Please perform the check taking into account the following.
1. Reduce the pressure in the engine fuel system.
2. Using diagnostic equipment, verify that the fuel pressure has dropped to zero and the fuel temperature has reached the outside temperature or below 30°C (whichever is higher).
WARNING: Do not perform any work on the fuel injection system without making sure that the fuel pressure has dropped to zero and the fuel temperature has reached the outside temperature or below 30°C (whichever is higher). Failure to do so may result in an accident.
3. Remove the mudguard and engine crankcase protection (see Checking compression in cylinders).
4. Remove the glow plug relay.
5. Remove the decorative engine cover (see Removing and installing the decorative engine cover).
NOTE: The engine cover is mounted on three ball joints. The ball joints are not vertical but are tilted back at an angle of approximately 20°.
6. Disconnect the fuel injector electrical connectors.
7. Remove the EGR heat exchanger.
8. Remove the EGR valve.
9. Remove the glow plug power wire.
10. Remove the glow plugs.
11. Install the compression tester into the glow plug hole.
12. Turn the engine crankshaft with the starter.
NOTE: Continue turning the crankshaft until the pressure reading on the compression gauge stops increasing.
13. Measure the compression in all cylinders, following the compression tester manufacturer's instructions. Low compression in individual cylinders may result from valves not seating tightly in their seats, damaged cylinder head gaskets, broken or burnt piston rings. Low compression in all cylinders indicates worn piston rings.
NOTE: The ECM will receive an error message when the fuel pump relay is removed or electrical components are disconnected. After checking the compression, clear this message from the RAM using diagnostic equipment.
14. Install the parts in the reverse order of removal.
This publication was borrowed from the website: FordBook