W163 270 CDI engine won't start

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byyt

New Member
Joined
May 15, 2015
Messages
12
Car
Mercedes ML 270CDI
I just bought a 270 CDI 2002 home and have just tried to start it and it won't fire. All the warning lights come on in position 2.The heating coil light goes out but all the others stay on and the car tries to turn over but won't fire. Any ideas?
 
A common problem seems to be the tank mounted fuel pump, I have had a couple of them go one around the 130,000 mile and the other around the 180,000mile mark, the main pump just won’t pull the fuel up on its own.
 
I just bought a 270 CDI 2002 home and have just tried to start it and it won't fire. All the warning lights come on in position 2.The heating coil light goes out but all the others stay on and the car tries to turn over but won't fire. Any ideas?

It is or it isn't turning over ?

Get a MB Star session booked for it.
 
If it turns over, but doesn't fire the engine - possible fuel pump issue, either tank or HPP at front of engine, also, air bubbles in clear plastic fuel lines - new seals required.
If it doesn't turn over at all - check for broken earth strap from chassis to starter motor.
 
Update

Greenfly were called and they started the engine eventually. They said it was the glow plugs. When warm the car seems to start ok now so I guess I know what needs doing, although the car seems to make what sounds like a grinding noise (I know theres a whoosh sound in some other MLs but this sounds more like grinding). At least I have a glimpse of things to come! Thanks for all your suggestions. I am going to check them all out. It's good to see there is so much knowledge on this site. As a Land Rover owner previous to this, the forums often provide more insight than specialists and main dealers. Thanks again.
 
Update

Greenfly were called and they started the engine eventually. They said it was the glow plugs. When warm the car seems to start ok now so I guess I know what needs doing, although the car seems to make what sounds like a grinding noise (I know theres a whoosh sound in some other MLs but this sounds more like grinding). At least I have a glimpse of things to come! Thanks for all your suggestions. I am going to check them all out. It's good to see there is so much knowledge on this site. As a Land Rover owner previous to this, the forums often provide more insight than specialists and main dealers. Thanks again.

Update. The engine now starts and stalls. Then it starts if you turn the key and hold it for 30s which is not ideal. I am thinking its not the glow plugs and am now thinking maybe you are right about the fuel delivery system. Is there any way of checking?
 
A common problem seems to be the tank mounted fuel pump, I have had a couple of them go one around the 130,000 mile and the other around the 180,000mile mark, the main pump just won’t pull the fuel up on its own.

You sure about that?, my 2002 facelift 270cdi ML doesn't have a fuel pump in the tank, the only fuel pump it has is the mechanical one at the front of the engine, immediately above the HP pump.
ps.... I know for sure as I replaced the tank sender unit some time ago.
 
Update. The engine now starts and stalls. Then it starts if you turn the key and hold it for 30s which is not ideal. I am thinking its not the glow plugs and am now thinking maybe you are right about the fuel delivery system. Is there any way of checking?

Get a MB Star session booked for it.

Otherwise your wasting time and money with guess work.

:)
 
Fuel issue if its cranking for 30seconds and then starting 100%
 
High pressure pump seals perished. Same as what happened to mine. Is it wet around pump ?. Does cabin smell of fuel ?
 
Had a similar thing on my ml270. Not saying it's the same but it was air getting into the fuel lines. Check all your rigid plastic fuel lines they have push fit male ends with securing clips. The clips can become brittle and break off leaving a connection loose letting air in. Also the male plastic fuel line terminating plugs have o rings which harden and flatten with age( a common problem on these) so changing the o rings may cure the problem there are 6 ends I think. O rings are about a quid each from stealers. Not too bad to fit but be careful as the fuel lines at that age get brittle and the plastic breaks. In the end I replaced the fuel line from the fuel filter to the Low pressure pump and the one between the low pressure pump to the high pressure pump , lines were aprox £35 each, but hopefully you can get away with the o rings. The lines under the high pressure pump are pretty fiddly so be patient. If you do replace the fuel lines under the go pump you will need to buy 2 of the pipe retaining brackets ( about £1.50 each) as the old ones will break. That's where my money would be. Good luck
MOZ

See post ' W203 Diesel 2.7 intermittent starting issue (wired)' posted by costabunny on 14-05-2015, also do a search, loads of info on common problem of air in the fuel lines on the 2.7 diesel in the W163, W203 etc.
 

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