![]() ![]() The tech connected the OBDII scanner and we got an all clear. OK - this is when I drove to the smog station for re-check. Accelerate the vehicle to 55 MPH (88 km/h) and maintain the speed for at least 3 minutes. Accelerate the vehicle to 35 MPH (55 km/h) and maintain the speed for 20 seconds. This is tough to do with stoplights and traffic, so I only drove like this for about 5 minutes.Ĥ. Performance Gain: Cleaner running engine. ![]() Parts Required: Secondary air pump, air valve and gasket, hose clamps if needed. Quickly depress the accelerator pedal for a moment, and then drive the vehicle at a speed of 53 to 60 MPH (86 to 96 km/h) for at least 9 minutes. Tools: Set of sockets 10mm, flathead screwdriver, plastic gasket scraper, hose clamp pliers, DVOM, test light, fused jumper wires. Didn't do this exactly - had to pull the car out of the driveway first and onto a main street to complete this step.ģ. Accelerate the vehicle to 55 MPH (88 km/h), then quickly release the accelerator pedal completely and keep it released for at least 10 seconds. Allow the engine to idle until the engine coolant temperature gauge needle points between the C and H (normal operating temperature). I started it and let it idle until it was at full operating temp (Coolant 172F) and did the following:ġ. To begin the drive cycle, the car sat overnight in the garage. The secondary air shut-off valve, on the other hand, ensures that the secondary air is only supplied to the exhaust gas manifold during the cold start phase.I ran a single drive cycle on the car, then took it in and it passed no problem. The secondary air non-return valve, for example, stops exhaust gas, condensation or pressure peaks in the exhaust tract (caused by misfiring, for example) causing damage to the secondary air pump. The secondary air valves are installed between the secondary air pump and the exhaust gas manifold. For monitoring by on-board diagnostics (OBD), electric secondary air valves can be fitted with a pressure sensor. Thanks to higher actuating forces, they are more resistant to sticking caused by soot or dirt. be equipped with an integrated pressure sensor for on-board diagnosis (OBD) monitoring. They have shorter opening and closing times than pneumatically controlled valves. All vehicles with spark-ignition engine and secondary-air system. Electric secondary air valves are a very recent development. In later generation secondary air valves, the shut-off and non-return functions are combined in a "shut-off non-return valve". If the system isnt working/functioning properly it does not pass the monitor. ![]() The diagnostic software shows the O2 sensor voltage and determines if enough air was blown into the system. Secondary air valves are actuated in various ways – either by means of negative pressure controlled by an electric changeover valve or by opening due to the pressure generated by the secondary air pump. This includes warming the car up to a certain temperature, then activates the sap pump to blow air into the exhaust manifolds. The secondary air shut-off valve, on the other hand, ensures that the secondary air is only supplied to the exhaust gas manifold during the cold start phase.The secondary air non-return valve, for example, stops exhaust gas, condensation or pressure peaks in the exhaust tract (caused by misfiring, for example) causing damage to the secondary air pump.If the air is drawn not from the intake area but directly from the engine compartment, a separate air filter is built into the secondary air pump. The secondary air pump must draw in ambient air and inject it into the exhaust gas manifold downstream of the exhaust valves. The secondary air system comprises the secondary air pump and the secondary air valves. The heat generated as a result of this process also heats the catalytic converter and reduces the time taken for the oxygen sensor emissions control to commence operation. This causes post-oxidation ("post-combustion") of the harmful substances, creating harmless carbon dioxide and water. To avoid this and reduce harmful substances during cold starting, ambient air containing high levels of oxygen ("secondary air") is injected into the exhaust gas manifold directly downstream of the exhaust valves using the secondary air system. Since the oxygen sensor emissions control and the catalytic converter have not yet reached their operating temperature at the time of this phase, these harmful exhaust gas components can escape into the environment if not re-treated. As a result, high quantities of carbon monoxide and unburned hydrocarbons are produced during cold starting. This means that the fuel/air mixture contains excess fuel. A petrol engine needs a "rich mixture" for reliable cold starting. In petrol engine vehicles, secondary air injection is a proven method of reducing harmful substance emissions during cold starting. ![]()
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