W164 fuel line O-rings

[mercman149]

Morning,
Is there anyone who can tell me how many O-rings my 2008 diesel ML280 has in it's fuel system and where they are?
It's become quite stubborn to start and I've read that these rings harden over time and allow air into the system.
Battery is good. so are the glow plugs and the relay.
Thanks

 

[mersum1es]

Not o-ring problem. You have OM642 engine, o ring problems are related to OM61X series.

Check injector tank line leaks first.

 

[mercman149]

Not o-ring problem. You have OM642 engine, o ring problems are related to OM61X series.

Check injector tank line leaks first.

Hi,

Thanks for your reply. A definitive answer at last and confirms what I suspected.
I plan to check the line next, although there is no obvious diesel smell about the vehicle.
My local indie suggested the fuel temp sensor could be faulty but didn't expand any unfortunately.

 

[mersum1es]

Hi,

Thanks for your reply. A definitive answer at last and confirms what I suspected.
I plan to check the line next, although there is no obvious diesel smell about the vehicle.
My local indie suggested the fuel temp sensor could be faulty but didn't expand any unfortunately.

Yes, fuel temp sensor may prevent starting totally, but I can't remember reading it cause only long starts. But it is easily chekced via live data.

Have you tried double ingnition cycle, before switching key start position?

 

[mercman149]

Yes, fuel temp sensor may prevent starting totally, but I can't remember reading it cause only long starts. But it is easily chekced via live data.

Have you tried double ingnition cycle, before switching key start position?

Hi,

I'll need to borrow my mates code reader again and get that done.

I have tried the double ignition cycle without success. What I did notice today was that the fuel pump keeps spinning after the ignition is turned on, but I don't hear the 'click' of the fuel pressure switch or whatever it is that makes a noise after the pump has been running for a few seconds. I only heard it after the 4th time I switched on the ignition this morning.

Do you know anything about what makes that 'click'?

 

[mercman149]

Yes, fuel temp sensor may prevent starting totally, but I can't remember reading it cause only long starts. But it is easily chekced via live data.

Have you tried double ingnition cycle, before switching key start position?

No message here.

 

[mersum1es]

I don't know clicking source, but it sounds fuel lines are empty/leaks so that primer pump can produce enough flow only after a time, this prevents rail pressure rising fast anough and thus causing longer crank/start. Injectors leaks ara usually temp related.