Lumina L4-151 2.5L (1991)
Flange Mounted IAC Valve
REMOVAL:
1.
Verify that the ignition switch is in the OFF position.
2.
Disconnect the electrical connector.
3.
Remove the IAC valve assembly and O-ring, discard O-ring.
CAUTION: On IAC valves that have 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. Do Not soak the IAC valve in any liquid solvent or cleaner, as damage may result.
NOTE:
^
Clean the IAC valve gasket sealing surface, pintle valve seat, and air passage:
a.
Use carburetor cleaner to remove carbon deposits. Do Not use a cleaner that contains Methyl Ethyl Ketone. It is an extremely strong solvent,
and not necessary for this type of deposit.
b.
Shiny spots on the pintle or pintle seat are normal, and do not indicate misalignment or a bent pintle shaft.
c.
If the air passage has heavy deposits, remove the throttle body for complete cleaning.
^
If installing a new IAC valve, be sure to replace with an identical part. IAC valve pintle shape and diameter are designed for the specific
application.
INSTALLATION:
1.
If installing a new IAC valve:
a.
Measure the distance between the tip of the IAC valve pintle and the mounting surface.
b.
If greater than 28 mm, use finger pressure to slowly retract the pintle. The force required to retract the pintle of a new valve will not cause
damage to the valve.
2.
Install the IAC valve assembly with a new O-ring, and reinstall IAC valve assembly, making sure that attaching screws are coated with appropriate
thread locking compound.
3.
Connect the electrical connector.
4.
Reset the IAC valve pintle position:
^ The IAC valve will be reset by the computer when the vehicle speed exceeds 43 MPH while the engine speed is above 2000 RPM or when the
diagnostic test connector is grounded when the engine RPM is above 2000 RPM.
5.
Test drive the vehicle and check for proper idle operation.
