What symptom would be present if an EGR valve sticks open?
What symptom would be present if an EGR valve sticks open?
Check engine light: as with most engine management components, a problem with the EGR valve may trigger the check engine light. Engine performance issues: if the valve is stuck open the vehicle’s air-fuel ratio will be disrupted causing engine performance issues such as reduced power, poor acceleration and rough idle.
Is there a sensor on the EGR valve?
A manifold absolute pressure (MAP) sensor is fitted to the intake manifold. The EGR valve and MAP sensor are quite accessible on this particular engine so testing the system was straightforward. After reading the diagnostic fault codes, I used an actuator test on the EGR valve. The valve could be heard moving inside the housing.
What happens when the EGR valve is stuck?
But when the EGR valve is stuck open, the engine will suck in air that is already measured by the MAF sensor, leading to a lean air-fuel mixture and a reduction in fuel consumption. While this might sound like a great symptom, it can damage your engine.
How is the EGR valve on an OBD 2 engine controlled?
If it is not, it can make for hard starting when the engine is cranked. On most OBD II vehicles, the EGR valve is controlled by the powertrain control module. If teh engine has a vacuum-operated EGR valve, the PCM controls a solenoid in the vacuum line to open and close the valve. The PCM may cycle the solenoid on and off to vary the EGR flow rate.
How many solenoids does an EGR valve have?
“Digital” EGR valves have several solenoids (two or three in the case of GM). Each has a different sized valve (small, medium and large). The PCM varies the flow rate by energizing various combinations of the solenoids. The solenoids are normally closed, and open only when the PCM completes the ground to each.
How is the scope connected to the EGR valve?
The lab scope is connected to the EGR valve DC motor and position sensor via a Measure lead TP-C1812B and Back Probe TP-BP85 and set to recorder mode . In recorder mode a streaming measurement is performed, continuously displaying the signals live on screen.
How is the EGR valve DC motor and position measured?
The EGR valve that is measured is equipped with a DC motor to control the valve and an EGR valve position sensor to give feedback to the ECU about the position of the EGR valve. The EGR valve is spring loaded to keep it closed.
How is the potentiometer connected to the EGR valve?
The potentiometer contains a carbon track over which a slider slides that is mechanically connected to the EGR valve. One side of the carbon track is connected to the power supply and the other side to the ground. The sensor signal is produced from the slider that moves over the carbon track which changes the signal voltage.
What should I do if my EGR is not working?
Common EGR problems include: Pinging (spark knock or detonation) because the EGR system is not working, the exhaust port is plugged up with carbon, or the EGR valve has been disabled. The fix here is to inspect the EGR system, remove the EGR valve and check the valve and port for carbon, and remove the carbon from the port if it is plugged.
