TM 5-3805-280-24-2
Fuel System Operation and Tests
DIAGNOSE FUEL SUPPLY PUMP MALFUNCTIONS--IN-LINE INJECTION PUMP
115
41
IMPORTANT: Visually inspect the fuel inlet fitting
and pump filter for possible plugging
before disassembling to determine
cause of malfunction.
Symptom
Problem
Solution
Low Supply Pump Output
Restriction at fuel inlet fitting.
Thoroughly clean fuel tank, lines,
Pressure or Pump Not
filters, and inlet fitting.
Functioning Correctly
Hand primer not screwed down tight,
Advise customer to tighten hand
allowing dirt to enter hand primer
primer after use.
plunger chamber.
Worn or pitted valves caused by
Replace valves as required.
foreign material lodging in valve.
Missing or broken spring(s).
Replace spring(s).
Broken spindle.
Replace pump.
Out of fuel.
Add fuel to fuel tank.
Fuel shut off at tank.
Open fuel shut-off valve.
Restricted fuel line.
Clean as required.
Air leak in fuel line between pump
Repair as required.
and tank.
Loose or damaged fuel line
Repair.
connections.
Hand primer left in upward position.
Bleed fuel system, gently push hand
primer down and tighten securely.
Worn or damaged valve assemblies.
Repair or replace.
Broken valve spring(s).
Repair or replace.
Diesel Fuel Leaking Into Injection
Worn spindle and/or pump housing.
Replace pump.
Continued on next page
RG,115,JW7704 1924NOV971/2
13-568