Compression Pressure Check - Mitsubishi Pajero Pinin 1999 Workshop Manual

ENGINE <4G9-GDI> ±
Crank angle sensor
connector
On-vehicle Service
6. Check the CO contents and the HC contents at idle.
NOTE
This measurement should be performed in less than
approximately 4 minutes since the engine speed become
the idle speed.
Standard value
CO contents: 0.6% or less
HC contents: 200 ppm or less
7. If there is a deviation from the standard value, check the
following items:
Diagnosis output
Fuel pressure
Injector
Ignition coil, spark plug
EGR control system
Evaporative emission control system
Compression pressure
NOTE
Replace the three way catalyst when the CO and HC
contents are not within the standard value, even though
the result of the inspection is normal on all items.

COMPRESSION PRESSURE CHECK

1. Before inspection, check that the engine oil, starter and
battery are normal. In addition, set the vehicle to the
pre-inspection condition.
2. Remove all of the ignition coils and spark plugs.
3. Disconnect the crank angle sensor connector.
NOTE
Doing this will prevent the engine-ECU from carrying out
ignition and fuel injection.
4. Cover the spark plug hole with a shop towel etc., and
after the engine has been cranked, check that no foreign
material is adhering to the shop towel.
Caution
(1) Keep away from the spark plug hole when
cranking.
(2) If compression is measured with water, oil, fuel,
etc., that has come from cracks inside the cylinder,
these materials will become heated and will gush
out from the spark plug hole, which is dangerous.
5. Set compression gauge to one of the spark plug holes.
6. Crank the engine with the throttle valve fully open and
measure the compression pressure.
Standard value (at engine speed of 300 r/min):
1,720 kPa
Limit (at engine speed of 300 r/min):
Min. 1,337 kPa
11A-11