TESTING AND ADJUSTING MEASURING FUEL PRESSURE
RELEASING REMAINING PRESSURE IN FUEL SYSTEM
12-14
140-3 SERIES
RELEASING REMAINING
PRESSURE IN FUEL SYSTEM
★ When the engine is running, pressure is generat-
ed in both the low-pressure circuit and high-pres-
sure circuit of the fuel line.
Low-pressure circuit: Feed pump – fuel filter –
fuel supply pump
High-pressure circuit: Fuel supply pump – com-
mon rail – fuel injector
★ For both the low-pressure circuit and high-pres-
sure circuit, the pressure automatically goes
down to a safe level 30 seconds after the engine
is stopped.
★ The remaining pressure in the fuel system must
be completely released before carrying out in-
spection of the fuel system or removal or instal-
lation of the equipment. Always follow the
following precautions when carrying out the op-
eration.
When inspecting the fuel line or removing or in-
stalling equipment, wait for at least 30 seconds
after the engine is stopped to release the re-
maining pressure in the fuel system before start-
ing the operation. (There is still pressure
remaining in the circuit, so do not start opera-
tions immediately after the engine is stopped).
MEASURING FUEL PRES-
SURE
★ Measure the fuel pressure only for the low-pres-
sure circuit between the feed pump – fuel filter –
fuel supply pump.
The high-pressure circuit between the fuel sup-
ply pump – common rail – fuel injector is under
extremely high pressure, so it cannot be meas-
ured.
1.
Remove fuel pressure measurement plug (1).
2.
Fit nipple of pressure test kit
A
, then connect
to the pressure test kit.
3.
Start the engine and measure the fuel pressure
at high idling.
4.
After completing the measurement, remove the
measurement equipment and set to the original
condition.
★ For the standard values, see "TROUBLE-
SHOOTING OF ELECTRICAL SYSTEM (E
MODE)"
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