99 plate c250 td starting issues.

[Ad777]

Hi all, i wonder if i could get some advice please. I bought this car a couple of weeks ago, it sounded a wee bit rough on start up but then drove perfectly..never having had a merc before i didnt give it too much thought. 3 days ago, it just turned over and didnt start. eventually after cranking it slowly caught, then fine for the rest of the day. It has been the same for the last 2 days, so this is no longer intermittent. i got to a garage today he checked the glow plugs and controller, all fine..he started saying it might be the engine compression or the fuel pump, the engine i am sceptical about as it only had 1 old owner and 100,000 miles. There are no faults showing on the car, but hasnt been scanned yet. I have seen various posts about the plastic piping into filter etc, could this cause these symptoms? is it quit easy to change! The car drives perfectly and starts all day after the initial hassle. Any help and advice would be greatly appreciated, cheers Adam

 

[Doug1234]

Hi , yes the plastic fuel pipes can cause this due to o rings fitted to them but first make sure the fuel tank is at least half full as this car has what are called saddle tanks where fuel is meant to level itself out between each side of the car... it often doesn’t and its normally when the fuel gauge says about a third full the car will not start.
Search saddle tanks on this forum

 

[Ad777]

Hi , yes the plastic fuel pipes can cause this due to o rings fitted to them but first make sure the fuel tank is at least half full as this car has what are called saddle tanks where fuel is meant to level itself out between each side of the car... it often doesn’t and its normally when the fuel gauge says about a third full the car will not start.
Search saddle tanks on this forum

Thanks Doug, the tank is exactly half full, although i parked on quite a steep hill the night before it first happened! is there a step by step 'how to' for changing the plastic pipes and 'o' rings? and do i have to get them from mercedes dealer? appreciated, adam

 

[LostKiwi]

As above.
Air ingress via failing seals on the plastic pipes is common.

If possible try parking overnight with the front facing downhill. If it starts normally it's definitely air leaks.

 

[Ad777]

As above.
Air ingress via failing seals on the plastic pipes is common.

If possible try parking overnight with the front facing downhill. If it starts normally it's definitely air leaks.

Thank you also. Easy to change? need to get from dealership? cheers

 

[LostKiwi]

Never done them (I don't use the devil's fuel )

Apparently not difficult but the pipes get brittle with age and break. May be worth replacing pipes and seals together.

 

[Ad777]

Never done them (I don't use the devil's fuel )

Apparently not difficult but the pipes get brittle with age and break. May be worth replacing pipes and seals together.

thanks again! hopefully someone who has done them might give me some pointers!

 

[Ad777]

So a quick update. yesterday after another hard morning start, was driving and lost boost power, a bit anyway, and heard a whooshing noise when trying to accelerate. Although the tank was sitting at just under a half tank, i filled it full. As soon as i drove off normal driving resumed! When went to start this morning no trouble at all. So this would indicate that when i parked it uphill the fuel had run back maybe ? Am still going to replace pipes and o rings.. how do i fit a non return valve to stop this happening again?

 

[Doug1234]

If you replace the pipes and o rings you will not need a non return valve.
But give a few more morning starts with the full tank as saddle tank syndrome may have been the cause and not the pipes/ o rings.

 

[Ad777]

If you replace the pipes and o rings you will not need a non return valve.
But give a few more morning starts with the full tank as saddle tank syndrome may have been the cause and not the pipes/ o rings.

It seems to be starting ok now..i will just keep it over 3/4 full, and see what happens over the next week or so. Thanks for help and advice.