Lancer L4-2.4L (4B12) (2009)
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Compression Check: Testing and Inspection
COMPRESSION PRESSURE CHECK
Required Special Tool:
MB991958: Scan Tool (M.U.T.-III Sub Assembly)
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MB991824: V.C.I.
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MB991827: M.U.T.-III USB Cable
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MB991910: M.U.T.-III Main Harness A
1. Before inspection, check that the engine oil, starter and battery are normal. Also, set the vehicle in the following condition:
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Engine coolant temperature: 80 - 95° C (176 - 203° F)
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Lights and all accessories: OFF
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Transaxle: Neutral (P range on vehicles with CVT)
NOTE: On vehicles for Canada, the headlight, taillight, etc. remain lit even when the lighting switch is in "OFF" position but this is no problem
for checks.
2. Turn the ignition switch to the "LOCK" (OFF) position.
3. Disconnect the connector of the ignition coil, and then remove all the ignition coils and the spark plugs.
4. Disconnect the all of the injector connectors.
WARNING
Keep your distance from the spark plug hole when cranking. Oil, fuel, etc., may spray out from the spark plug hole and may cause serious
injury.
5. Cover the spark plug hole with a shop towel etc., after the engine has been cranked, check that no foreign material is adhering to the shop towel.
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 200 r/min): 1,440 kPa (209 psi)
Limit (at engine speed of 200 r/min): Minimum 1,000 kPa (145 psi)
8. Measure the compression pressure for all the cylinders, and check that the pressure differences of the cylinders are below the limit.
Limit: Maximum 98 kPa (14 psi)
9. If there is a cylinder with compression or a compression difference that is outside the limit, pour a small amount of engine oil through the spark
plug hole, and repeat the operations in steps from 6 to 8.
1) If the compression increases after oil is added, the cause of the malfunction is a worn or damaged piston ring and/or cylinder inner surface.
