Ford came out with the 7.3 liter Power Stroke diesel engine in about 2002 to be included in their line of industrial, marine and on-highway engines. For the highway it can be found in the F-Series Super Duty trucks and other models. Like all engines, if the power seems to be getting weaker, a compression check will tell you if you should think about an overhaul.
Remove all the glow plugs from all the cylinders with the glow plug wrench. Be careful not to allow dirt into the glow plug holes.
Screw the glow plug adapter into one of the cylinders, and screw the compression gauge into the glow plug adapter.
Crank the engine and let it turn over five times. Note the reading on the compression gauge. It should be at least 350 psi (pounds per square inch). Record the reading on your note pad.
Remove the compression gauge and the glow plug adapter and repeat the compression reading for all of the cylinders. Record all of the readings on your note pad. The lowest reading should be no lower than 25 percent less than the highest reading.
