B3.9 and B5.9 Series Engines
Section 6 - Injectors and Fuel Lines - Group 06
To find which cylinder is misfiring, operate the engine and
loosen the fuel line nut at one injector, and listen for a
change in engine speed.
NOTE: A drop in engine speed indicates the injector was
delivering fuel to the cylinder.
NOTE: Be sure to tighten the fuel line nut before proceed-
ing to the next injector.
Check each cylinder until the malfunctioning injector is
Remove the malfunctioning injector to test or replace it.
If the engine continues to misfire after replacing the injec-
tor, check for leaks in the high-pressure line. Also, check for
a defective delivery valve that lets the fuel drain back into
the injection pump.
Check for an extra copper sealing washer on the injector.
Carbon buildup in the orifices in the nozzle will also cause
low power from the engine. Remove and check the spray
pattern, or replace the injectors.