Engine Controls - Removal & Installation: Diagnosis Pontiac Sunfire I

Cleaning & Inspection

If using the original IAC valve, perform the following inspection and cleaning procedure

1. Clean the IAC valve sealing surface, pintle valve seat and air passage in the throttle body.
2. Whenever the air passages have heavy deposits, remove the throttle body for a complete cleaning. See «THROTTLE BODY»(ref-153402-S00734670642003040400000) .
3. The IAC valve may be cleaned by using a shop towel or small parts cleaning brush to remove heavy deposits.
4. Shiny spots on the pintle or seat are normal, and not an indication of a misaligned pintle shaft.
5. Check the IAC valve seal for cuts, cracks or distortion. Replace the IAC valve if the valve is damaged.

1. Compare the distance between the tip, or the pintle, and the mounting flange of the new and old IAC valves. Use finger pressure to slowly retract the pintle of the new valve to the distance of the old valve. This will not cause damage to the new IAC valve but is critical for installation. If reusing IAC valve, DO NOT push or pull on pintle.
2. Check IAC valve seal for damage. Replace as necessary. Lubricate seal with clean engine oil.
3. Install the IAC valve into the throttle body.
4. Apply Thread Locking Compound (Loctite 262) onto IAC valve retaining screw threads. Tighten IAC valve retaining screw to specification. See «TORQUE SPECIFICATIONS»(ref-153402-S01137901832003040400000) .
5. Connect IAC valve harness connector.
6. Install the air cleaner outlet resonator.
7. Connect the negative battery cable. Tighten to specification. See «TORQUE SPECIFICATIONS»(ref-153402-S15109679952003040400000) .
8. Reset the IAC valve pintle using the following procedure: Turn ignition switch to RUN position for 2 seconds. Turn ignition switch to OFF position for 10 seconds. Turn ignition switch to RUN position. Check for fuel leaks.

Inspection

Spark Plug Usage

1. Ensure that the correct spark plug is installed. An incorrect spark plug causes driveability conditions. See «SPARK PLUGS»(ref-151533-S26331351332002123100000) under IGNITION SYSTEMS in SERVICE & ADJUSTMENT SPECIFICATIONS - 2.2L CAVALIER & SUNFIRE article for the correct spark plug.
2. Ensure that the spark plug has the correct heat range. An incorrect heat range causes spark plug fouling (colder plug), pre-ignition, causing spark plug and/or engine damage (hotter plug).

Inspection

1. Check the terminal post for damage. Check for a bent or broken terminal post. (Scheme 1) Check for a loose terminal post by twisting and pulling the post. The terminal post should NOT move.
2. Check the insulator for flashover or carbon tracking, soot. This is caused by the electrical charge traveling across the insulator between the terminal post and ground. Check for the spark plug boot for damage. Check the spark plug recess area of the cylinder head for moisture, such as oil, coolant, or water. A spark plug boot that is saturated causes arcing to ground.
3. Check the insulator for cracks. All or part of the electrical charge may arc through the crack instead of the electrodes.
4. Check for evidence of improper arcing. Measure the gap between the center electrode and the side electrode terminals. Spark plug gap should be 0.045" (1.14 mm). An excessively wide electrode gap can prevent correct spark plug operation. Check for the correct spark plug torque. See «TORQUE SPECIFICATIONS»(ref-153402-S15109679952003040400000). Insufficient torque can prevent correct spark plug operation. An over torqued spark plug, causes the insulator to crack. Check for signs of tracking that occurred near the insulator tip instead of the center electrode. Check for a broken or worn side electrode. Check for a broken, worn, or loose center electrode by shaking the spark plug. A rattling sound indicates internal damage. A loose center electrode reduces the spark intensity. Check for bridged electrodes. Deposits on the electrodes reduce or eliminates the gap. Check for worn or missing platinum pads on the electrodes. If equipped. Check for excessive fouling.
5. Check the spark plug recess area of the cylinder head for debris. Dirty or damaged threads can cause the spark plug not to seat correctly during installation.

Scheme 1

Visual Inspection

1. Normal operation - Brown to Grayish-Tan with small amounts of White powdery deposits are normal combustion by-products from fuels with additives.
2. Carbon Fouled - Dry, fluffy Black carbon, or soot caused by rich fuel mixtures, leaking fuel injectors, excessive fuel pressure, restricted air filter element or incorrect combustion. Reduced ignition system voltage output, weak coils, worn ignition wires or incorrect spark plug gap. Excessive idling or slow speeds under light loads can keep spark plug temperatures so low that normal combustion deposits may not burn off.
3. Deposit Fouling - Oil, coolant, or additives that include substances such as silicone, very white coating, reduces the spark intensity. Most powdery deposits will not effect spark intensity unless they form into a glazing over the electrode.

1. Gap the spark plug to 0.045" (1.14 mm), using round wire type spark plug gap gauge.
2. Install the spark plugs using appropriate spark plug socket. Tighten the spark plugs to specification. See «TORQUE SPECIFICATIONS»(ref-153402-S15109679952003040400000) .
3. Install the ignition coil housing. See «IGNITION COIL HOUSING»(ref-153402-S39801531862003040400000) .

The Evaporative Emission (EVAP) charcoal canister is located under the vehicle. (Scheme 2)

1. Raise and support vehicle.
2. Disconnect the hoses from the Evaporative Emissions (EVAP) canister.
3. Remove the attaching bolt from the EVAP canister retainer. (Scheme 3)
4. Remove the EVAP canister and the retainer. (Scheme 4)
5. Remove the EVAP canister retainer from the canister. (Scheme 5)

Scheme 2

Scheme 3

Scheme 4

Scheme 5

1. Snap the EVAP canister retainer onto the EVAP canister. (Scheme 5)
2. Install the end of the EVAP canister into the tab on the body. (Scheme 4)
3. Install the attaching bolt to the EVAP canister retainer. (Scheme 3) Tighten bolt to specification. See «TORQUE SPECIFICATIONS»(ref-153402-S15109679952003040400000).
4. Reconnect the hoses to the EVAP canister. (Scheme 2)
5. Lower the vehicle.

Inspection Procedure

Note. Proceed with the following procedure ONLY if referenced by an EVAP diagnostic or repair procedure.

1. Turn ignition switch to OFF position.
2. Remove the EVAP canister purge valve. Refer to Evaporative Emission (EVAP) Canister Purge Valve Replacement.
3. Lightly tap the EVAP canister purge valve on a hard surface.
4. Check for carbon particles exiting either of the vacuum ports. If no carbon particles were detected, but a blockage was detected during a diagnostic procedure, install the original EVAP canister purge valve. Continue with the cleaning procedure. If carbon particles are found during the inspection procedure, continue with the cleaning procedure. If a diagnostic procedure directed you to replace the EVAP canister purge valve and no carbon particles were detected, replace the EVAP canister purge valve. Return to the published service procedure.