651 C220 cdi Pressure regulating valve

[LennyM]

My 2010 C220 cdi with 651 engine makes siphoning gurgling sound when ignition is switch on, but also when ignition is switch off there is a suction pulsating sound with a high pitch beep or whine.
Disconnecting the supply from the tank, at the filter, it flows strongly when the ignition is switch on. Disconnecting at the filter, the feeder to rail, with the ignition on, the flow is just as strong. Connecting the feeder to the rail, the suction and gurgling sound appears and the vehicle struggles to start. it goes into limp-mode and smokes like a locomotive.

I suspect the Pressure Control Valve on the rail; actually hopping its not the High Pressure Fuel Pump nor the Quantity Control Valve. Any insight please.

 

[alexanderfoti]

I have never replaced a pressure control valve on the rail.
Quantity control valve on the pump I have done dozens.

 

[mersum1es]

injector stuck open?

 

[alexanderfoti]

Yes good point, plumes of smoke are not usually the symptoms of a quantity control valve fault.

Common symptoms are rail presure regulation all over the place compared with setpoint. Logging the rail pressure shows overshoot/undershoot over and over.

Engine surges at low throttle output and idle, hunting up and down.

 

[LennyM]

Yes good point, plumes of smoke are not usually the symptoms of a quantity control valve fault.

Common symptoms are rail presure regulation all over the place compared with setpoint. Logging the rail pressure shows overshoot/undershoot over and over.

Engine surges at low throttle output and idle, hunting up and down.

Thank you for the responses.

Tried to work on the car today, it would not even start. Had a friend's diagnostic machine on it. Readings found were as per the attached.
Would appreciate some exact technical data on what the listed set values should be for each.

The fault code in the attachment, I have no idea where to start tracing an open circuit and hoping to get some guidance as to what the cause of it could be.

Appreciate the assistance.

 

[mersum1es]

well you has no pressure on rail and no sync on cam/crank sensor... both preventing engine to start...

BUT, when that fault code triggered? Before even attempt to start?

 

[LennyM]

well you has no pressure on rail and no sync on cam/crank sensor... both preventing engine to start...

BUT, when that fault code triggered? Before even attempt to start?

 

[LennyM]

Greetings mersum1es.
I got so discouraged I locked up the car up until today. To answer your question:

BUT, when that fault code triggered? Before even attempt to start?
I cannot say for certain. I suspect after attempting to start.

Was advised to open injectors one by one and crank the engine to see if flow is foamy. clear flow on all four (4).

Can someone perhaps assist with the values range for the Y74 and Y94 units?

I also still confused with what the cause can be for error coded P254100 . Someone perhaps compiled a list with possible causes?

 

[mersum1es]

SDS is giving values usually by PWM %...

Your battery voltage is also very low...