Vito 2012 idle poor

[Bennys]

ok I had an issue with mercedes vito diesel 2012 ,the idle goes daft and cuts out at times ,so plugged van in & came up with low fuel pressure , i went ahead and replaced 3 items no1 the complete fuel rail with both sensors no2 fuel filter no3 a short fuel pipe feed to fuel filter in the centre of it gets crimped by a bracket and closes the hose , now once these had been done I then couldn't get it running again, with some help a mate told us to replace injectors this we did & got it running again ,the van runs good but I still have this issue with the idle speed, I need help people , I have connected reader and no faults in engine ,Now what I have discovered if I start the van and don't touch the rev pedal it ticks over perfect all day long but if i press the pedal and rev up the idle goes daft again ? I can then switch off van and restart without touching pedal and it will tick over perfect again , i do suspect the throttle body however its now getting to be costly and making me look stupid , I have looked around throttle body for any airleaks and used brake cleaner to see if engine picked up ,nothing happen , any advise please

 

[SprinterBR906]

Hi

Assuming you have a 4-cylinder OM 651 engine, the reason why you couldn’t re-start the engine after replacing the fuel rail would most likely have been due to air in the system.

When the high-pressure fuel system is opened, it must be sealed. Otherwise air can get into the system and it become very difficult to start without Mercedes-Benz diagnostic equipment.

Going off of your description, it sounds like the quantity control valve is the problem. This is located on the high-pressure fuel pump and can be replaced separately.

You won’t be able to visibly see it until you’ve removed several components.

After first starting the engine, fuel pressure is controlled by the pressure regulator valve. As soon as the engine rpm is increased, fuel control is switched over to the quantity control valve. This is when your symptoms start.

With MB diagnostic equipment, this can be seen on live data. As soon as the quantity control valve takes over, it’s current consumption becomes erratic.

Let me know if you need any further help.