Komatsu PC88MR-10 Shop Manual page 368

30 Testing and adjusting
Engine and cooling system
Testing
(PC88MR-AE20-363-K-00-A)
1. Preparation
1) Remove the air compressor.
2) Remove injector return tube (3) and pressure
limiter return tube (4) connected to joint bolt
(2) of return block (1).
3) Insert spacers H1 (2 pieces) into the return
block side, and tighten the removed joint bolt
again.
a Be sure to install seal washers H3 (3
pieces) to each end of spacers H1.
4) Remove the joint bolt on the cylinder head
side of injector return tube (3), set joint H2,
and tighten the joint bolt again.
5) Connect test hose H4 to the end of joint H2.
6) Set joint H2 to pressure limiter (5), and
tighten the removed joint bolt again.
7) Connect test hose H4 to the end of joint H2.
30-18
8) Return the air compressor.
Preparation is completed.
2. Testing leakage from pressure limiter
1) Arrange the route of test hose H4 so that it
does not sag, and put its end in a oil pan
(container to catch the fuel).
2) Start the engine, and run it at 1,600 rpm with
no load.
3) After the engine speed is stabilized, measure
the leakage for 1 minute by using measuring
cylinder H6.
a Measuring duration can be 20 seconds if
the leaked amount is multiplied by 3 after
the measurement.
a For standard values, see "Standard value
table for engine".
4) Stop the engine after the measurement is
over.
3. Testing fuel return rate from injector
a While you are measuring the fuel return rate
from the injector, keep the hose on the
pressure limiter side connected and its end in
the oil pan (container to catch the fuel).
1) Start the engine, and run it at the rated
horsepower.
2) After the engine speed is stabilized, measure
the return rate for 1 minute by using
measuring cylinder H6.
a You may measure the return rate for 20
seconds and multiply it by 3 to judge.
a If the error of no-pressure feed occurs on
the supply pump, the engine speed may
not rise. In this case, record the engine
speed during the test as well.
a For standard values, see "Standard value
table for engine".
PC88MR-10