C220 cdi estate 2003 wont start

[Greensquare]

Hi All
I have an issue which is driving me crazy!!, My car started getting hard to start and i had to crank it for longer and longer, it was also smoking quite badly when throttle was applied (dark grey smoke). It now won't start at all, I noticed no fuel was going from the fuel filter along the clear low pressure line to the high pressure fuel pump. After spending many days searching the forums for possible solutions here is what i have done so far............. Had the injectors checked they are ok, changed all the low pressure fuel lines and o rings for new ones, fitted a reconditioned high pressure fuel pump, the one above it is working ok, filled the tank with fuel as my car does not have an electric pump in the tank, changed the fuel filter, checked there is no blockage on the fuel line from the tank by pumping fuel out of the filter feed hose. Having tried all of this and some good advice was given on here it still refuses to start, no fuel leaves the filter when turning the car over, i even by-passed the filter and still nothing. I have tried to bleed the system manually and bubbles appear in the feed pipe from the filter going back into he filter.
Does anyone have any ideas before i tow it to a secluded spot and happily set fire to the ****** thing!!!! it would be a shame as it has served me well for 3 years, its always serviced every 10000 miles and goes through the mot each year without a problem and has covered 135000 miles.
Please Help1
Dan

 

[mersum1es]

Air bubble - so its air in system and no enough rail pressure. Live data would tell 100%.

Has this model metal fuel filter or plastic housing? Sometimes there has been a crack in housing. Did you change all fuel lines (to/from filer, lp pump, etc.), they brittle too when aged.

 

[Greensquare]

Metal fuel filter is new and all the lines are brand new

 

[Blobcat]

Replace the run back tubes, if you haven’t done so already

 

[Greensquare]

Thanks for the reply, all rubber and plastic fuel pipes in the engine bay coming from and going to the metal fuel pipes by the bulk head are new.

 

[mioba]

Did you prime the fuel lines with a hand pump. May be self priming mind!

 

[supernoodle]

Did it just stop running before you tried to fix the poor starting or after you started changing bits?

So that's the Om611 with the mechanical pre supply pump? The clear pipe connects the outlet to the HP inlet. You said the pump above is working, I assume you mean this LP pump. How do you know?
Even if the fuel inlet valve was closed, some fuel should flow through the HP pump through the zero delivery throttle to keep the pump lubricated. So if nothing is coming out, the LP pump is not delivering. You should be able to break into HP inlet to really confirm.

By the way HP pumps don't like running with no fuel, even just cranking.

---

 

[Greensquare]

Hi, yes its stopped starting before I started changing bits, I checked the LP pump by injecting fuel via the fuel filter feed while cranking the engine over, I seem to get fuel to the entire fuel system but when its all back together how it should be it wont draw fuel from the tank, i even fitted a electric oil change pump and sucked fuel from the tank using the fuel filter feed pipe and there is no blockage there either. I will leave it a couple of days as its new year and recheck all the fittings and o rings again.
I will post on here to let you know if I have any success in getting it started, I was a mechanic many years ago so i know my way around an engine, but with garage prices these days its not viable to take it there as the bill will most likely be more than the market value of the car!

 

[M80]

A simple check of the lift pump is to remove the fuel pipe into the filter and feed that into a container.
Each time the ignition is cycled you should get a v significant flow for approx 15 seconds. Until the ECU realises there is no build up of pressure.

 

[mersum1es]

Aux pump failures are pretty rare, air problems are very common. As above, its easy to unconnect hose from aux to hp pump, put a friend to turn start and yourself feed the fuel into bucket. Again - if live data would have been read, we should know is it fuel problems or something else. Also, a test for relief valve could be done. BTW there is one o-ring on relief valve body which rarely could be broken.

Edit: good point below - when I said turn start, I mean crank engine

 

[supernoodle]

A simple check of the lift pump is to remove the fuel pipe into the filter and feed that into a container.
Each time the ignition is cycled you should get a v significant flow for approx 15 seconds. Until the ECU realises there is no build up of pressure.

OP says there is no in electric pre supply. Those first generation common rail systems on OM611 used a separate mechanical low pressure fuel pump. I guess there's a good reason why it wasn't there on the OM646.

You can see the pump here, but note this guy gets the LP and HP around the wrong way.

Greensquare, your check of the LP was with a positive head of fuel. When it's connected it's got a lot more work to do. The fact you've checked you can pull fuel from the tank suggests that bit is OK. So either the LP isn't up to the job or one of the connections between LP and filter is still sucking in air.