TM 5-2420-230-24-2
B3.9 and B5.9 Series Engines
Fuel Flow (005-011)
Section 5 - Fuel System - Group 05
Page 5-15
During the test, record the following:
Ambient temperature
Humidity
Barometric pressure
Wind velocity
Wind direction.
NOTE: Avoid testing under any extreme conditions.
Fuel Flow (005-011)
Pressure Test (005-011-013)
Inspect to determine if the fuel transfer pump is delivering
fuel. Measure the output pressure at the inlet of the injec-
tion pump.
Fuel Transfer Pump Output Pressure at Rated Speed
kPa
psi
High-flow-automotive
172
MIN
25
Low-flow-industrial
83
MIN
12
If the required volume is not being delivered, measure the
transfer pump inlet restriction with a vacuum gauge be-
tween the transfer pump inlet and the supply line (4) from
the fuel tank.
Fuel Transfer Pump Inlet Restriction
kPa
in Hg
13.55
MAX
4
NOTE: Frequent fuel filter replacement to get full power
from the engine can indicate a worn fuel lift pump.
The pressure drop across the filter(s) will increase as the
filter removes contaminants from the fuel. A worn fuel lift
pump will have reduced capacity to force fuel through a
dirty filter. This can cause low engine power.
L-875
