The high pressure fuel lines are designed and manufactured to deliver fuel at injection pressure to the injectors.
The high pressure pulses will cause the lines to expand and contract during the injection cycle.
Shown here are the high pressure fuel lines for distributor type injection pump.
Shown here are the high pressure fuel lines for the Bosch P7100 in-line injection pump.
Do not weld or substitute lines; use only the specified part number for the engine.
The length, internal size and rigidity of the lines is critical to smooth engine operation. An attached metal tag is
used to identify each line with a part number.
Use cardboard to check for cracks and leaks. With the engine running, move the cardboard over the fuel lines
and look for fuel spray on the cardboard. Fuel leaks can cause poor engine performance.
It is normal to have entrapped air in the fuel lines after replacing the pump or the lines. Air in the lines will cause
the engine to run rough or produce a fuel knock.
Bleed the air from the high pressure line at the fitting that connects the injector. Bleed one line at a time until the
engine runs smooth.
If the air cannot be removed, check the pump and supply line for suction leaks.
