a. An adequate fuel supply is the first and foremost item that must be
present and is the first preliminary check to make. The APU stores the fuel
supply in the main fuel tanks of the M992 CAT.
Although a check of the
vehicle fuel gage is the recommended method for checking fuel supply, an
actual check of the fuel level in the vehicle fuel cells is the surest
method of determining if an adequate fuel supply is present. If fuel levels
are low or if tank is empty, fill the tanks in accordance with TM 9-2350-
b. The second preliminary step to take when the engine cranks but fails
APU compartment side door as shown in Item 1, Figure 3.
Once you gain
access to the APU air cleaner, you are ready to perform the disassembly
process and determine if filters are dirty or clogged, or if air intake
system is restricted.
Refer to Figure 7 and follow these disassembly and
assembly steps for the APU air cleaner:
With the APU compartment side door in the open position, reach
into the APU compartment and loosen the air filter housing clamp
(Item 1) to remove the dust cap (Item 2).
Now remove the baffle (Item 3) from the dust cap (Item 4).
the dust cap and reinstall the dust cap into the baffle.
Begin removal of the filter element by removing the wing nut,
housing (Item 7).
the parts supply.
If the element is dirty or clogged, clean the element with low-
pressure compressed air directed to the inside portion of the
element. Excessive air pressure will cause damage to air cleaner
element or injury to personnel.
Compressed air used for cleaning purposes must not
exceed 30 psi. Use only with effective chip-guarding