M2/M3 BFV ENGINE STARTING/CHARGING SYS - OD1603 - LESSON 1/TASK 1
Detecting the Malfunction: STARTER FAILS TO CRANK ENGINE. The following is
a typical procedure that unit maintenance personnel would follow in troubleshooting
and isolating the cause of the specific starting/charging system malfunction:
STARTER FAILS TO CRANK ENGINE.
Move the MASTER POWER switch (1)(figure 1 on the following page) to the
ON position. At this time, the volt gage indicator (2) should be pointing either
to the yellow or green zone. Upon checking, it is noticed that the indicator is in
the yellow zone.
Since the volt gage indicator is in the yellow zone, move the ENGINE
ACCESSORY switch (3) to the ON position.
Also move the GEAR SELECTOR (4) to the
START position for 5 seconds and release.
The starter should have cranked the
Do not hold the GEAR SELECTOR in the START position for
more than 30 seconds or the starter will be damaged.
If the starter did not turn the engine, move the ENGINE ACCESSORY
switch (3) to the OFF position. Also, move the MASTER POWER switch (1) to the OFF
Then connect the STE-M1/FVS (VTM only) to the distribution box (5) by
installing plug W1P2 (6) to jack 1A1J14 (DCA 3) (7). Afterwards, Test Number 90,
STARTER CURRENT DRAW, described in TM 9-2350-252-20-1-1, should be performed.
Test Number 90 revealed a current draw exceeding 650 amperes. This is
an indication that the battery has sufficient electric power for the starter to
crank the engine and that the connection between the battery and starter is not
Now the STE-M1/FVS (VTM only) is disconnected from the distribution
box. Next, the power unit (engine)(8)(figure 2 on page 10) should be removed from
the BFV as described in TM 9-2350-252-20-1-3.