How to Turn Up the Fuel on a 7.3 Injector Pump

by Francis Walsh

Ford truck owners who like the durability of the factory fuel settings on their 7.3L diesel engine have no need to turn up the fuel on a 7.3 injector pump. On the other hand, a large portion of the market likes to increase performance. Turning up the fuel adds 25 horsepower without any cost at all. What you might not know about this engine is that you can add more power without adding any more equipment.

Step 1

Disconnect the battery from the engine. Loosen each cable clamp with a wrench and secure the loose ends away from the battery.

Step 2

Locate the injection pump at the front of the engine. On the passenger side of the injection pump there is a little cover that protects the adjustment screw. It is shaped like home plate on a baseball field. Find this cover. Loosen the two bolts and remove the cover after placing rags and a catch can under the engine to collect the half-pint of fuel contained in the adjustment port.

Step 3

Align the engine so the adjustment screw can be accessed. By turning the engine over by hand you can acquire the right alignment. You will not see the adjustment screw until the engine is in the right position. Use a ratchet and socket on the end of the fan shaft to turn the engine by hand.

Step 4

Insert an Allen head wrench into the top of the adjustment screw and turn the screw one quarter turn clockwise. Push on the end of the wrench firmly as the screw will hardly feel like it is moving. Check how much it has moved to be sure that you have not moved the setting too radically. This adjustment should only be done for one-quarter of a turn on the adjustment screw and no more.

Replace the cover to the injector pump and tighten the two bolts with a wrench. Get into the truck and turn the key on to activate the injector pump to fill the pump before starting. Wait 30 seconds and start the engine.


  • Use a mirror to see around obstructions. Have a friend turn the engine while you look into the adjustment port to watch the opening expose the adjustment screw while the engine is turned over by hand. Install a pyrometer after turning up the fuel pressure on a 7.3 L diesel engine to monitor EGT (exhaust gas temperature).


  • Exhaust Gas Temperatures (EGT) can rise dramatically after the fuel pressure has been increased. Without proper monitors, the engine can damage internal parts from the excess heat. Diesel fuel will ignite upon coming in contact with flame or hot surfaces. Don not attempt to turn up the fuel on a 7.3 injector pump while the engine is hot or around open flame.

Items you will need

  • 7.3L Ford diesel engine
  • Wrenches
  • Ratchet (1/2-inch drive)
  • Sockets
  • Allen wrenches
  • Catch can
  • Rags

More Articles