Compression Test

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

NOTE: Removing fuses and disconnecting electrical components causes the powertrain control module (PCM) to come up with an error message. After measurement has been carried out this error message should be cleared from memory by connecting NGS.

NOTE: Only check the compression pressure with the valves set to the prescribed clearance (if this can be adjusted).

The compression pressure should be checked with the engine at operating temperature.
Differing designs of compressor pressure recorder and varying starter motor speeds usually only make it possible to check that the compression is the same in all cylinders.





1. Remove the fuel pump relay.
Remove the cover from the central junction box.
Fuel pump relay (relay R9).

WARNING: On manual transmissions put the transmission into neutral. On automatic transmissions select "P".

Start the engine: the engine will start up, run for a few seconds and then stall.

2. Remove the cover plate from the cylinder head cover.
3. Remove the spark plugs.
Pull off the spark plug connectors.
Pull off the ignition coil connector.

WARNING: On manual transmissions put the transmission into neutral. On automatic transmissions select "P".

NOTE: Operate the starter motor with wide open throttle until the pointer on the measuring device stops rising.

4. Carry out the measurement in accordance with the instructions supplied with the measuring device on every cylinder using the compression pressure recorder.
5. Refit the components in the reverse order, observing the specified tightening torques.
6. Reset the PCM fault memory.
Check The Compression Pressure 2.5L





1. Open the central junction box and remove the fuel pump relay.

WARNING: On manual transmissions put the transmission into neutral. On automatic transmissions select "P".





2. Start the engine. The engine will start up, run for a few seconds and then stall.





3. Remove the engine cover.





4. Pull off the spark plug wires and remove the spark
DIMS.
5. Disconnect the connector from the coil.

WARNING: On manual transmissions put the transmission into neutral. On automatic transmissions select "A'.

NOTE: Operate the starter motor with wide open throttle until the pointer on the measuring device stops rising.

6. Using the compression pressure recorder carry out the measurement on every cylinder.
7. Install the components in the reverse order, observing the specified tightening torques.
8. Reset the PCM fault memory.