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Home >> Ford >> 1994 >> F 250 2WD Pickup V8-7.3L DSL >> Repair and Diagnosis >> Powertrain Management >> Tune-up and Engine Performance Checks >> Compression Check >> Testing and Inspection
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Compression Check: Testing and Inspection



AllData Editors Note - Ford does not provide a cranking pressure specification, only an acceptable range.

Compression Test Procedures

WARNING: Red-striped wires carry 115V DC. Severe electrical shock may be received. Do not pierce.

CAUTION: Do not pierce engine electrical wires or damage to the harness may occur.

1. Make sure battery is fully charged. Operate the engine until normal operating temperature is reached. Turn the ignition switch to OFF. Remove the right and left rocker arm cover as outlined in this section. Disconnect the Injection Driver Module (IDM) relay or the camshaft position sensor to prevent accidental engine starting. Remove all glow plugs.






2. Install Rotunda Compression Tester 014-00701 or equivalent and adapter 014-00931-1 in No.1 cylinder glow plug hole.

3. Install an auxiliary starter switch in starting circuit. With the ignition switch OFF, crank the engine 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.

Test Conclusion

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:




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