Filed Under (Chevrolet) by admin on 16-09-2010
1. Remove the idle air control (IAC) valve connector. 2. Remove the IAC valve attaching screws (1). 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. 3. Remove the IAC valve assembly (2). ^ Clean the IAC valve O-ring sealing surface, the pintle valve seat, and the air passage. ^ The IAC valve may be cleaned. Use a shop towel or parts cleaning brush to remove any heavy deposits. ^ Any shiny spots on the pintle or seat are normal and do not indicate misalignment or a bent pintle shaft. ^ If the air passage have heavy deposits, remove the throttle body for a complete cleaning. ^ Inspect the IAC valve O-ring for cuts, cracks, or distortion. Replace the O-rings if necessary. ^ When installing a new IAC valve, be sure to replace the valve with an identical part. The IAC valve pintle shape and diameter are designed for a specific application. MEASUREMENT PROCEDURE This procedure is only for installing a new IAC valve. IMPORTANT: If installing a new IAC valve, replace the IAC valve with an identical part. The IAC valve pintle shape and diameter are designed for the specific application. Measure the distance between tip of the IAC valve pintle and the mounting flange. If the distance is more than 28 mm (1.1 in), 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. INSTALLATION PROCEDURE
Filed Under (Oldsmobile) by admin on 10-04-2011
Refer to Engine Controls Schematics MAF, Secondary Air Injection Pump Bypass Solenoid, IAC and Secondary AIR Pump . Circuit Description The AIR pump is used on this vehicle to lower tail pipe emissions on start-up. The powertrain control module (PCM) grounds the AIR pump relay control circuit, which energizes the AIR pump. The PCM also grounds the AIR solenoid valve control circuit, which energizes the AIR solenoid valve. The AIR solenoid valve opens allowing manifold vacuum to open the AIR control valves. The PCM enables both control circuits when AIR system operation is desired. When the AIR system is active, the AIR pump forces fresh air into the exhaust stream in order to accelerate catalyst operation. The AIR control valves replace the conventional check valves. When the AIR system is inactive, the AIR control valves prevent air flow in either direction. DTC P0412 applies to the AIR solenoid control circuit. DTC P0418 applies to the AIR pump relay control circuit. DTC P0410 sets if an air flow problem is detected. The PCM will run two tests using the heated oxygen sensor (HO2S) voltage to diagnose the AIR system. Both tests have two parts. The passive test is performed during regular AIR pump operation. The passive test consists of the following: Passive Test Part 1 When the AIR system is enabled, the PCM monitors the HO2S voltage. If the HO2S voltage goes below a threshold, the PCM interprets this as an indication that the AIR system is operational. Passive Test Part 2 When the AIR system is disabled, the PCM monitors the HO2S voltage. The HO2S voltage should increase above a threshold and switch normally. If both of these tests indicate a pass, no further action is taken. If one of the above tests failed or is inconclusive, the diagnostic will proceed to test two. The active test is performed specifically for diagnostic purposes. Test two consists of the following: Active Test Part 1 During this test the PCM turns the AIR system on during closed loop operation. When the AIR system is activated, the PCM monitors the HO2S voltage. If the AIR system is operating properly, the HO2S voltage should go below a predetermined threshold. Active Test Part 2 The PCM turns the AIR system off. The HO2S voltage should return to above a rich threshold.
Filed Under (Honda) by admin on 21-12-2010
NOTE: If DTC P1519 is stored at same time as DTC P0505, troubleshoot DTC P1519 first, then recheck for DTC P0505. 1. Start the engine. Hold the engine at 3,000 rpm with no load (in Park or neutral) until the radiator fan comes on. 2. Check the engine speed at idle with no-load conditions: headlights, blower fan, rear window defogger, radiator fan, and air conditioner off. Is the engine running at 730+/-50 rpm? YES – Intermittent failure, system is OK at this time.? NO – If the idle speed is less than 680 rpm, go to step 3; if it’s 780 rpm or higher, go to step 4. 3. Disconnect the idle air control (IAC) valve 3P connector. Does the engine speed increase or fluctuate? YES – Adjust the idle speed. If the idle will not adjust properly, clean the passage in the throttle body, and then adjust the idle.? NO – Replace the IAC valve.? 4. Turn the ignition switch OFF. 5. Remove the intake air duct from the throttle body. 6. Start the engine and let it idle. 7. Put your finger on the lower port (A) in the throttle body. Does the engine speed drop below 780 rpm? YES – Adjust the idle speed. If the idle will not adjust properly, replace the IAC valve, and then adjust the idle.? NO – With the throttle valve completely closed, check for vacuum leaks, and repair as necessary.?
Filed Under (Ford) by admin on 08-04-2011
Removal NOTE: 5.0L shown, 4.0L SOHC and 4.0L (push rod) similar. 1. Disconnect the idle air control (IAC) valve electrical connector. 2. Remove the IAC valve. 1. Remove the two bolts. 2. Remove the IAC valve. Discard the gasket. Installation NOTE: Install a new IAC valve gasket. 1. Install the idle air control (IAC) valve. 1. Position the IAC valve. 2. Install the two bolts. 3. Connect the IAC electrical connector.
Filed Under (Mercury) by admin on 28-03-2011
Idle Air Control (IAC) Valve Removal 1. Disconnect the vacuum line from the exhaust gas recirculation valve. 2. Disconnect the idle air control (IAC) valve electrical connector. 3. Detach the wiring harness from the IAC valve stud. 4. Disconnect the vacuum supply lines from the upper intake manifold. 5. Remove the IAC valve. 6. Remove and discard the IAC valve gasket. Installation 1. NOTE: Install a new IAC valve gasket. To install, reverse the removal procedure.