Engine Compression Inspection

NOTE: After the inspection, you must reset the powertrain control module (PCM). Otherwise, the PCM will continue to stop the fuel injectors from functioning.

Warm up the engine to normal operating temperature (cooling fan comes on).
Turn the ignition switch OFF.
Connect the Honda Diagnostic System (HDS) to the data link connector (DLC) (see step 2 GENERAL TROUBLESHOOTING INFORMATION ).
Turn the ignition switch ON (II).
Make sure the HDS communicates with the vehicle and the PCM. If it doesn't communicate, troubleshoot the DLC circuit (see DLC CIRCUIT TROUBLESHOOTING ).
Select PGM-FI, INSPECTION, then ALL INJECTORS OFF function on the HDS.
Turn the ignition switch OFF.
Remove the six ignition coils (see IGNITION COIL REMOVAL/INSTALLATION ).
Remove the six spark plugs.
Attach the compression gauge to a spark plug hole.

Fig 1: Identifying Compression Gauge To Spark Plug Hole
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Open the throttle fully, crank the engine with the starter motor and measure the compression.
Compression Pressure: Above 930 kPa (9.5 kgf/cm ² , 135 psi)
Measure the compression on the remaining cylinders.
Maximum Variation: Within 200 kPa (2.0 kgf/cm ² , 28 psi)
If the compression is not within specifications, check the following items, then remeasure the compression.
- Damaged or worn valves and seats
- Damaged cylinder head gasket
- Damaged or worn piston rings
- Damaged or worn piston and cylinder bore
Select PCM reset (see PCM RESET ) to cancel the ALL INJECTORS OFF function on the HDS.