INSTALLATION
(1) Positon the pr essu re sen sor in th e air clea ner
cover an d insta ll t he fasten ers (Fig. 22).
(2) Connect the electr ical connect or (Fig. 22).
(3) Connect the n egat ive batt ery cable.
MANIFOLD AIR FLOW (MAF)
SEN SOR
DESCRIPTION
The Mass Air Flow (MAF) Sensor is loca ted in the
air intake port between t he air filt er and the turbo-
charger (F ig. 23). The MAF sensor uses sem iconduc-
tor techn ology thr oughout, and is used to ca lculate
the air ma ss flowing past it per time unit. This m ass
is important for determinin g th e exh aust gas recircu-
lat ion ra te. Th e MAF sensor sends a corresponding
signal to t he ECM, wh ich evaluat es the sign al to
adju st t he exhau st gas recircu lation valve.
OPERATION
The E CM uses the m ass air flow (MAF) sensor to
measu re air density. The tem perature resistor located
at t he front of th e MAF sensor m easures t he t emper-
ature of t he inlet air. By varying the voltage, th e
electronic circuit regulates the temper ature of the
heat ing resistor in the r ear so that it is 320° F
(160°C) h igh er t han the tem perature of the inta ke
air. The tem per atu re at t he h eating resist or is mea-
su red by a sensor resist or in-between .
Because the incoming air h as a cooling effect, the
grea ter t he amount of air th at flows in, th en th e
higher the volta ge of the heat ing resistor. The hea t-
ing resistor is th erefore a mea su re of ma ss of air
flowing past. If a temper ature change occurs a s a
result of a in crease or redu ction of air flow, the E CM
correct s t he voltage at the heat ing resist or u ntil th e
temper ature differ ence is a gain achieved. This con -
trol voltage is use by the ECM as a unit measu re for
metered air mass.
REMOVAL
(1) Disconn ect the n egat ive battery cable.
(2) Detach th e a ir hose at the Man ifold Air Flow
(MAF) sensor
(3) Unplug the MAF wiring har ness connector.
(4) Remove th e screws r etaining the MAF sensor
to the a ir cleaner housing, a nd rem ove MAF sen-
sor.
Fig. 22 AIR CLEANER HOUSING
1 - AIR FLOW SENSOR
2 - GASKET
3 - AIR INTAKE HOSE
4 - AIR CLEANER HOUSING
5 - AIR CLEANER ELEMENT
6 - AIR INTAKE PRESSURE SENSOR
7 - AIR CLEANER HOUSING COVER
Fig. 23 MASS AIR FLOW (MAF) SENSOR
14 - 44 FUEL INJECTION VA
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