Mitsubishi 6M60-TL, Service Manual

Page: 46 / 330

11-10
1. Measuring Compression Pressure
Service standards
Special tools (Unit: mm)
• A drop in compression pressure can be used as a guide to determine when the engine should be overhauled.
• Measure the compression pressure at regular intervals. Keeping track of its transitions can provide a useful tool
for troubleshooting. On new vehicles and vehicles with newly replaced parts, the compression pressure will be
somewhat higher depending on the break-in condition of piston rings, valve seats, etc., but this will return to nor-
mal as the parts wear down.
• Before inspection, confirm that the engine oil, starter, and battery are in normal condition, and satisfy the following
conditions.
• Warm up the engine until the coolant temperature reaches approximately 75 to 85
°
C.
• Turn off the lights and auxiliaries.
• Place the lever in neutral.
• Remove the fuse for fuel cut to prevent fuel from being injected
while the engine is cranked using the starter.
CAUTION
• When cranking the engine, never shut off the power sup-
plied to the engine electronic control unit by disconnecting
the engine electronic control unit connector or other similar
methods. If the engine is cranked with the power to the en-
gine electronic control unit shut off, the supply pump will
not be controlled by the electronic control unit, causing the
supply pump to be malfunctioned.
Location Maintenance item Standard value Limit Remedy
– Compression pressure
Each cylinder (at 200 rpm)
2,940 kPa
{30 kgf/cm
2
}
1,960 kPa
{20 kgf/cm
2
}
Inspect
Cylinder-to-cylinder pres-
sure difference
–
390 kPa
{4 kgf/cm
2
}
or less
Inspect
Mark Tool name and shape Part No. Application
MH063384 Measuring compression pressure
Compression gauge
adapter
A
M16
×
18
GENERAL INSPECTION AND ADJUSTMENT