Air Intake System

Maintenance of the M88A1
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37

Air Intake System. This system enables the engine to take in ambient

air containing the oxygen necessary for proper combustion of the fuel within

the cylinders.

The following subparagraphs provide a listing and brief

explanation of each component of this system.

(1) Air Cleaner.

Two dry-type air cleaners (figure 17, view A, on

the following page), mounted in the right and left rear of the crew

compartment, filter the intake air for the main engine. A damper control,

mounted on each air cleaner, is used to select air intake from either the

crew compartment or from outside the vehicle.

(2) Air Filter Restriction Gage. A restriction gage is located above

each air cleaner (figure 17, view B). It reads green when the air cleaner

is clean. As the filter becomes restricted, a red sleeve (2) begins to drop

into view. When the red sleeve fully covers the green, the air flow through

the filter is at maximum restriction and the filter element needs cleaning.

(3) Intake Hoses. Intake hoses (figure 18, on page 40), mounted on

each side of the engine, connect the air cleaners with the engine air intake

manifolds and provide the clean air with a passage from the air cleaner to

the engine.

(4) Manifold Air Induction Heater System (figure 19 on page 41).

Each intake manifold, which distributes supercharged air into each bank of

cylinders, is equipped with an electrically ignited intake manifold heater

(1) (figure 19).

The heater is used to facilitate engine starting during

cold weather. The purge pump, next to the operator's seat, is operated to

obtain 90 psi of pressure in the manifold heater fuel lines. Operation of

the heater switch on the purge pump handle energizes the manifold heater

fuel inlet solenoid valve (2) to allow fuel flow to the heater nozzle (2.1).

The heater switch also energizes the high tension coil (3) creating an

electrical spark in the manifolds, thereby igniting the sprayed fuel.