F 250 2WD Pickup V8-7.3L DSL (1990)
Compression Check: Testing and Inspection
Compression Test Procedures
The following procedures is to be used when checking compression:
1. Make sure battery is fully charged. Operate the engine until normal operating temperature is reached. Turn the ignition switch to off. remove air
cleaner and / or intake opening cover. Disconnect injection pump solenoid leads from injection pump to prevent accidental engine starting.
Remove all glow plugs.
2. Install Rotunda Compression Tester 014-00701 or equivalent in number 1 cylinder glow plug hole.
3. Crank the engine (with the ignition switch off) at least five pumping strokes. Record highest reading indicated. Note the approximate number of
compression strokes required to obtain the highest reading.
4. Repeat the check on each cylinder, cranking the engine approximately the same number of compression strokes.
Compression pressures are considered normal if the lowest reading cylinder is within 75 percent of the highest. Variations exceeding 75 percent indicate
an improperly seated valve or worn or broken piston rings.
Caution: Do not add oil to cylinder. This could cause hydrostatic lock.
Compression Test Pressures