TM 5-3805-260-24
2.
MISFIRING OR RUNNING ROUGH (CONT.)
Cause
Correction
Air In The Fuel System
Find the air leak in the fuel system and correct it. Loosen each fuel line nut at the
injection pumps and open the manual bleed valve. Loosen the bolts that hold the
torque spring or stop bar cover. This will let out any air that is in the governor
housing. After all air is out of fuel system, tighten bolts that hold torque spring or
stop bar cover. Tighten fuel line nuts according to the SPECIFICATIONS. Close
manual bleed valve.
Leak or Break in Fuel Line
Install a new fuel line.
Between Injection Pump and
Injection Valve
Wrong Valve Clearance
Make adjustment according to Testing and Adjusting.
Defect in Fuel Injection
Run engine at rpm that gives maximum misfiring or rough run
Nozzle
ning. Then loosen a fuel line nut on the injection line for each cylinder, one at a
time. Find the cylinder where loosening the fuel line nut does not change the way
the engine runs. Test the fuel injection nozzle for that cylinder. Install new parts
where needed.
Wrong Fuel Injection Timing
Make adjustment to timing.
3. STALL AT LOW RPM
Cause
Correction
Fuel Pressure is Low
Make sure there is enough fuel in the fuel tank. LIook for leaks or bad bends in the
fuel line between fuel tank and fuel transfer pump. Look for air in the fuel system.
Check fuel pressure. The outlet pressure of the fuel transfer pump at full load
speed is 30 + 5 psi (205 + 35 kPa).
If fuel pressure is lower than above pressure, install a new fuel filter element.
Inspect the bypass valve for free movement. Install a new bypass valve if
necessary.
Idle rpm Too Low
Make adjustment to governor so idle rpm is the same as given in the RACK
SETTING INFORMATION.
Defect in Fuel Injection
Install a new fuel injection nozzle.
Nozzle
Wrong Valve Clearance
Make adjustment according to Testing and Adjusting.
Spring for Dashpot
Install spring correctly.
Governor Installed Wrong
(Cont. next page)
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