TM 9-2320-272-24-1
Table 2-2. Mechanical Troubleshooting (Contd).
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
7. ENGINE MISFIRES DURING OPERATION
NOTE
If STE/ICE is available, perform NG90 - Governor/Power Test
Fault Isolation (para. 2-24).
Step 1. Perform malfunction 4, steps 1 and 2.
Step 2. Check accelerator linkage and modulator cables for proper operation and adjustment.
a. If accelerator linkage does not operate properly, adjust or replace as necessary
(para. 3-42 or 3-43).
b. Replace modulator cable if binding, broken, or sticking (para. 3-145).
c. If not corrected, notify DS maintenance.
END OF TESTING!
8. ENGINE IDLE ROUGH, ERRATIC (M939A2 ONLY)
Check for loose, plugged, or cracked injector tubes.
a. If loose, tighten injector tubes.
b. If cracked, replace (para. 3-19) (M939A2 only).
WARNING
Eyeshields must be worn when cleaning with compressed air.
Compressed air source will not exceed 30 psi (207 kPa). Failure to
do so may result in injury to personnel.
c. If plugged, remove and clear tubes with compressed air .
d. If not corrected, notify DS maintenance.
END OF TESTING!
9. POOR ACCELERATlON AND/OR LACK OF POWER
Step 1. Perform malfunction 4.
Step 2. Inspect accelerator pedal and throttle lever for full travel.
Adjust accelerator pedal and throttle lever travel (para. 3-42 or 3-43).
NOTE
Perform steps 3 through 7 for M939A2 series vehicles.
Step 3. Check Air Fuel Control (AFC) tube for leaks and/or restrictions.
a. If loose, tighten fittings.
b. If restricted, replace AFC tube if necessary (para. 3-18).
Step 4. Check for air leaks.
a. Check crossover tube and aftercooler for leaks.
b. Tighten all hose clamps.
c. Replace aftercooler gasket (para. 3-76).
d. Check for exhaust leaks at turbocharger and exhaust manifold. If exhaust leaks are
present, notify DS maintenance.
e. Replace turbocharger gasket (para. 3-21).
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