C270cdi air in fuel problems

[renrutp76]

For quite a while now, I have been having power problems. Took car to a Mercedes specialist after several EPC shutdowns, but no faults were logged. At the time a cheap fuel filter was fitted, so after reading a few threads, I decided to get a genuine MB filter. After fitting, I noticed that there was quite a lot of air passing in the pipe between the filter and lift pump. I have now replaced the filter o ring, and the rubber hoses from bulk head to pre heater and then to filter, but there is still no improvement. Where else can the air be coming from?

 

[turbopete]

can i ask, what were the 'power' issues (apart from the EPC shutdowns) ie turbo lagging excessively, etc?

re the air, are the fuel hose clips tight? is there a water drain plug in the fuel filter that may be drawing air in?

does the leak off pipe divert back to the filter or the tank on these? i cant quite picture the set-up and its too wet here to look at my car! if the leak off goes to the filter, it could be a perished leak off hose

 

[renrutp76]

Hi Pete.

Power issues included general sluggishness, turbo lag, and occasional spluttering.

I am think the spill return goes straight back to the tank, but am not certain.

 

[turbopete]

was there any smoke on acceleration when the car was sluggish, as other than that, my car has similar symptoms (except the air in fuel)

 

[renrutp76]

Hi Pete, lots of smoke on acceleration. When standling, turbo seems ok, no induction leaks that I can find. EGR has recently been cleaned, but not sure how to test (I will have a go at deleting the EGR once the weather gets better). Biggest problem at the moment is the air. I have had a look at a fuel schematic, and it looks like the leak off pipes connect into the common rail return back to the tank. Is there a filter/gauze in the tank?

 

[turbopete]

sounds VERY similar to my car then. im going to have to investigate when time and weather allow!

 

[renrutp76]

Just to update, air still a problem.

Today I have disconnected the black rubber tube from the bulk head, and run a clear section to the fuel filter. It appears the air is coming from the tank or a split in the solid pipe

Anyone any ideas?

 

[renrutp76]

Found some info on this forum relating to HP pump problems (sticking pilot valve) causing a reduced flow back to the tank (search cdi pump rebuild). New seal kit collected from MB £42 for some "O" rings. Also found no 3 injector seal passing. Busy day ahead......

 

[renrutp76]

quick tip, make sure you replace the fuel lines, as these become very brittle, especially when you have fists of ham :Oops:

 

[mercedes13156]

Don;t neglect the leak off pipes. The cloth wound pipes are very tight onto the tee pieces on top of the injectors. You'll break them if you try to remove the pipes. Best to remove the circlip holding the tee pieces into the top of the injector and pop them out then tuck the whole lot out of the way. Don't forget to stuff some clean kitchen roll into the holes to prevent muck getting in.

 

[renrutp76]

Just to update, this has jumped to another thread.

http://forums.mercedesclub.org.uk/showthread.php?t=129925