OM673L3 5/21
32
Troubleshooting
Figure 12:
M673 Fuel System.
BLEEDING THE FUEL SYSTEM
CAUTION: Escaping diesel fuel under pressure can penetrate skin causing serious personal injury.
Before disconnecting lines be sure to relieve all pressure. Before applying pressure, be sure all
connections are tight and lines, pipes and hoses aren't damaged. Fuel escaping from a very small hole
can be almost invisible. Use a piece of cardboard or wood, rather than hands, to search for suspected
leaks. If injured by escaping fuel, see a doctor at once. Serious infection or reaction can develop if
proper medical treatment isn't administered immediately.
1. The fuel system is self-bleeding. However, any system
may need manual bleeding when:
a. A new fuel filter is installed;
b. The engine has run out of fuel;
c. The fuel lines, injection pump or any other fuel
system component has been removed and installed.
2. Loosen bleed screw “A” (
Figure 12
) on top of the
filter. Pump hand primer “B” on fuel lift pump until
pure fuel (no bubbles) escapes from bleed screw “A”.
Tighten bleed screw “A”.
3. Loosen bleed screw “C”. Pump hand primer “B” on
fuel lift pump until pure fuel (no bubbles) escapes
from bleed screw “C”.
4. If the engine does not start after the above bleeding
process, loosen a fuel line at the injector. Crank the
engine until pure fuel escapes, then tighten the con-
nection. Do each line
one at a time.
5. After the engine has started, check for fuel leaks using
a piece of cardboard.
Updated 6-23-10
