TM 5-2420-230-24-2
B3.9 and B5.9 Series Engines
Fuel Lift Pump (005-045)
Section 5 - Fuel System - Group 05
Page 5-79
Tachometer, Part No. 3377462
Disconnect the fuel shutdown solenoid wire, and measure
the engine cranking speed with a handheld tachometer
Cummins Part No. 3377462.
CAUTION
Leave the shutdown solenoid disconnected for the fol-
lowing check.
Disconnect the output pressure line from the fuel transfer
pump, and run it into a container.
Measure the fuel transfer pump flow volume while cranking
the engine with the starter for 30 seconds.
Use the chart in the illustration to find the correct flow
volume specification for the diaphragm fuel transfer pump.
Draw a straight vertical line above the measured
cranking rpm
Draw a straight horizontal line from the measured
flow volume to the engine cranking rpm vertical line
to find the intersection point
Any intersection point above the required flow line
indicates an acceptable flow
Any intersection point below the required flow line
indicates unacceptable flow and a defective pump
or too much line restriction.
For example, if cranking speed of the engine is 230 rpm at
a flow volume of 260 ml [8.8 oz], this would indicate a good
pump.
For example, if cranking speed of the engine is 290 rpm at
a flow volume of 240 ml [8.1 oz], this would indicate a bad
pump.
L-939
