Reverse Delay - Jeep J-10 Series 1982 Technical & Service Manual

1K-8 EXHAUST SYSTEMS
REVERSE DELAY-^^"!
jr CTO VALVE ^^"" ^^"** 0
VACUUM <CC$f^ ^^^^ \
TWO-WAY DELAY'*':
SWITCH
ASSEMBLY
AIR INJECTION
MANIFOLD
CHECK VALVE
AIR INJECTION
TUBE TO CONVERTER
MANIFOLD
VACUUM
4 SOURCE
- UPSTREAM
0/ SOLENOID
0
DIVERT
SOLENOID
*Q
AIR PUMP
90599B
Fig. 1K-10 Dual Air System—Six-Cylinder Engine
The pump is designed for long life and is serviceable
only by replacement. Do not remove the rear housing
cover for any reason. The internal components of the
pump are not serviceable.
The aluminum housing has cavities for air intake,
compression and exhaust and a bore for enclosing the
front bearing. The housing also includes cast metering
areas that reduce the noise of intake and compression.
Mounting bosses are located on the housing exterior.
NOTE: The pressure relief valve is located within the
diverter valve assembly. If defective, replace the di
verter valve assembly.
The front bearing supports the rotor shaft. The bear
ing is secured in position by plastic injected around
grooves in the housing and outer bearing race.
The rear cover supports the vane pivot pin, rear inner
bearing face and exhaust tube. Dowel pins pressed into
the housing correctly position the end cover, which is
fastened by four screws.
The rotor positions and drives the two vanes. A
stamped steel liner supports the carbon shoes and shoe
springs that seal the vanes and rotor. The two plastic
vanes are molded to hubs that support the bearings,
which rotate on the pivot pin. The pulley drive hub is
pressed onto the rotor shaft, and threaded holes in the
hub provide for attachment of the pulley.
Operation
The pump vanes are located 180° apart and rotate
around the pivot pin, which is located on the centerline
REAR COVER
HOUSING
VENT HOLE
(DO NOT OIL)
FILTER FAN
ROTOR SHAFT AND
DRIVE HUB
42007
Fig. 1K-11 Air Pump
of the pump housing. The rotor that drives the vanes
rotates off the centerline of the pump housing. This
creates changes in the distance between the outside of
the rotor and the inner wall of the pump housing during
rotor rotation. As the leading vane moves past the in
take opening, it is moving from a small area to a large
area. This creates a partial vacuum that forces air to
enter the pump. As the vanes and rotor continue to
rotate, the trailing vane passes the intake and traps the
air between the vanes. The vanes and rotor move the air
into a smaller area to compress it. Compression contin
ues until the leading vane passes the exhaust opening.
There the compressed air passes out of the pump to be
either distributed or vented.
Noise Diagnosis
The air pump is not completely noiseless. Under nor
mal conditions, noise will rise in pitch as the engine
speed increases. Allow for normal break-in wear of the
pump prior to replacement for excessive noise.
A chirping or squeaking noise normally originates
from vane rub in the housing bore and is noticeable at
low speed intermittently. Vane chirping is often elimi
nated at increased pump speeds or with additional wear-
in time. A chirping noise may also be caused by the drive
belt slipping on the pulley of a seized pump.
Bearing noise, a rolling sound noticeable at all
speeds, is easily distinguished from vane chirping. It
does not necessarily indicate bearing failure. If bearing
noise reaches an objectionable level at certain speeds,
the pump may have to be replaced.
Failure of a rear bearing is identified by a continuous
knocking noise and replacement of the pump is
required.