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Stan, Mercedes Technician
Category: Mercedes
Satisfied Customers: 3526
Experience:  Technical support engineer
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Mercedes sprinter(###) ###-#### ***** fuel rail pressure so wont

Customer Question

mercedes sprinter(###) ###-#### ***** fuel rail pressure so wont start. give it a small amount of easy start and it fires striaght up. Also if i disconnect the pressure sensor the fuel pressure goes up and it will start. Fitted 4 new injectors, new pressure sensor. not sure what to do next
Submitted: 2 years ago.
Category: Mercedes
Expert:  Stan replied 2 years ago.
there are 2 valves in the commonrail system which might cause insufficient fuel pressure for startup. One is pressure regulating valve at the rear of the fuel rail, other one is quantity control valve at the high-pressure pump.
Both of them can cause such symptoms. They can be tested via automatic test with Star Diagnosis.
Otherwise most likely the pressure regulating valve is the cause. It is used during startup to acheive the base pressure in the rail, when the injectors start to be activated

Best Regards,