Mitsubishi Fuso CANTER FE85DE6SLGP, Shop Manual

Page: 52 / 336

11-14
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 the compression measurement, confirm that the engine oil, starter, and battery are in normal condition.
• Place the vehicle in the following conditions.
• Warm up the engine until the coolant temperature reaches approximately 80 to 90
°
C.
• Turn off the lights and auxiliaries.
• Place the transmission in neutral.
• Place the steering wheel in the straight-ahead position.
• Remove the fuse (M9) to prevent fuel from being injected when
the engine is cranked by the starter.
CAUTION
• When cranking the engine, never shut off the power to the
engine electronic control unit by disconnecting the engine
electronic control unit connector or the like.
• If the engine is cranked while shutting off the power to the
engine electronic control unit, the electronic control unit
cannot control the supply pump and this may cause failure
to the pump.
Location Maintenance item Standard value Limit Remedy
– Compression pressure
Each cylinder (at 250 rpm)
3100 kPa
{32 kgf/cm
2
}
2400 kPa
{24 kgf/cm
2
}
Inspect
Cylinder-to-cylinder pres-
sure difference
–
500 kPa
{5 kgf/cm
2
}
or less
Inspect
Mark Tool name and shape Part No. Application
Compression gauge adapter
MH063853 Measuring compression pressure
A B C
M14
×
1.5 58
φ
7.2
ON-VEHICLE INSPECTION AND ADJUSTMENT