TM 5-3825-226-24
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 running.
Nozzle
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. Look 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 g iven 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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