The exhaust gas recirculation valve, or EGR Valve for short, recirculates finely metered quantities of exhaust gas to the engine intake system for increased engine efficiency, reduced fuel consumption and lower NOx emissions.
Digital EGR valves feature a solenoid or stepper motor and, in most cases, a feedback sensor. These valves receive a pulse width modulated signal from the ECU, to regulate exhaust gas flow.
The single biggest cause of failure is the buildup of carbon particles from the exhaust gases along the EGR and intake system passages. Over time this will clog tubes, exhaust gas channels and eventually the valve's plunger mechanism, causing it to either stick open or close. Failures can also be caused by a rupture or leak in the4 valve diaphragm.
The EGR valve works most efficiently at 2600 RPM (under load). When the engine idles for a long period of time (1700 RPM) the "sludge" can't burn off the EGR valve. For best results, don't idle the engine, rather shut it down for long periods. Idling while you fill the pot and then blasting for another hour allows the "sludge" to burn off. Idling while talking to your customer for 45 minutes, then turning the machine off to go home will not allows the "sludge" to burn off.
When an EGR valve is replaced, the engine must be "synced" with the new valve or it will not last as long. This must be done at a qualified facility.
*Not all United Rentals have the proper equipment/techs. Please call to verify first.*