm bolt use the breaker bar and wedge a screwdriver into a gear tooth, and tighten it really good.
  6. Hookup all wires and oil hoses to the oil pump.
  7. Replace the cover in front of the 18mm bolt (use gasket maker if needed). Replace connections and sensors on the cover.
  8. Hookup coolant line.
  9. Clean rubber gasket around the gear, coat in oil and replace the filter housing unit.
  10. Hookup all oil, fuel and electrical lines to the filter and housing unit, and bolt it down.


Refill the the fuel filter by turn on and off the ignition ofr 5 seconds. Do this a dozen times. Then have a friend open up the fuel filter release valve while your turn on the ignition to force out any air. Do this until diesel sprays out. Say a short prayer, then start it up. Idle for 20 seconds, then shut off and check oil level. You’ll probably need to add a half a quart or more. Run again for a minute to be satisfied everything works… then let the truck sit for half a day or so to let the gasket maker dry.


In my opionion the exact replacement and alignment of the gear which drives the pump is not necessary, but I did it just in case.

Total work time: 3hrs.


Did veggie oil have anything to do with the pump going bad? At no point does fuel actually come in contact with this pump, so I’ll need to research this.

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