K 2500 Truck 4WD V8-350 5.7L (1988)
Idle Speed/Throttle Actuator - Electronic: Service and Repair
IAC Thread Mounted 10mm Pintle
NOTE: The Idle Air Control (IAC) valve is an electrical component and must not be soaked in any liquid cleaner or solvent. Otherwise damage
could result.
IMPORTANT:
All IAC valves on TBI 220 units (except on 7.4L engine) are thread-mounted and have a dual taper, 10 mm diameter, pintle. Any
replacement of the IAC valve must have the correct part number, with the appropriate pintle taper and diameter for proper seating of the
valve in the throttle body.
REMOVAL:
1.
Disconnect electrical connector.
2.
Remove IAC valve, use a 32 mm (1 1/4") wrench.
3.
Remove IAC gasket and discard.
CLEAN:
Clean old gasket material from surface of throttle body assembly to insure seal of new gasket.
Idle Air Control Valve Pintle Retraction (Manually)
NOTE: If the IAC valve was removed during service, its operation may be tested electrically with the IAC/ISC Motor Tester (J-37027 or BT-8256K).
Before installing a IAC valve, measure the distance between the tip of the valve pintle and the mounting surface. If the dimension is greater
than 28.0 mm (1.10 inches), the valve pintle must be retracted to prevent damage to the valve. This may be done electrically using an
IAC/ISC Motor Tester or manually by exerting firm pressure, as shown in the illustration, with a slight side to side movement on valve pintle
to retract it.
IMPORTANT:
No physical adjustment of the IAC valve assembly is required after installation. The IAC valve pintle is reset by turning the ignition
"ON" for ten seconds and then "OFF". The ECM then resets the pintle to the correct position. Proper idle regulation should result.
INSTALLATION:
1.
Install the IAC valve into the throttle body with new gasket.
NOTE: New IAC valves have been reset at the factory and should be installed in the throttle body in an "as is" condition, without any adjustment.
Tighten IAC valve assembly to 18.0 Nm (13.0 lb.ft)