C class W204 2008 ESP Malfunction fault !

[dave11674]

Hi guys

My w204 keeys popping this fault up usually once a day

Diagnostics has 2 fault codes in the ecu
Fuel pressure exceeded
Fuel pressure too low

Strange to have both !

So after a bit of digging about me and a friend changed the fpr circled at the top of the rail.
The car was warm when we did this and ran ok after starting
16 hours later i started the car and the engine was shuddering and rocking side to side
Revving wasnt stable either
After driving it and it getting warm the shuddering went away but i was still getting the ESP fault up and engine in limp mode
Cycling the ignition as im rolling gets rid of the esp fault and limp
Engine management light stays on for 4 cycles of the ignition.
But randomly the fault returns

Pics above show fault codes

Anyone had any luck fixing this problem ?

I have star diagnostics to try tests out with

Thanks

Dave

 

[Tuercas viejas]

I can explain this apparent "phnommimmmnanm"!
You have poor fuel flow before or at the injectors!
First things first!
What is the condition and make of the fuel filter "gen you wine" MB or aftermarket?
What is the fuel delivery pressure at the filter or HP pump, A must know!.

Now take into account that the injectors are Bosch "ball and seat" types universally in tech circles known for wear erosion inside the guts of the injector over yes the ball and seat pressure control.
The flow into the fuel rail is set by the quantity control valve, a cotton reel unit like valve mounted on the front of the HP pump.
So in service operation high rates of internal leakage through the injector and out into the leak off rail is fine controlled by the rail sensor and pressure control.
Under high flow rates the quantity control valve struggles to keep up with the fuel flow & pressure so all of the sensors exceed their settings throwing a confusing code about excessive pressure--which it had milliseconds before it fell on its face and caused a stall or limp because it couldn't meet the rate of leakage through the injectors.
So if you have lift pump supply pressure in excess of 65/70 psi 4,5b to 4,8 bar and a good flowing fuel filter, then suspect the injectors.
Remove them, record their cylinder position, and have an official Bosch FIE centre test them on their very sophisticated tester. I bet you will get at least one leaking internally like a stuck pig!
Regards Tuercas Viejas

 

[Blue30]

That’s interesting about the leak off.

I get the same thing sometimes with those codes, once every month or two, and it’s always when cruising say 50mph for a fair while then put my foot down suddenly, does that sound like the leak off thing?

 

[Auto-mobile]

Replace the fuel filter if it hasn't already had a decent one, or replace the fuel pressure sensor bolted to the front of the high pressure pump (2xt20 screws)

 

[Dimitry]

Im driving a 2008 Mercedes Benz C220 cdi w204 and when i accelerate the car goes to limp mode ..i have services all my injectors cause the fault said injector no4 has reach its limit but the car still goes in to limp mode ..can someone help me

 

[Blue30]

That’s interesting about the leak off.

I get the same thing sometimes with those codes, once every month or two, and it’s always when cruising say 50mph for a fair while then put my foot down suddenly, does that sound like the leak off thing?

Same, usually cruising at 50 ish for a long time (M6 roadworks lol) then tip the throttle in and you feel the torque just barely start to build after a slight delay and then boom ESP error.

I used an OBD2 reader to monitor fuel rail pressure, sadly haven’t managed to capture the fault occurring yet but the pressure does seem to lag sometimes then ping straight up with a little overshoot, accompanied by a harsh rattle from the engine, in a way that feels like the fault is trying to occur.

I think I’m going to throw a fuel quantity valve on it when I get round to it they seem to be about 100 quid for MB branded or 60 for Delphi branded.