TM-9-2320-280-20-1
TRUCK, UTILITY: M998 SERIES
TECHNICAL MANUAL; UNIT MAINTENANCE; VOLUME 1 OF 3
JANUARY 1996
TM-9-2320-280-20-1 - Page 193 of 888
2-106
Change 2
B1
KNOWN INFO
ENGINE DOESN’T
STAY RUNNING
POSSIBLE PROBLEMS
FUEL PUMP
FUEL SUPPLY LINES
FUEL RETURN LINES
FUEL FILTER
FUEL
SOLENOID/WIRING
HIGH PRESSURE
SYSTEM
Go to B4,
page 2-108
TM 9-2320-280-20-1
FUEL SYSTEM
DIAGNOSTIC FLOWCHART
TEST OPTIONS
STE/ICE Test 90,
(page 2-751)
Multimeter
REASON FOR QUESTION
Current through the wire
quickly checks the integrity of
the fuel system wiring. The
normal reading will be about
1.3 to 1.5 amps.
KNOWN INFO
OTHER SYSTEMS
LISTED ABOVE OK
POSSIBLE PROBLEMS
FUEL PUMP
FUEL SUPPLY LINES
FUEL RETURN LINES
FUEL FILTER
FUEL
SOLENOID/WIRING
HIGH PRESSURE
SYSTEM
KNOWN INFO
FUEL PUMP OK
FUEL SUPPLY LINES
OK
FUEL FILTER OK
FUEL RETURN LINES
FUEL
SOLENOID/WIRING
HIGH PRESSURE
SYSTEM
POSSIBLE PROBLEMS
TEST OPTIONS
STE/ICE Test 24,
(page 2-738) Fuel Pump
Volume Test
REASON FOR QUESTION
Positive pressure and
volume indicate that fuel is
present and supply lines and
filter are not plugged. This is
a test of the lift pump.
TEST OPTIONS
Put the return line in a
suitable container and try
starting the engine.
REASON FOR QUESTION
A restricted fuel return line
will cause a pressure
imbalance in the pump and
prevent the engine from
running.
B3
B2
NO
YES
Go to N,
Page 2-132
B
From 2,
Page 2-96
Disconnect the glowplug
controller and wire 569B/569D
from the injector pump. Make
sure that wire 54A is properly
connected to the injector pump.
With the rotary switch in “RUN”
position, do you have at least 0.5
amps DC flowing through wire
54A?
Reconnect the above wires.
Check fuel pump pressure and
volume during cranking. Is
pump pressure greater than 3
psi (20.69 kPa) and fuel volume
at the injection pump inlet 1 pint
in 30 seconds?
Does the engine start and stay
running with the fuel return line
(the short rubber line at the
injector pump) disconnected?
NO
YES
Go to D,
Page 2-112
NO
YES
Go to I,
Page 2-126
!!
Back to Top
