FUEL LINES
DESCRIPTION
DESCRIPTION
NOTE: High pressure fuel lines must be replaced
once disassembled.
All fuel lines up to the high pressure pump are
considered low-pressure. This includes the fuel lines
from the fuel tank to the fuel/lift pump, and the fuel/
lift pump to the high pressure pump. The fuel return
lines and the fuel drain lines are also considered low-
pressure lines. High-pressure lines are used between
the high pressure pump and the fuel rail and then
from the rail to the fuel injectors (Refer to 14 - FUEL
SYSTEM/FUEL
DELIVERY/FUEL
LINES
-
DESCRIPTION).
DESCRIPTION - HIGH PRESSURE FUEL LINES
NOTE: High pressure fuel lines must be replaced
once disassembled.
(Refer to 14 - FUEL SYSTEM - WARNING). The
high-pressure fuel lines are used between the fuel
injection pump and the fuel rail, and between the
fuel rail and fuel injectors.
OPERATION - HIGH PRESSURE FUEL LINES
WARNING:: HIGH - PRESSURE LINES DELIVER DIE-
SEL FUEL UNDER EXTREME PRESSURE FROM
THE INJECTION PUMP TO THE FUEL INJECTORS.
THIS MAY BE AS HIGH AS 1600BAR (23,200 PSI.).
USE EXTREME CAUTION WHEN INSPECTING FOR
HIGH - PRESSURE FUEL LEAKS. FUEL UNDER
THIS AMOUNT OF PRESSURE CAN PENETRATE
SKIN CAUSING PERSONAL INJURY OR DEATH.
INSPECT FOR HIGH — PRESSURE FUEL LEAKS
WITH A SHEET OF CARDBOARD. WEAR SAFETY
GOGGLES AND ADEQUATE PROTECTIVE CLOTH-
ING WHEN SERVICING FUEL SYSTEM.
CAUTION: The high-pressure fuel lines cannot con-
tact each other or other components. Do not
attempt to weld high-pressure fuel lines or to repair
lines that are damaged. If lines are ever kinked or
bent, they must be replaced. Use only the recom-
mended lines when replacement of high-pressure
fuel line is necessary.
High-pressure
fuel
lines
deliver
fuel
under
extremely high pressure from the high pressure
pump to the fuel injectors (Refer to 14 - FUEL SYS-
TEM - WARNING). The lines expand and contract
from the high-pressure fuel pulses generated during
the injection process. All high-pressure fuel lines are
of the same length and inside diameter. Correct high-
pressure fuel line usage and installation is critical to
smooth engine operation.
DIAGNOSIS AND TESTING - HIGH PRESSURE
FUEL LINES
Review the high pressure fuel system warning
before beginning service.(Refer to 14 - FUEL SYS-
TEM - WARNING). High-pressure fuel line leaks can
cause starting problems and poor engine perfor-
mance.
WARNING: DUE TO EXTREME FUEL PRESSURES,
USE EXTREME CAUTION WHEN INSPECTING FOR
HIGH-PRESSURE FUEL LEAKS. DO NOT GET YOUR
HAND NEAR A SUSPECTED LEAK. INSPECT FOR
HIGH-PRESSURE FUEL LEAKS WITH A SHEET OF
CARDBOARD. HIGH FUEL INJECTION PRESSURE
CAN CAUSE PERSONAL INJURY IF CONTACT IS
MADE WITH THE SKIN.
NOTE: Fuel Injector high pressure fuel lines must
be replaced when ever they are removed for ser-
vice.
Place the cardboard over the suspected high-pres-
sure fuel line(s). Move you hands away from the
area. Start the engine. TURN THE ENGINE OFF.
Inspect the cardboard for fuel spray (Fig. 11). If a
high-pressure line connection is leaking, counterhold
and tighten the connection to specification. Re-test as
indicated in the pervious steps. Replace damaged,
restricted or leaking high-pressure fuel lines with the
correct replacement line and perform the Fuel Sys-
tem Air Purge procedure (Refer to 14 - FUEL SYS-
TEM - STANDARD PROCEDURE).
14a - 12
FUEL DELIVERY
RG