C220 cdi not firing after high pressure fuel pump swap

[Jaz1991]

Hi there, just swapper over the high pressure fuel pump on my c220 cdi, with a genuine replacement Bosch spare. The part that came out was a cn2 and its replacement a cn3 . The car is refusing to start, I can see air bubbles rising Ito the small pump and air in the lines back to the filter. I did not fill the pump as there was no obvious filling point, only by submersing the whole pump can it be filled I guess and I haven't done that. Any advice would be greatly appreciated as I have been told its self bleeding but haven't had any joy

 

[Cole@MBS]

They are self bleed but take a lot of cranking, sometimes to the point of flatting the battery, I mean cranking without stopping!!!!!

Welcome to the forums.

 

[Jaz1991]

Hi mate we have already cranked it until the battery flattened and have since recharged it to start another round of cranking. It's still not firing

 

[jj1975]

Hi
If you see air inside of fuel lines it means fuel dont reach the pump , the fuel tank should be full will be easy for the fuel to come up maybe this can help

 

[Cole@MBS]

Have you got the pipes the right way round into the high pressure pump???

 

[Jaz1991]

Hi mate, is there a diagram? I put it back the same way it came off. But a diagram would be helpful

 

[Cole@MBS]

The one line with the black plastic outer goes to the engine side of the pump, the plain clear pipe to the front........

 

[Jaz1991]

Hi there , the car fired up yesterday, but there's still an issue with the fuel lines , there is air passing through from as early on as the filter outlet causing poor starts and sometimes no starts. There is also a slight hissing noise coming from the device behind the fuel filter, that supply's diesel into the filter . Thanks for all of the guidance so far

 

[Steve@Avantgarde]

How much fuel is in the tank? Anything less than 1/4 then go and add 20 litres of diesel and see if it goes. Sometimes if you have less than a 1/4 and you open the system, because its a saddle tank using a venturi effect, air is difficult to disperse. The more fuel in the tank especially if the right side of the tank is full which is the supply side to the engine the easier it is to bleed.

I have had this issue myself.

 

[Camel]

Sorry for the thread hi-jack, but I have had my high pressure fuel pump replaced recently. The car is running great, but my local garage think my fuel gauge is now faulty. The history is:

1) Car broke down - high pressure pump replaced
2) Garage test drive car, and it runs out of fuel with 1/8 showing on fuel gauge (or it breaks down with the symptoms of no fuel)
3) Garage put £20 of fuel in tank, it works ok. They say my gauge could be faulty
4) I fill car up, runs sweet. At approx 1/8 of tank, car won't start.
5) Fill the car up, it is running sweet again.

I don't think the fuel gauge is faulty as when I filled it, it took the right amount.

What is the venturi effect? (I did google it, but it looks soooooo interesting.)

Is there something else that could be wrong with my car? I don;t mind filling up when I get to 1/4 full....but I'd rather not have to I guess.

 

[Jonathan Lingham]

Have you got the pipes the right way round into the high pressure pump???

I wonder if I have the same problem? Is there a diagram? I found this on the site, but it isn't quite the same as my W203 220CDI...as you say, two pipes go into that side of the pump. It's possible I've got them the wrong way round. Does the return pipe from the rail go to the engine side or the front?

 

[mersum1es]

front connector goes to rail, near to engine goes to aux pump