1999 Chevy S-10 how to change the IAC Valve on Chevy 99 S-1

REMOVAL PROCEDURE

CAUTION: Refer to Battery Disconnect Caution in Service Precautions.

1.Disconnect the negative battery cable.
2.Disconnect the IAT sensor harness connector.
3.Disconnect the breather tube from the air cleaner outlet duct.
4.Remove the wing nut retaining the air cleaner outlet duct.
5.Loosen the clamp on the outlet of the MAF sensor.
6.Lift the air cleaner outlet duct from the throttle body and remove the assembly from the MAF sensor.
7.Disconnect the IAC valve harness connector.
8.Remove the IAC valve mounting screws.
9.Remove the AC valve and O-ring from the throttle body assembly.

CLEANING AND INSPECTION PROCEDURE

NOTE: If the IAC valve has been in service: DO NOT push or pull on the IAC valve pintle. The force required to move the pintle may damage the threads on the worm drive. Also, DO NOT soak the IAC valve in any liquid cleaner or solvent, as damage may result.

1.Clean the AC valve O-ring sealing surface, pintle valve seat, and air passage.
**Remove excess carbon deposits with a small amount of carburetor cleaner on a parts cleaning brush. Follow any instructions on the cleaner container regarding cleaner usage.
**Do not use a cleaner containing an extremely powerful solvent such as methyl ethyl ketone.
**Shiny spots on the pintle and seat do not represent a bent or misaligned pintle shaft.
**If heavy deposits are present in the air passage, remove the throttle body for a complete cleaning.
IMPORTANT : Do not reuse the original O-ring.
Replace the IAC valve O-ring.

INSTALLATION PROCEDURE

NOTE: The IAC valve may be damaged it installed with the cone (pintle) extended more than 28 mm (1-1/8 in) . Measure the distance that the valve is extended before installing a new valve. The distance from the idle air control valve motor housing to the end of the idle air control valve pintle should be less than 28 mm (1-1/8 in) . Manually compressing the pintle until the extension is less than 28 mm (1-1/8 in) .

IMPORTANT : Use an identical part when installing a new Idle Air Control (IAC) valve. The IAC valve pintle shape and dimensions are designed for specific applications.

1.On a new IAC valve, measure the distance between the IAC valve pintle and mounting flange. Use finger pressure to slowly retract the pintle if the distance is more than 28 mm (1-1/8 in) .
2.Lubricate the IAC valve O-ring with clean engine oil.
3.Align the flange holes with the mounting holes on the throttle body assembly.
4.Insert the IAC valve through the O-ring into the throttle body assembly.

NOTE: Refer to Fastener Notice in Service Precautions.

IMPORTANT : The screws used to attach the IAC valve are coated with thread locking adhesive. Clean the attaching screw threads and apply thread locking material GM P/N 1052624 or equivalent.

5.Install the IAC valve mounting screws. Tighten Tighten the screws to 3 N.m (27 lb in) .
6.Connect the IAC valve harness connector.
7.Install the air cleaner outlet duct.
8.Tighten the air cleaner outlet duct wing nut.
9.Secure the air cleaner outlet duct to the MAF sensor. Tighten Tighten the air cleaner outlet duct clamp to 4 N.m (35 lb in) .
10.Connect the breather tube to the air cleaner outlet duct.
11.Connect the IAT sensor connector.
12.Connect the negative battery cable.
13.Reset the IAC valve pintle position.

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