TM 5-3805-293-23-1
0011
Table 1. Engine Troubleshooting Procedures for the 120M Motor Grader - Continued.
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
N OT E
9. Engine Misfires, Runs
Rough, or is Unstable
If the fault is intermittent an cannot be duplicated, refer to
d
Troubleshooting, Intermittent Low Power or Power Cutout Malfunction
17 in this work package.
If the fault only occurs under cerain conditions, test the engine under
t
those conditions. Examples of certain conditions are high rpm, full load
and engine operating temperature. Troubleshooting the symptoms
under other conditions can give misleading results.
Active Event or Diagnostic Fault
1. Connect MSD (WP 0006). Select
Code - Troubleshoot fault codes (WP
Engine ECM C6.6 120M and
check for any active event or
diagnostic fault codes.
Air Inlet System is Blocked or Dirty
2. Inspect air inlet system for
- Clean and remove blockage from air
damage, blockage, and
cleanliness (WP 0037).
inlet system components (WP 0037).
Air Inlet System Components are
Damaged - Replaced damaged
components (WP 0115, WP 0078, and
WP 0103).
3. Visually check the fuel tank for
Fuel Low - Fill fuel tank (TM 5-3805-
fuel (TM 5-3805-293-10).
293-10).
4. Perform Fuel Quality Test (WP
Fuel System is Contaminated -
0035).
Drain fuel (WP 0229), replace primary
fuel filter (WP 0174), replace
secondary fuel filter (WP 0073), and
fill with correct fuel (TM 5-3805-293-
10) for machine operation.
5. Perform Fuel System Inspection
Fuel Rail Lines Leaking - Replace
(WP 0035).
fuel rail lines (WP 0072).
Low Pressure Fuel Lines Leaking -
Tighten lines (WP 0173).
Low Pressure Fuel Lines
Restricted/Damaged - Replace low
pressure fuel line (WP 0173).
Primary Fuel Filter and Water
Separator Damaged or
Contaminated - Replace primary fuel
filter and water separator (WP 0174).
Secondary Fuel Filter and Water
Separator Damaged or
Contaminated - Replace secondary
fuel filter (WP 0073).
0011-10
