Compression Pressure Check - Mitsubishi MOTORS Space Runner 1999 Workshop Manual Supplement

11B-12
Compression gauge
ENGINE <4G1> – ENGINE <4G1> –
7. If there is a deviation from the standard value, check the
following items:
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 distributor 7-pin 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,
6. Set compression gauge to one of the spark plug holes.
7. Crank the engine with the throttle valve fully open and
measure the compression pressure.
Standard value (at engine speed of 250 – 400 r/min):
Limit (at engine speed of 250 – 400 r/min):
On-vehicle Service On-vehicle Service
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.
1,598 kPa
min. 1,161 kPa
11100260642