Jeep 1987 Wrangler Workshop Manual page 1523

m G
THROTTLE BODY FUEL INJECTION SYSTEM
#i\ G
m G
1.4L 1983-1985
#i\ G
TROUBLE
CODE/CONDITION POSSIBLE CAUSE
CORRECTION
Idle speed erratic, low, or high
consistently.
1% motor inoperative.
No ECU output.
Throttle position incorrect.
ECU does not turn off after engine
shut down (Symptom: battery loses
charge with key off.)
MAP sensor voltage supply (ECU
Pin J2-2). Voltage should go
from 5V to zero within 30
seconds after key is turned off.
Refer to ISA Motor Diagnostic Test
using ISA motor exerciser tool AB.99.
Connect a test lamp from J1-C
to J1-D on the ECU. Remove the
ISC motor from the bracket and
close the CTS switch manually.
With the engine warmed-up and
at idle speed, manually open the
throttle to a speed well above
normal idle speed. The light
should flash. Close the throttle
so the speed drops well below
normal idle speed. The light
should flash.
Note: Improper handling of the
ISC motor outputs can result in
system damage. Never connect
to ground or the battery.
If the light flashes on both over
and under idle speed: Check the
wiring harness between the ECU
and the ISC motor for an open or
short circuit. Recheck the ISC
mojor function.
If the light fails to flash on
either over or underspeed:
Check the ECU with MS 1700
tester.
Check to ensure that the throttle
is resting on the switch at
normal idle. Connect a voltmeter
from D2 pin 13 to D1 Pin 3.
Should indicate ground potential
at a normal idle speed.
Check for air leaks into vacuum.
Check the closed throttle switch
using the test procedure.
Check coolant temperature
sensor. Refer to the test
procedure.
Check the starter motor relay for
a short circuit. With the key off,
check the relay for battery
voltage.
SEI
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