TM-9-2320-260-34-1
TRUCK, 5-TON, 6X6, M809 SERIES (DIESEL)
TECHNICAL MANUAL; DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE; VOLUME 1 OF 2
JULY 1994
TM-9-2320-260-34-1 - Page 20 of 657
TM 9-2320-260-34-1
Table
2-1.
Mechanical Troubleshooting (Contd).
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
2. ENGINE CRANKS SLOWLY
Step 1. Perform electrical troubleshooting (TM 9-2320-260-20).
Step 2. Perform malfunction 1, step 5, malfunction 14, step 2, and malfunction 15.
END OF TESTING!
3. ENGINE CRANKS BUT WILL NOT START
Step 1. Check for defective fuel pump shutoff valves.
Step 2.
Step 3.
Step 4.
Step 5.
Replace fuel pump shutoff valves if defective (para. 5-15).
Check for broken fuel pump driveshaft.
a. Disconnect tachometer cable from fuel pump, crank engine (TM 9-2320-260-10), and
observe if driveshaft end in pump housing is rotating.
b. Replace fuel pump if driveshaft does not rotate (para. 5-13).
Check for correct fuel injector and valve adjustment.
Adjust fuel injectors and valves as necessary (para. 3-82, 3-83, or 3-84).
Check for dirty or damaged fuel injectors.
Replace fuel injectors if dirty or damaged (para. 5-6).
Check fuel pump operation.
Replace fuel pump if defective (para. 5-13).
END OF TESTING!
4. ENGINE STARTS, WON’T RUN
Step 1.
Step 2.
Check for low fuel flow.
Correct fuel line damage. Clean plugged or dirty fuel strainer (TM 9-2320-260-20).
Proceed to malfunction 21.
END OF TESTING!
5. ENGINE STOPS WHEN THROTTLE IS RETURNED TO IDLE POSITION
Step 1. Check if engine governor idle speed is set too low.
Adjust engine governor idle speed to specifications if incorrect (para. 5-25).
Step 2. Check fuel delivery system (malfunction 20).
END OF TESTING!
6. ENGINE HAS POOR ACCELERATION AND/OR LACK OF POWER
Step 1.
Step 2.
Step 3.
Step 4.
Check if engine maximum governed speed is set too low.
Adjust engine maximum governed speed to specifications if incorrect (para. 5-25).
Check fuel injector operation (malfunction 21).
Check engine valve train operation.
Adjust valves to specifications if incorrect (para. 3-82, 3-83, or 3-84).
Check engine cylinder compression (malfunction 12).
END OF TESTING!
2-6
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