B3.9 and B5.9 Series Engines
Section 6 - Injectors and Fuel Lines - Group 06
Failure of the needle valve to lift and close at the correct
time or needle valve stuck open can cause the engine to
misfire and produce low power. Fuel leaking from the open
nozzle can cause a fuel knock, poor performance, smoke,
poor fuel economy, and rough running.
Clean around the injectors.
Disconnect the high-pressure fuel supply lines.
Disconnect the fuel drain manifold.
When using solvents, acids, or alkaline materials for
cleaning, follow the manufacturer's recommendations
for use. Wear goggles and protective clothing to avoid
When rust has formed on the hold-down nut, the in-
jector can turn in the bore when the nut is loosened.
This can cause severe damage to the head by the in-
jector locating ball cutting a groove in the bore.
Soak the hold-down nut with a rust-penetrating solvent for
a minimum of 3 minutes.
Brass Drift Pin, Hammer
Hit the injector body with the drift pin to loosen any rust.