how to clean a idle air control valve ford fiesta
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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 (GM) by admin on 03-11-2010
Located on the throttle body, the Idle Speed Control (ISC) valve opens the air bypass passage when the solenoid is ON and closes it when the solenoid is “OFF.” The ECM turns the ISC solenoid ON and OFF at a constant cycle of 20 times per second. It controls the bypass air flow by making “ON” time one cycle shorter or longer depending on conditions. In this system, the ECM controls the ISC solenoid valve according to the signals from various sensors and switches to control the bypass air flow which plays the following three roles as required by certain circumstances. IDLE-UP AIR FLOW When head lights & other lights, heater fan, rear defogger (if equipped) or air conditioner (if equipped) are operating, and/or the automatic transmission is in a range other than PARK or NEUTRAL, and/or the vehicle is at high altitudes, higher than 8,200 ft or 2,500 m, the bypass air is supplied to stabilize the engine idle speed. How much air is supplied varies depending on the load. When head lights and other lights are ON, the idle speed rises only a little higher than the normal specified idle speed (920 rpm). AFTER START AIR FLOW When and after the engine is started, the bypass air is supplied to prevent the engine from stopping when the throttle opener is OFF and to improve the engine performance at its start. How much bypass air is supplied varies depending on the engine cooling water temperature and it decreases as time passes when engine is cool. When engine is hot and 15 seconds have passed after engine starts, a given amount of bypass air is supplied until either the idle switch is turned OFF from ON once or engine speed exceeds 1,500 rpm once. DASHPOT AIR FLOW A sudden change in the throttle valve opening (especially when decelerating) causes the air/fuel mixture ratio to change suddenly. To compensate for this condition, the bypass air flow will be increased or decreased depending on condition. By increasing or decreasing the air, the air/fuel mixture ratio is changed gradually and dashpot effect is obtained. The air is increased when throttle is opened and decreased when the throttle is closed.
Filed Under (Ford) by admin on 17-03-2011
NOTE: Hydraulic valve lifters are used; no valve adjustment is required. When valve and/or valve seat is machined, valve clearance is reduced and may cause improper valve operation. Different length push rods are available for correcting clearance. Valve lifter must be collapsed to check valve clearance. 1. With valve cover removed, position piston No. 1 at TDC of compression stroke. Completely collapse cylinder No. 1 intake valve lifter and hold valve lifter collapsed. Using feeler gauge, measure clearance between rocker arm and valve stem. 2. Clearance should be within specification. Refer to COLLAPSED VALVE LIFTER CLEARANCE table. Replace push rod, if necessary, to obtain correct clearance. 3. Position crankshaft as specified. See, in this article, VALVE CLEARANCE CHECKING SEQUENCE table, and check appropriate valves. Replace push rods if clearance is not within specification. 4. If push rod(s) is replaced, ensure corresponding cylinder piston is below TDC. It will be necessary to loosen or remove rocker arm to replace push rod. CAUTION: DO NOT operate or crank engine after installing push rod until valve lifter has leaked down to normal operating position. COLLAPSED VALVE LIFTER CLEARANCE
Filed Under (Ford) by admin on 19-02-2011
WARNING: Always wear safety glasses when repairing an air bag supplemental restraint system (SRS) vehicle and when handling an air bag module. This will reduce the risk of injury in the event of an accidental deployment. WARNING: Carry a live air bag module with the air bag and trim cover pointed away from your body. This will reduce the risk of injury in the event of an accidental deployment. WARNING: Do not set a live air bag module down with the trim cover face down. This will reduce the risk of injury in the event of an accidental deployment. WARNING: After deployment, the air bag surface can contain deposits of sodium hydroxide, a product of the gas generant combustion that is irritating to the skin. Wash your hands with soap and water afterwards. WARNING: Never probe the connectors on the air bag module. Doing so can result in air bag deployment, which can result in personal injury. WARNING: Air bag modules with discolored or damaged trim covers must be installed new, not repainted. WARNING: Vehicle sensor orientation is critical for correct system operation. If a vehicle equipped with an air bag supplemental restraint system (SRS) is involved in a collision, inspect the sensor mounting bracket and wiring pigtail for deformation. Replace and properly position the sensor or any other damaged supplemental restraint system (SRS) components whether or not the air bag is deployed. WARNING: To avoid accidental deployment and possible personal injury, the backup power supply must be depleted before repairing or replacing any front or side air bag supplemental restraint system (SRS) components and before servicing, replacing, adjusting or striking components near the front or side air bag sensors, such as doors, instrument panel, console, door latches, strikers, seats and hood latches. Please refer to the appropriate vehicle shop manual to determine location of the front air bag sensors. The side air bag sensors are located at or near the base of the B-pillar. To deplete the backup power supply energy, disconnect the battery ground cable and wait at least one minute. Be sure to disconnect auxiliary batteries and power supplies (if equipped). NOTE: Repair is made by installing a new part only. If the new part does not correct the condition, install the original part and perform the diagnostic procedure again. 1. Disconnect the battery ground cable (14301) and wait at least one minute. For additional information, refer to Section 414-01. 2. Remove the driver air bag module. For additional information, refer to Module — Driver Air Bag in this section. 3. NOTE: Make sure the wheels (1007) are in the straight-ahead position. Remove the steering wheel (3600). For additional information, refer to Section 211-04. 4. Apply two strips of masking tape across the air bag sliding contact (14A664) to prevent accidental rotation when the air bag sliding contact is removed. 5. Place the steering column in the full down tilt position, then remove the tilt wheel handle and shank (3F609). 6. Remove the lower steering column cover. 1. Remove the two bolts. 2. Position the parking brake release aside. 3. Remove the lower steering column cover.