Oxygen Sensor And Closed Loop Test - Jeep 1987 Wrangler Workshop Manual

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ENGINES
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FUEL FEEDBACK SYSTEMS
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D I A G N O S T I C TEST 6
OXYGEN SENSOR AND CLOSED LOOP TEST
WITH ENGINE OFF, REMOVE AIR CLEANER AND PLUG
MANIFOLD V A C U U M HOSES.
START ENGINE A N D OPERATE UNTIL TEMPERATURE
GAUGE POINTER IS AT MIDRANGE (OR 4 MINUTES).
C O N N E C T P O S I T I V E P R O B E O F DIGITAL V O L T M E T E R (OR V O L T M E T E R WITH
G R E A T E R THAN 1 MEGOHM INPUT IMPEDANCE) T O PIN 8 AT H A R N E S S SIDE O F
MCU C O N N E C T O R AND NEGATIVE P R O B E TO PIN 20 O F C O N N E C T O R (GROUND).
I N C R E A S E ENGINE S P E E D T O APPROXIMATELY 1200 RPM AND MAINTAIN. C L O S E CHOKE
V A L V E AND O B S E R V E VOLTMETER. ( C L O S E V A L V E FOR AT L E A S T 15 S E C O N D S BUT DO
NOT E X C E E D 30 S E C O N D S . )
Y E S
OPERATE ENGINE FOR A MINIMUM OF 1 MINUTE.
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I N C R E A S E ENGINE S P E E D TO MORE THAN 1200 RPM.
HOLD THE CHOKE VALVE C L O S E D FOR AT L E A S T 20
S E C O N D S AND T U R N IGNITION O F F WITH V A L V E
C L O S E D .
CONT'D.
CONT'D
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