Compression Pressure Check - Mitsubishi 4G6 Manual

ENGINE <4G6> - ENGINE <4G6> -
5. Set the CO, HC tester.
6. Check the CO contents and the HC contents at idle.
Standard value
7. If there is a deviation from the standard value, check
the following items:
D
D
D
D
D
D
D
D
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. Disconnect the spark plug cables.
3. Remove all of the spark plugs.
4. Disconnect the crank angle sensor connector.
NOTE
Doing this will prevent the engine-ECU from carrying out
ignition and fuel injection.
5. 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
2. If compression is measured with water, oil, fuel,
On-vehicle Service On-vehicle Service
CO contents: 0.5% or less
HC contents: 100 ppm or less
Diagnosis output
Closed-loop control (When the closed-loop control
is normal, the output signal of the oxygen sensor
changes between 0 - 400 mV and 600 - 1,000 mV
at idle.)
Fuel pressure
Injector
Ignition coil, spark plug cable, spark plug
Leak in the EGR system and in the EGR valve
Evaporative emission control system
Compression pressure
cranking.
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.
11A-9
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