ENGINE TROUBLESHOOTING
TM 9-2815-225-34&P · Work Package 0004 00
SCOPE
This Work Package (WP) contains troubleshooting information to diagnose and correct engine malfunctions for Big Cam I and Big Cam III engines. Use this information in conjunction with troubleshooting procedures in TM 9-2320-273-20 and TM 9-2320-273-34 for Big Cam I, and TM 9-2320-283-20 and TM 9-2320-283-34 for Big Cam III. For further engine troubleshooting information, refer to the Cummins Troubleshooting and Repair Manual, NT 855 Engines, Bulletin No. 3810298-00. Troubleshooting procedures are organized by malfunction, followed by a test or inspection to determine the corrective action required. Each step has a corrective action, along with appropriate WP references. Steps listed under each malfunction are in the order in which the causes are most likely to occur.
GUIDELINES
Observe the following guidelines when performing troubleshooting procedures.
1. Check all tags, service request forms, and vehicle logbooks for repair history. This may provide information as to the source of the problem.
2. Debrief the operator (if possible) for a general description of the problem, then attempt to verify the fault.
3. When troubleshooting, always check the easiest and most obvious things first. This simple rule saves time and trouble. For example, low power complaints are often the result of loose throttle linkage, dirty fuel, or clogged air filters, and excessive oil consumption is often the result of leaky gaskets or loose line connections.
4. Double-check before disassembly. The source of many engine problems can be traced to more than one part in a system. For example, excessive fuel consumption may not be caused by the fuel pump alone. Instead, the trouble could be a clogged air cleaner or a restricted exhaust passage causing severe back pressure.
Table 1. Engine Troubleshooting.
MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION
1. ENGINE WILL NOT a. Remove rocker covers and rotate
CRANK engine by attaching a socket and
breaker bar to accessory drive
nut.
b. Test for mechanical or hydraulic b. If valve fails to open or close,
seizure. manually open valve with 3/4-in.
wrench. If valve(s) are seized,
remove corresponding cylinder
head (WP 0011 00).
Remove fuel injectors
(WP 0011 00).
Turn engine over several times to
displace liquid from cylinders
through injector openings.
If engine can be turned freely
after all liquids have been
displaced, install injectors. If
engine cannot be turned over
freely by hand, disassemble
engine and replace defective parts.
c. Check for bent pushrod(s) and c. Replace pushrods and valves if
valve(s) not opening or closing. damaged.
2. ENGINE CRANKS a. Test for broken fuel gear pump a. Replace fuel gear pump drive
BUT FAILS TO START driveshaft. shaft if damaged (WP 0036 00).
b. Test for dirty or damaged b. Replace injectors (WP 0011 00
injectors. and WP 0043 00).
c. Test for defective fuel solenoid c. Replace fuel solenoid valve
valve. (WP 0034 00).
d. Test for faulty fuel pump. d. Replace fuel pump (WP 0010 00
(Disconnect fuel outlet hose; and WP 0040 00).
crank engine to see if fuel comes
out.)
e. Test for incorrect injector e. Adjust injectors (WP 0043 00).
adjustment.
f. Test for incorrect valve clearance. f. Adjust valve(s) (WP 0043 00).
g. Test for incorrect injector timing. g. Adjust injector system timing
(WP 0043 00).
3. ENGINE STARTS, a. Inspect for defective starter a. Replace starter pinion gear
MOTOR OPERATES pinion gear. (TM 9-2320-283-34).
BUT DOES NOT
ENGAGE THE b. Inspect for defective ring gear. b. Replace ring gear (WP 0007 00
RING GEAR and WP 0049 00).
Table 1. Engine Troubleshooting (Contd).
MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION
4. ENGINE STOPS a. Check if engine is overheated. a. See malfunction 6.
b. Check for loose fuel solenoid wire b. Replace fuel solenoid valve
and defective fuel solenoid valve. (WP 0033 00).
c. Check for faulty fuel pump. c. Replace fuel pump (WP 0010 00).
5. ENGINE FAILS TO STOP a. Check for stuck fuel solenoid a. Replace fuel solenoid valve
valve. (WP 0033 00).
b. Check for turbocharger oil seal b. Replace compressor oil seal
leak in compressor end. (WP 0026 00 and WP 0027 00).
6. ENGINE OVERHEATS Check for leaking or noisy water Repair water pump (WP 0041 00).
pump.
7. EXCESSIVE EXHAUST a. Check for incorrect injector a. Adjust injectors (WP 0044 00).
SMOKE adjustment.
b. Check for defective fuel b. Replace defective fuel injector(s)
injector(s). (WP 0011 00).
c. Check for blocked fuel return line c. Repair fuel return line
in fuel system. (TM 9-2320-283-20).
d. Check for improperly seated d. Reseat or replace valves
valves. (WP 0014 00).
e. Check for incorrect injection e. Adjust injection system timing
timing. (WP 0042 00).
8. LOW OIL PRESSURE a. Check pressure regulator a. Free up pressure regulator or
replace oil pump (WP 0010 00).
b. Check for spun camshaft b. Replace camshaft bushing
bushing. (WP 0013 00).
c. Inspect oil pump gasket. c. Replace gasket (WP 0023 00).
d. Check for worn camshaft. d. Replace camshaft (WP 0013 00).
e. Check for worn crankshaft. e. Replace crankshaft and install
new bearings (WP 0012 00).
f. Inspect main bearings. f. Replace main bearings
(WP 0012 00).
g. Inspect connecting rod bearings. g. Replace connecting rod bearings
(WP 0012 00).
h. Inspect oil pump gears. h. Repair oil pump (WP 0023 00).
i. Check for high oil temperature. i. Inspect and clean oil cooler
(WP 0021 00).
j. Check for worn crankshaft. j. Repair crankshaft (WP 0016 00).
Table 1. Engine Troubleshooting (Contd).
MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION
9. ENGINE KNOCKS a. Check for broken piston. a. Replace piston (WP 0018 00).
b. Check for broken injector cup. b. Repair injector (WP 0032 00).
c. Check for incorrect valve c. Adjust valves (WP 0043 00).
adjustment.
d. Check for incorrect injector d. Adjust injectors (WP 0043 00).
adjustment.
e. Check for loose connecting rod e. Tighten connecting rod capscrews
capscrews. to proper torque and check
bearings (WP 0042 00).
f. Check for worn connecting rod f. Replace connecting rod bearings
bearings. (WP 0012 00 and WP 0042 00).
g. Check for loose main bearing g. Torque main bearing capscrews
capscrews. (WP 0042 00).
h. Check for worn main bearings. h. Replace main bearings
(WP 0042 00).
i. Check for excessive crankshaft i. Check crankshaft end clearance
end clearance. (WP 0042 00).
j. Check for worn crankshaft. j. Replace crankshaft and install
new bearings (WP 0042 00).
k. Check for worn piston pins. k. Replace worn piston pins and
bushings or replace rods
(WP 0018 00).
l. Check for broken piston. l. Replace piston (WP 0018 00).
m. Check for incorrect injection m. Adjust injector system timing
timing. (WP 0041 00).
10. EXCESSIVE a. Check for incorrect valve and a. Adjust valves and injectors
FUEL CONSUMPTION injector adjustment. (WP 0043 00).
b. Check for excessive fuel pressure. b. Test and calibrate fuel pump
(WP 0044 00).
c. Check for restricted fuel drain. c. Repair fuel crossover tubes
(WP 0010 00).
d. Check for defective injector(s). d. Replace defective injector(s)
(WP 0011 00).
e. Check for leaking cylinder head e. Replace cylinder head gasket(s)
gasket(s). (WP 0011 00).
f. Check for incorrect injection f. Adjust injector system timing
timing. (WP 0043 00).
Table 1. Engine Troubleshooting (Contd).
MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION
11. EXCESSIVE OIL a. Check for external leaks. a. Tighten external oil connections
CONSUMPTION and replace damaged gasket(s).
b. Check turbocharger oil seals. b. Replace turbocharger oil seals
(WP 0026 00 and WP 0027 00).
c. Check for worn, stuck, or broken c. Replace piston rings
piston rings. (WP 0018 00).
d. Check for worn piston(s) and d. Install new pistons and cylinder
cylinder liner(s). liners (WP 0012 00).
e. Check for cracked piston. e. Replace damaged piston
(WP 0012 00).
12. EXCESSIVE ENGINE a. Check for loose or worn engine a. Replace mounts
VIBRATION insulators. (TM 9-2320-283-34).
b. Check for loose or worn cab b. Replace insulators
insulators. (TM 9-2320-283-34).
c. Check for burned valves. c. Replace valves (WP 0014 00).
d. Check for excessive flexdisk and d. Correct flexdisk and ring gear
ring gear runout. runout (WP 0042 00).
e. Check for loose flexdisk and ring e. Tighten flexdisk and ring gear
gear mounting screws. mounting screws (WP 0042 00).
f. Check for loose flywheel housing f. Tighten flywheel housing screws
screws. (WP 0042 00).
g. Check for misalignment of g. Align flywheel housing
flywheel housing. (WP 0042 00).
h. Check for unbalanced flexdisk h. Replace the flexdisk and ring
and ring gear. gear (WP 0013 00 and
WP 0042 00).
i. Check for loose vibration damper. i. Tighten vibration damper screws
(WP 0042 00).
j. Check for unbalanced vibration j. Install new vibration damper
damper. (WP 0042 00).
k. Check adjustment of valves and k. Adjust valves and injectors
injectors. (WP 0043 00).
l. Check timing for air compressor. l. Adjust air compressor timing
(WP 0042 00).
m. Check for incorrect injection m. Adjust injector system timing
timing. (WP 0042 00).
Table 1. Engine Troubleshooting (Contd).
MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION
12. EXCESSIVE ENGINE n. Check for excessive flywheel n. Correct flywheel runout
VIBRATION (Contd) runout. (WP 0042 00).
o. Check for unbalanced flywheel or o. Replace flywheel (WP 0042 00)
one or more injectors not or replace faulty injectors
performing properly. (WP 0043 00).
13. ENGINE a. Check fuel pump idle setting. a. Adjust idle setting (WP 0044 00).
WILL NOT IDLE
b. Check for improperly assembled b. Assemble governor spring
governor spring. correctly (WP 0037 00).
c. Check for stuck governor spring c. Free governor spring plunger
plunger. (WP 0037 00).
d. Check for plugged governor d. Clean governor barrel
barrel. (WP 0037 00).
14. FUEL LEAKS a. Check for faulty seals and a. Install new seals and O-rings
AT FUEL PUMP O-rings in fuel pump. (WP 0033 00).
OR INJECTOR
b. Check for mutilated injector b. Replace injector mounting
O-rings. O-rings (WP 0039 00).
c. Check for faulty fuel filter c. Replace gasket (WP 0039 00).
gasket.
15. ENGINE DOES NOT a. Check for damaged turbocharger. a. Repair turbocharger
DEVELOP FULL (WP 0026 00 and WP 0027 00).
POWER
b. Check for improperly adjusted b. Adjust valves and injectors
valves and injectors. (WP 0043 00).
c. Check for worn or scored fuel c. Repair fuel pump (WP 0033 00).
pump components.
d. Check for dirty fuel injector(s). d. Clean fuel injector(s)
(WP 0032 00).
e. Check for scuffed cylinder liners. e. Replace cylinder liners
(WP 0013 00).
f. Check for incorrect injection f. Adjust injection system timing
timing. (WP 0042 00).
g. Check for plugged electric shutoff g. Clean electric shutoff valve
(solenoid) valve. (solenoid) (WP 0034 00).
h. Check for plugged fuel pump h. Clean or replace fuel pump
throttle control shaft. throttle control shaft
(WP 0040 00).
i. Check for burned valves. i. Reface or replace valves and
valve seats (WP 0014 00).
j. Check for plugged Air Fuel j. Replace AFC breather
Control (AFC) breather (WP 0040 00).
(check valve).
Table 1. Engine Troubleshooting (Contd).
MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION
16. ENGINE MISSES OR a. Check for improperly adjusted a. Adjust valves and injectors
RUNS ERRATICALLY valves and injectors. (WP 0043 00).
b. Check injector for leaking middle b. Replace injector middle O-ring
O-ring. (WP 0032 00).
c. Check for damaged rocker arms. c. Replace rocker arms
(WP 0020 00).
d. Check for broken fuel injector
plunger spring. d. Replace fuel injector plunger
spring (WP 0032 00).
e. Check for broken or deformed
injector cup. e. Replace injector cup (WP 0032 00).
f. Check for plugged injector cup f. Clean injector cups
spray holes. (WP 0032 00).
g. Check for plugged metering or g. Clean fuel injectors
drain orifice in fuel injectors. (WP 0032 00).
h. Check for burned or excessively h. Reface or replace valves and
pitted valves. valve seat inserts (WP 0014 00).
i. Check for cracked or broken i. Replace damaged valve seat
valve seat inserts. inserts (WP 0014 00).
j. Check for incorrect injection j. Adjust injection system timing
timing. (WP 0043 00).
k. Check for leaking injector k. Replace injector sleeves
sleeves. (WP 0043 00).
17. EXCESSIVE a. Check for broken or worn gear a. Replace gears or units having
GEAR NOISE teeth. damaged teeth (refer to
WP 0013 00, WP 0017 00
and WP 0036 00).
b. Check for excessive gear b. Replace defective gears or shafts
backlash. (refer to WP 0042 00).
18. EXCESSIVE OIL LOSS a. Check for cracked or broken front a. Replace front gearcase cover
gearcase cover. (WP 0010 00 and WP 0045 00).
b. Check for defective seals and b. Replace faulty seals and gaskets
gaskets. as required.
c. Check for leaking rear cover oil c. Replace rear cover oil seal or
seal or gaskets. gaskets (WP 0013 00).
19. SLUDGE FORMATION Check for moisture in crankcase. a. Isolate the source and repair as
IN CRANKCASE required.
b. Inspect for tears on head gasket
cylinder openings.
Table 1. Engine Troubleshooting (Contd).
MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION
20. LUBRICATING OIL a. Check for moisture in crankcase. a. Isolate source and repair as
DILUTED required.
b. Check injector for damaged b. Inspect for tears at head gasket
O-ring. cylinder openings.
c. Check for defective injector(s). c. Replace injector O-ring
(WP 0032 00).
d. Check for broken piston. d. Repair injectors (WP 0032 00).
e. Check for cracked or broken e. Replace piston (WP 0018 00).
piston rings.
f. Replace broken piston rings
(WP 0018 00).
21. LOW COMPRESSION a. Check adjustment of valve and a. Adjust valves and injectors
injectors. (WP 0043 00).
b. Check for worn cylinder liners. b. Replace cylinder liners
(WP 0013 00).
c. Check for leaking cylinder head c. Replace gasket (WP 0011 00 and
gasket. WP 0043 00).
d. Check for worn piston rings. d. Replace piston rings
(WP 0018 00).
e. Check for incorrect timing. e. Adjust injection system timing
(WP 0043 00).
f. Check for valves not seating. f. Reface valves and seats
(WP 0014 00).
22. ENGINE OVERSPEED a. Check for improperly adjusted a. Adjust governor (WP 0038 00).
governor.
b. Check for defective governor or b. Repair governor or fuel injection
fuel pump. pump as necessary (WP 0033 00
and WP 0038 00).
END OF WORK PACKAGE
MAINTENANCE INSTRUCTIONS FOR ENGINE, DIESEL CUMMINS MODEL NTC-400
M915, M915A1, M915A4,
M916, M920 VEHICLES
Work Package Title Work Package/Page No.
Preventive Maintenance Checks and Services (PMCS) Introduction . . . . . . . . . . . . . . . . . . . . . . . . WP 0005 00-1 Preventive Maintenance Checks and Services (PMCS) Instructions . . . . . . . . . . . . . . . . . . . . . . . . WP 0006 00-1 Big Cam I Engine Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . WP 0007 00-1 Big Cam III Engine Removal . . . . . . . . . . . . . . . . . . . . . . . . . . WP 0008 00-1 Mounting Engine on Maintenance Stand . . . . . . . . . . . . . . . . WP 0009 00-1 Engine Accessories Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . WP 0010 00-1 Cylinder Head and Cylinder Head Components Removal . . . WP 0011 00-1 Cylinder Block Components Removal . . . . . . . . . . . . . . . . . . . WP 0012 00-1 Cylinder Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WP 0013 00-1 Cylinder Head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WP 0014 00-1 Vibration Damper and Crankshaft Pulley Cleaning and Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . WP 0015 00-1 Crankshaft Cleaning and Inspection . . . . . . . . . . . . . . . . . . . . WP 0016 00-1 Flexplate, Flywheel, Flywheel Housing, and Rear Cover Cleaning and Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . WP 0017 00-1 Pistons, Connecting Rods, and Bearings . . . . . . . . . . . . . . . . . WP 0018 00-1 Camshaft, Camshaft Followers, and Pushrods . . . . . . . . . . . . WP 0019 00-1 Rocker Levers and Rocker Lever Housing . . . . . . . . . . . . . . . . WP 0020 00-1 Oil Cooler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WP 0021 00-1 Oil Pan, Dipstick, Oil Suction Tubes, and Breather Tube . . . WP 0022 00-1 Oil Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WP 0023 00-1 Air Aftercooler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WP 0024 00-1 Exhaust Manifold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WP 0025 00-1 Turbocharger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WP 0026 00-1 Turbocharger HT-3B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WP 0027 00-1 Front Gear Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WP 0028 00-1 Accessory Drive and Accessory Drive Pulley . . . . . . . . . . . . . . WP 0029 00-1 Engine Retarder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WP 0030 00-1 Air Compressor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WP 0031 00-1 Fuel Injector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WP 0032 00-1 Fuel Pump Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WP 0033 00-1 Solenoid Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WP 0034 00-1 Fuel Damper and Head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WP 0035 00-1 Fuel Gear Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WP 0036 00-1 Fuel Pump Governor Spring . . . . . . . . . . . . . . . . . . . . . . . . . . . WP 0037 00-1 Fuel Pump Front Cover and Governor . . . . . . . . . . . . . . . . . . . WP 0038 00-1
Work Package Title Work Package/Page No.
Fuel Pump Main Housing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WP 0039 00-1 Fuel Pump Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WP 0040 00-1 Water Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WP 0041 00-1 Cylinder Block Components Installation . . . . . . . . . . . . . . . . . WP 0042 00-1 Cylinder Head and Cylinder Head Components Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WP 0043 00-1 Fuel Pump Testing and Calibration . . . . . . . . . . . . . . . . . . . . . WP 0044 00-1 Engine Accessories Installation . . . . . . . . . . . . . . . . . . . . . . . . WP 0045 00-1 Removing Engine from Maintenance Stand . . . . . . . . . . . . . . WP 0046 00-1 Engine Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WP 0047 00-1 Big Cam III Engine Installation . . . . . . . . . . . . . . . . . . . . . . . . WP 0048 00-1 Big Cam I Engine Installation . . . . . . . . . . . . . . . . . . . . . . . . . WP 0049 00-1 Big Cam III Modification Kit Installation Instructions . . . . . WP 0050 00-1 General Maintenance Instructions . . . . . . . . . . . . . . . . . . . . . . WP 0051 00-1 Illustrated List of Manufactured Items . . . . . . . . . . . . . . . . . . WP 0052 00-1 Torque Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WP 0053 00-1 Wear Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WP 0054 00-1