ARMY TM 9-2815-259-24
AIR FORCE TO 38G1-125-2
MARINE CORPS 09249A/09246A-24
c. Measure blow-by over a period of 5 minutes. Multiply figure obtained by 12 (hourly rate). Maximum
allowable blow-by is 600 cu ft/h (17 m3/h).
d. If blow-by is lower, there probably is no undue wear between piston rings and liners. If blow-by is
higher, there could be excessive wear between piston rings and liners, resulting in loss of engine
INTAKE MANIFOLD PRESSURE CHECK.
a. Remove plug (6, Figure 3-7) from intake manifold and connect suitable gage to intake manifold.
b. Run engine to bring up to normal operating temperature. (From a cold start, operate engine 10 to 15
Engine speed and load should be stabilized before taking readings on
gage. Be sure that gage works properly.
Pressure checks are only a guide to determine if there is an engine
problem (valve leakage, defective nozzles, etc.). Low readings are not a
valid reason for increasing injection pump fuel delivery. Pump
adjustment should be within specification.
c. Observe pressure reading on gage. Reading should be at least 9 psi (60 KPa)/0.6 bar) when engine is
developing rated power at full load rated speed. Shut down engine.
d. If boost pressure is too high, remove and test fuel injection pump for high fuel delivery.
e. If boost pressure is too low, check for the following:
(1) Restricted air filter elements. Refer to TM 9-6115-671-14.
(2) Restricted fuel filter elements. Refer to TM 9-6115-671-14.
(3) Incorrect injection pump timing. Refer to paragraph 5.3.1.
(4) Exhaust manifold leaks. Refer to paragraph 3.10.2.
(5) Intake manifold leaks. Refer to paragraph 3.10.1.
(6) Faulty fuel transfer pump. Refer to paragraph 3.12.3.
(7) Low compression pressure. Refer to paragraph 3.7.1.
(8) Faulty fuel injection nozzles. Notify next higher level of maintenance, refer to paragraph 4.6.2.
(9) Carbon build-up in turbocharger. Notify next higher level of maintenance, refer to paragraph
(10) Turbocharger compressor or turbine wheel rubbing housing. Notify next higher level of
maintenance, refer to paragraph 4.4.1.