Manifold Absolute Pressure (Map) Sensor Test - Jeep 1987 Wrangler Workshop Manual

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THROTTLE BODY FUEL INJECTION SYSTEM
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1.4L 1983-1985
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TEST SEQUENCE
DESIRED RESULTS
POSSIBLE
ACTUAL RESULTS
DIAGNOSIS
C O R R E C T I V E ACTION
5. Push throttle in CLOSED
direction while pressing
exerciser switch in
RETRACT direction for 5
seconds.
ISA motor should continue
to retract until throttle lever
contacts with closed throttle
stop screw on TBI main
body.
IF, desired results were
obtained.
THEN, ISA motor is OK.
Check throttle control
system for freedom and
smoothness of movement.
Inspect throttle return
springs. Repair as
necessary. After repair,
perform test sequence
No.
6.
5. Push throttle in CLOSED
direction while pressing
exerciser switch in
RETRACT direction for 5
seconds.
ISA motor should continue
to retract until throttle lever
contacts with closed throttle
stop screw on TBI main
body.
IF, ISA motor did not
move.
THEN, ISA motor is
defective. Stop the
procedure. Replace the
ISA motor.
6. Move the ISA motor in
the EXTEND and
RETRACT direction 2 or
3 times. ALWAYS leave
ISA motor EXTENDED.
ISA motor should operate
smoothly and ratchet (click)
at end of EXTEND travel. It
should stop automatically at
end of RETRACT travel.
IF, the movement is
intermittant, slow, or
"gritty sounding".
THEN, replace ISA motor.
6. Move the ISA motor in
the EXTEND and
RETRACT direction 2 or
3 times. ALWAYS leave
ISA motor EXTENDED.
ISA motor should operate
smoothly and ratchet (click)
at end of EXTEND travel. It
should stop automatically at
end of RETRACT travel.
IF, desired results were
obtained.
THEN, ISA motor is OK.
Do not replace ISA motor.
6. Move the ISA motor in
the EXTEND and
RETRACT direction 2 or
3 times. ALWAYS leave
ISA motor EXTENDED.
ISA motor should operate
smoothly and ratchet (click)
at end of EXTEND travel. It
should stop automatically at
end of RETRACT travel.
IF, an idle problem still
exists.
THEN, further diagnosis
is necessary.
101769
Disconnect the ISA motor exerciser connector
from the ISA motor and from the battery.
Connect the original harness connector to the
ISA motor.
Install the air cleaner assembly (if it had been
removed).
Manifold Absolute Pressure (MAP) Sensor Test
I n s p e c t t h e M A P s e n s o r v a c u u m h o s e
connections at the throttle body and sensor.
Repair a s necessary.
Test the MAP sensor output voltage at the MAP
s e n s o r connector pin B ( a s marked on the
sensor body) with the ignition switch O N and the
engine O F F . Output voltage should be 4 -
5 volts.
NOTE:
T h e voltage should drop to 1.5 - 2.1 volts
with a hot neutral idle s p e e d condition.
T e s t E C U pin J 2 - 1 2 for the s a m e voltage
described a b o v e to verify the wire h a r n e s s
condition. Repair a s n e c e s s a r y .
T e s t the M A P s e n s o r supply voltage at the
sensor connector pin C with the ignition O N . T h e
voltage should be 5 volts ( ± 0 . 5 V ) .
The voltage should also be at pin J 2 - 2 of the
E C U wire h a r n e s s connector. Repair or replace
the wire h a r n e s s a s n e c e s s a r y .
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