Where did Flo come from?
Some where the relief valve is located. After checking the VSV for proper operation and confirming that the air pump is actually pumping air, it is time to dig into the engine to check the valves and clean the air passages, if possible. Removing multiple components on the Porsche 911 gives you access to the forwarding valve or the “Dump” and non-return valve. Porsche uses a vacuum tank to help operate the vacuum in low engine vacuum conditions. It is mounted on the fixture that hangs over the air ducts that we are looking for. Ahhhh! here it is. A very dangerous and very elusive relief valve. I think I'll go crazy.
The larger threaded hole is where the non-return valve is attached to the fasteners, and the smaller silver-coated threaded hole for the air line that feeds the right cylinder head. The check valve will be replaced, even if it still passes the air. More importantly, the store air will be passed through the air passages, trying to open them so that the air can reach the exhaust side of the cylinder heads.
Air line on the right side of the cylinder head
Thus, we derive the paths of passage, collect and test the injection of secondary air. Manual start of the pump, we got an acceptable voltage change in the O2 sensors. After two cycles of the On-Board Diagnostics cycle, check the operation of the secondary injection, how it works correctly. Now everything is in order to return the car to the client with a tie, which we cannot know how clean the aisles are. They are unlikely to improve, but enough air passes at this time to meet the EPA standards, programmed in DME and controlled by OBD II.
How does the Engine Guide know?
Connected port for the injection of secondary air on the Mercedes-Benz M112 V-6
Thus, the air pump does not cope with the task of heating a three-way catalyst. How does DME (Digital Motor Electronics) know any way? Programmed into a computer is a self-test of the air pump. Each time a car starts up DME, at some point in the drive cycle, the air pump is turned on to make sure it is working. How interesting, interesting. Part of the fuel management system is oxygen sensors or newer cars. AF sensors (air / fuel) or oxygen sensors in a wide range are reported to DME. Feeling the amount of oxygen in the exhaust gases, these sensors allow DME to make adjustments to the air in the fuel mixture entering the engine to ensure maximum efficiency under all conditions.
O2 sensors also report DME if air from the air pump reaches the catalyst. If the secondary air injection system is working properly, DME should see a voltage drop in a conventional O2 sensor. On the new A / F sensors, the technician will need to obtain data on fuel trimming to find out if the fuel system is trying to adjust when the air pump is activated artificially. Thus, an air pump inflates the air, but there are some mechanical controls on which air actually falls on the exhaust side of the equation. There is a vacuum switching valve (VSV) and a vacuum “Dump Valve” which, when using vacuum through VSV, allows air to enter the exhaust through a non-return valve that causes the exhaust gases to return through the damaged valve “Dump Valve” that is the pump.
Thus, long and short, DME turns on the air pump, sensors do not notice changes indicating a malfunction or insufficient secondary air flow, and DME turns on the engine control light. Now what? Come in.
In one of them there are tools that fix Check Engine Lights
Therefore, we decided to take the bitter pill. We are dealing with a failure of the injection of secondary air P0411. To understand what this means, we need to understand what the injection of secondary air is and what it should do with proper operation.
Universal Scan Tool
We are mostly familiar with the catalytic converter, which has required the use of unleaded gas since 1975. 3-way catalytic converters destroy hazardous carbon monoxide to harmless carbon dioxide. They also destroy toxic hydrocarbons into carbon dioxide and water, while simultaneously reducing oxides of nitrogen to ordinary nitrogen and oxygen. In order for the cat to do this work, it must be hot, which may take some time. To meet strict emission standards, an air pump was added to heat the Cat faster and reduce harmful emissions faster. Pump air into the exhaust and it gets hotter faster. When the cat reaches 400-600 degrees Fahrenheit, it begins to clear the exhaust.
So that you know if the emission system is working properly, a number of self-diagnosis schemes have been programmed into the engine management system. One of them is self-testing of air injection or secondary air pump. If this self-test fails, the engine warning light will come on and diagnostic trouble code P0411 will be stored in your engine management processor. In this case, the processor is called DME. Not as fun as MMI, but DME serves for that.
