Engine Compression

Disconnect fuel shut-off solenoid wire. Remove injectors. Install Compression Gauge and Adapter (J-35129) into injector hole. Install injector retaining clamps. Crank engine until no further rise in pressure is indicated on gauge.

If piston rings and valves are in good condition, the highest pressure increase will be seen on first compression stroke. Compression will build up to maximum on subsequent strokes.

If compression increases only gradually on each compression stroke, this indicates that valve seats may be burnt or worn valve guides. If maximum pressure is low on all cylinders, this indicates worn pistons, rings or valves.