2003 Mercedes c270 cdi cranks but wont start

[crazy123]

so the car got in a crash , when getting the car home i tried starting it , it turned over just fine but didn't start , later i checked there was no preasure in the fuel lines , the fuel got to the filter but not to the injectors.

 

[whizzy]

Have you checked the fuel pump relay/fuse or to see if the car has a fuel cut off switch?

 

[crazy123]

I will check the relay , but i don't know about to cut off ,where can it be ( sorry about my english im from latvia)

 

[miggit]

If you have a CDi engine there wont be any relays for the fuel pump as they are both mechanical items driven off the front of the engine. I have just had a similar problem, I thought that the low pressure / lift pump was at fault, as there was only air bubbles going to the engine from the fuel filter, so I changed it... still had the same problem, not starting.. then noticed that there was still air in the pipes and the fuel was running back to the tank when I stopped trying to start the engine. It was the 'O' rings on the lift pump connections at fault, I got 2 new 'O' rings from my Mercedes dealer for less money than 1 off of Ebay (be warned Ebay isn't always cheap).

A word to the wise, be very careful with the connectors / clips, as they get very brittle. I have managed to break both clips and have been forced to buy 2 new fuel lines, if I was to do it again, I would try to heat up the clips before touching them.. hot water or hair dryer!

 

[crazy123]

What exactly is the lift pump , can u show me a picture of it?

 

[miggit]

J23.9 is the low pressure / lift pump

The 'O' rings are 198 and 214 Mercedes part number A6019970645
To release the clip you have to push the white collar in to the clip, this makes it let go of the pump. You can then pull the fuel line from the lift pump and replace the O ring. Make sure that the clip is warm, as the plastic get very brittle and be gentle wriggling the clip out of the pump.

To be honest it is easier to remove the pump from the pipes, leaving the pipes in place. To do this you will have to remove the vacuum pump (J17.13 top picture). It is held on with 2 bolts and you do not need to remove the pipe, there was enough slack on mine to rest it on top of the engine out of the way. Then release the fuel lines from the lift pump and ease the clips out, undo the 2 bolts holding the pump on and remove, and you will be left with the pipes in place and able to see the O rings.

 

[crazy123]

i think it can't be the pump because before the crash car ran fine
and after the crash , it wouldent start crancked over fine

 

[miggit]

If you think that the fuel system is OK but the engine will not start, I think that the best thing to do is to get the fault codes read with a scanner. There is a chance that there is a cut off relay that is triggered in the event of a crash, but I'd have thought that the airbags would have gone off too. As far as I'm aware fuel cut off systems are normally found on petrol injection engines, as they have electric fuel pumps and they can continue to feed a fire, without the engine running, after a crash. Diesel is so hard to light so this sort of cut out is not normally used, and in the case of the Mercedes 270 CDI engine, the engine needs to be turning over for the fuel pumps to work.... There are no electric pumps on the 270 CDI.

On that diagram, above, of the fuel pipes it does show a fuel cut off valve, it is not numbered, but it is on the left below the bolt numbered 378. If your engine has this setup then that could be the problem. My engine has a different layout and looks like this

The fuel is fed from the lift pump (top) straight into the high pressure pump (Mercedes star shaped with the arrow on it, below) and has that plastic fitting bolted on to the fuel rail and is 'T' d into the fuel line.

 

[mersum1es]

Shut valve was canceled in late of 2001 models forward.

As above, you need to get the codes, read the fuel pressure during cranking.

I remember reading one case where crash data was triggered even air bags didnt deploy

 

[crazy123]

yes my airbags didn't deploy , i had conected a scaner but it didnt show any codes if i remember coretctly they were transmision and airbag , i will try to chek the fuel preasure while cranking.

 

[pmcgsmurf]

You need to use a proper scanner and read the codes, otherwise you are just guessing and could be there for a long time.

Logic would say that something has either triggered or broke in the crash.

 

[crazy123]

something is probably triggered , because in the crsah nothing in the engine compartment vouldnt break

 

[crazy123]

i think the car has a short somewhere because when i turn the ingnition all the accesories tur on and drain the battery i don't have a chance tu turn it over now , but last sumer i could crank it .

 

[Deleted member 149005]

Fuel cut off switch activated?

 

[crazy123]

do diesels have the cut off?

 

[crazy123]

i still cant find the problem

 

[pmcgsmurf]

i still cant find the problem

What did the Star Diagnostic say?

 

[crazy123]

didn't show any codes

 

[crazy123]

it dosent show any signs of fuel preasure to the injectors .

 

[mersum1es]

it dosent show any signs of fuel preasure to the injectors .

read by diagnostic?

Do you have at least half tank fuel?

You can test aux pump, remove aux pump feed to hp pump (line where 214 number is), ask someone to crank engine. If fuel starts pouring, stick hose back to aux pump delivery connection. Careful, fuel is not coming super fast but will soak some of the engine bay/ use gloves and safety glasses.