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

  TM-9-2320-280-20-1 - Page 196 of 888

Model Pump P/N (NSN)
Serial Number Break
Original P/N
New P/N (NSN)
DB2829-4523
7539307
23122 or 28396
DB2829-4879
80644583
23122 or 28396
DB2831-5149
776848
29124
DB2831-5149
776848
29124
TM 9-2320-280-20-1
REFERENCE INFORMATION
FUEL SYSTEM
Change 2
2-109
Return lines should be inspected for kinks or
crushed lines or anything that might restrict
fuel flow.
Inspect fuel return check valve for any
restrictions. Replace valve (para. 3-35).
Replace fuel lines. Refer to (para. 3-25).
If you came here from the Startability Tests,
return to STEP 5, Page 2-44.
If you haven’t run the Startability Tests yet, go
to STEP 1, Page 2-42.
During high temperature and humidity, early model vehicles can experience difficulty starting while using
JP-8 fuel. High temperatures can cause restrictive clearances in some older fuel injection head and rotor
assemblies. The engine must be allowed to cool to allow adequate clearance of the pumping plungers to
ensure adequate fuel delivery for starting. If this condition persists, run the startability tests. If vehicle
passes all startability tests and troubleshooting procedures and still experiences difficulty in hot starting,
identify the fuel injection pump and serial numbers.
All fuel injection pumps with P/N DB2831-5209, NSN 2910-01-467-9029 incorporated the improved head
and rotor assembly, P/N 31506. If your serial number is less than shown in the Serial Number Break
Column of the table below, the manufacturer recommends the fuel injection pump to be replaced, tagged as
a “no hot restart” condition, and forward for rebuild. Notify direct support maintenance.


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