Mystique V6-153 2.5L DOHC VIN L SFI (1999)
Compression Check: Testing and Inspection
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 compression pressure recorders and varying starter motor speeds usually only make it possible to check that the compression is the
same in all cylinders.
Check the Compression Pressure
1. Open the battery junction box and remove the fuel pump relay.
WARNING: Manual transaxles put 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 plugs.
