Zontes ZT350T-D, Maintenance Manual

Page: 48 / 152

48 / 152
f. Pull out the high-pressure oil pipe from the bracket at
the cylinder head.
g. Pull out the high-pressure oil pipe in the direction of the
arrow after pressing down the anti-dropping lock.
h. After replacing the new high-pressure oil pipe, refer to
the disassembly steps to restore it.
3. Fuel pump
3.1 Use oil pressure gauge to measure fuel
pressure
a. Refer to steps a to c of "Remove stepper motor and
clean up carbon deposits" in the throttle valve body, first
remove the seat cushion and storage box components, and
remove them as shown in the figure below.
b. Unplug the fuel pump and start the engine to idle until
the engine stops. Turn the engine stop switch to " ",
power off the vehicle and lock the vehicle. After putting on
waterproof and oil-proof gloves, press the anti-trip lock and
pull out the high-pressure oil pipe in the direction of the
arrow.
c. Connect the high-pressure oil pipe of the original car to
the pressure gauge, and find another high-pressure oil pipe
to connect the pressure gauge and the fuel injector.
Start the vehicle, let the engine run at idle speed, and
measure the fuel pressure. D350 the standard pressure is:
350±10kPa (3.75±0.1Kgf/cm2, 50.8±1.45 psi). Check valve
performance: hold the pressure for 1 minute, the pressure
should be ≥300kPa (3.06Kgf/cm2, 43.5 psi).
3.2 Simple test of fuel pump
If you do not have the special equipment conditions, you
can do a simple test.
After the vehicle is in the stalled state, unlock the vehicle
and turn on the stall switch. If you do not start the engine,
you should be able to hear the sound of the fuel pump; or
pinch the high-pressure fuel pipe from the bottom with your
hands, and you should feel obvious pressure. Take care to
avoid the muffler to prevent burns. If it is in the engine
starting state, the whole vehicle shall be powered off for
more than 10 seconds and then check according to the above
operation.
4. Treatment of abnormal fuel pressure
If the fuel pressure is higher than the standard value,
replace the fuel pump. If it is lower than the standard value,
you need to inspect the following items:
a. Whether the fuel pipe is leaking;
b. Whether the fuel tank vent pipe is blocked or bent
excessively;
c. Whether the fuel pump filter is blocked;
d. Whether the fuel pump is faulty;
e. Whether the fuel is insufficient.