W202 C250TD fuelling issues

[adile220]

Hi All,

I have a C250TD with intermittent starting issues - after searching theres a great deal out there that makes me think its air in the system being the cause.

However, to describe what happens:

Car starts and drives faultlessly - power is great and economy is as it should be. Car is left off for about 2 hours - starts and drives no problems.

Car is now left overnight on the drive (which is flat). Sometimes it will start with no issues, other times it wont start at all. Have to start it using easy start in the inlet, and some loud tapping noise later on starting, get it running.

Could someone advise on where to start when diagnosing this issue? Experiences of solving the issue would be most appreciated.

Best Regards,

Adil

 

[Dieselman]

Look for air bubbles in the clear pipes under sharp acceleration.

 

[guydewdney]

all the clear pipes are about 50 quid to replace the lot and not a single tool required. the most obvious other is the 'stop solenoid o ring' at about 25p and two torx screws to replace. both novice mechanic jobs, just be clean clean clean - wash the whole area first with gunk / jizer.

 

[adile220]

Hi Guy,

Thank you for your advice - and for the PM also.

After the correct part numbers which I think I've seen on another post, but would appreciate it if someone could clarify what is required.

Best,

adil

 

[guydewdney]

Go to the stealer, vin number in hand (wdb202........) its on the windscreen near the tax disc.

Ask for the stop solenoid o ring

Pay the man

Go home, fit it.

See if that fixes it, if not, come back here.

 

[adile220]

Thanks Guy,

Will update once installed.

Best,

Adil

 

[adile220]

Hi Gents,

Installed the 'O' Ring, and the symptoms still persist - in all honesty the old ring didnt look too shabby (quite dry where it was sat on removal).

One thing I did notice is that the fuel filter looks to be a pattern part - definitely not a Mercedes item.

Could this contribute to the issue?

Further direction would also be appreciated.

Best,

Adil

 

[guydewdney]

Next most likely culprit is the filter seal and the prefilter o ring. Again, easy fixes.

19mm spanner, undo big bolt on top of the filter housing, remove filter. Do this somewhere where mess wont matter ad fuel goe everywhere.

Remove (10mm spanner nut) on top of filter housing holding small metal plate to your left. Pull up egg shaped prefilter. Remove o ring and replace. Examine pre filter and clean if filthy.

If this fails, then its probably the o rings on the pipes. Push whte c clip,'in' and pull pipe off. Depending on money/time, either replace o ring or whole pipe. They get brittle, so they may well break. Pull c clip back out when its installed.

Fuel flows from under pre filter to stop solenoid, then to up to the filter proper, then down again to the pump. Check for bubbles.

 

[91dm]

Have a look at the condition of the rubber pipes that join the tank pipes at the bulkhead to the fuel heater. The rubber had perished and was allowing air in, I tightened the clips and it started every time so replaced the rubber pipe and fitted new clips.

 

[adile220]

Thanks Gents,

Will take the next steps and report back in.

Best,

adil