ML 350 2010 no power and hard to start first thing

[Mercedeschris]

i have recently bough this 2010 ML350 CDI. It takes about 30 secs cranking to fire up first thing in morning. It will not rev over 3000rpm and is lacking power. I have the following codes for Y74 and Y94. But it appears the Y74 can’t be changed on its own and a new fuel rail is required? Any pointers greatly appreciated car has done 104k miles.

 

[pcthrillrider2]

fuel rail pressure sensor?

 

[Mercedeschris]

thanks for reply...
On my Star Machine it shows the fuel pressure to be within spec. Altough I've only just bought it so I need to make sure I'm interpreting data correctly.
I'll update with any progress I make. My daughter has the identical ML so I may swop the Y94 QCV. Not sure whether they need setting up when swopped??

 

[mersum1es]

fuel quantity valve failures are pretty common. You can also find separate 2nd hand pressure valves, it can be changed.