Tackling aftermarket challenges – a look at future trends for independent workshops
Installation and Fault finding
- Drain engine coolant, referring to the car maker’s instructions. Locate the EGR Valve and disconnect its connector and water hose. Remove the mounting bolt(s) and nut(s). Then remove the EGR Valve and gasket(s)
- Install the new EGR Valve with new gasket(s) and the original mounting bolt(s) and nut(s). Torque the bolt(s) and nut(s) to the car maker’s specifications. Then connect the EGR Valve connector and water hose
- After the EGR Valve installation is completed, add engine coolant and check for engine coolant leakage, referring to the car maker’s instructions. Then check for exhaust gas leakage.
Recommended Installation Torque Specifications
- Electronically controlled EGR Valves are used in engines with an EFI (Electronic Fuel Injection) System, and cause the engine warning light to switch on when there is a malfunction.
- The most common cause of EGR Valve failure is clogging caused by deposits, causing the valve to stick or preventing it from opening or closing properly.
A faulty EGR Valve carries no danger to life, but may shorten the engine life, increase harmful emissions and cause driveability problems such as:
- Rough idling
- Start-up difficulty
- Poor drivability: Hesitation during acceleration or abnormal knocking
- Increased emissions: Elevated NOx emissions and even elevated hydrocarbon (HC) emissions in the exhaust
There could be other causes of poor operation with electronically controlled EGR Valves. One cause can be a faulty intake air temperature sensor which is located in the MAF Sensor, because it is one of the sensors that enables the ECU to determine the correct amount of EGR flow and adjust EGR Valve for precise control. Therefore, for a correct diagnosis always check the DTC codes for EGR Valve problems and refer to the car maker’s instructions for test procedures.
Cleaning the EGR Valve of carbon deposits might be considered as a temporary solution, but it is not recommended. It is almost impossible to remove clogging completely, potentially allowing harmful contaminants to enter the engine. The right solution is therefore to replace the EGR Valve with a new one that is calibrated to the same specifications as original one.