2012 ML250 - Help....Fuel System Needs Replacing?

[Mast]

My 2012 ML250 has developed a fault where by it stalls occasionally when cold and idling at a junctions, usually before the ECO system has kicked in.It always re-starts first time. The problem has been happening for about 6 months but is very intermittent, nothing for a few days then 3 times in one journey until the car has wamed up.

The car has been in to the main dealer 4 times, they have tried various things but failed to find the problem. They have just rang to say there are iron-filings in the fuel, this is caused by the some part of the fuel system (pump?) breaking up and must have been due to a mis-fuel (i.e. I’ve put petrol in a diesel engine) and a lack of lubrication. They say this is the cause of the stalling and the Mercedes warranty is obviously therefore invalid.

I know the main dealer won't believe me but I'm 100% sure I haven't mis-fueled and therefore there must be another root cause. The car drives perfectly and I've had no other problems than the stalling.

Could there be another cause of the iron-filings/failure in the fuel system?

Can they just invalidate the warranty or do they have to prove mis-fueling?

I bought the car as an ex-demonstrator 18 months ago from the main dealer, could the mis-fuel have happened that long ago and only now be causing the problems?

One thing that I do wonder is whether it could be caused with contaminated or poor quality Diesel? I usually fill up with standard diesel at the local supermarket rather than a branded filling station.

I'm now waiting for the main dealer to call me back with what needs doing and a cost.....any advice appreciated, I fear a very large bill coming my way.

Thanks.

 

[Boxbrownie]

I am sure they would have to prove you misfuelled, as it is they are speculating and I am not sure speculation is a valid get out clause in the warranty.

Basically they are trying it on.......it could have course been misfuelled during the 18 months before you bought the car, maybe its their fault?

Then again thats just speculation!

 

[television]

I too think that they are trying it on, there is no substance to their claim. They always try it on, as some just say thank you and pay up.

I ask myself why only when cold, but I do not know this engine well enough to say more.

It must be easy enough to clean it all out and replace the filters.

 

[Ratclapcheese]

Diesel not getting through to the engine!

I want to tell you a story! 3 weeks ago my wife came to me saying that the car won't start. The gauge was reading between half and a quarter full. I turned the starter motor with no effect. She was right it sounded dry. I went to a nearby filling station with a Jerry-can and poured £10 of diesel into the tank. The engine started when it had syphoned fuel from the tank through to the engine. I then went to fill it up completely and ran the car locally until the end of the week when she told me the same problem had occurred. This time the gauge was showing just under three quarter full. I went through the same procedure
but I'm filling up with diesel every time I get close to the three-quarter mark in the fuel gauge. Anyone had this happen to them and what the cause is? I have a 2001 C220 Elegant and it's in very good condition inside and out.

 

[Alex Crow]

I want to tell you a story! 3 weeks ago my wife came to me saying that the car won't start. The gauge was reading between half and a quarter full. I turned the starter motor with no effect. She was right it sounded dry. I went to a nearby filling station with a Jerry-can and poured £10 of diesel into the tank. The engine started when it had syphoned fuel from the tank through to the engine. I then went to fill it up completely and ran the car locally until the end of the week when she told me the same problem had occurred. This time the gauge was showing just under three quarter full. I went through the same procedure
but I'm filling up with diesel every time I get close to the three-quarter mark in the fuel gauge. Anyone had this happen to them and what the cause is? I have a 2001 C220 Elegant and it's in very good condition inside and out.

Hi,

It is bad form to tag onto the end of another thread, of no relevance - I suggest you start a new thread, if looking for help and advice.
(the fault may well be the return flow from the main pressure pump though)

 

[Alex Crow]

My 2012 ML250 has developed a fault where by it stalls occasionally when cold and idling at a junctions, usually before the ECO system has kicked in.It always re-starts first time. The problem has been happening for about 6 months but is very intermittent, nothing for a few days then 3 times in one journey until the car has wamed up.

The car has been in to the main dealer 4 times, they have tried various things but failed to find the problem. They have just rang to say there are iron-filings in the fuel, this is caused by the some part of the fuel system (pump?) breaking up and must have been due to a mis-fuel (i.e. I’ve put petrol in a diesel engine) and a lack of lubrication. They say this is the cause of the stalling and the Mercedes warranty is obviously therefore invalid.

I know the main dealer won't believe me but I'm 100% sure I haven't mis-fueled and therefore there must be another root cause. The car drives perfectly and I've had no other problems than the stalling.

Could there be another cause of the iron-filings/failure in the fuel system?

Can they just invalidate the warranty or do they have to prove mis-fueling?

I bought the car as an ex-demonstrator 18 months ago from the main dealer, could the mis-fuel have happened that long ago and only now be causing the problems?

One thing that I do wonder is whether it could be caused with contaminated or poor quality Diesel? I usually fill up with standard diesel at the local supermarket rather than a branded filling station.

I'm now waiting for the main dealer to call me back with what needs doing and a cost.....any advice appreciated, I fear a very large bill coming my way.

Thanks.

I suggest you move quickly to secure evidence - if they claim filings in the fuel system automatically mean you need to pay for a repair costing thousands.
They should be happy to show you the dismantled parts with the vehicle, you can take a friend and a camera I would think. Maybe a knowledgeable friend.
My worry here is that the dealer network has experience of arguing this point, where you do not. If it were to go to court, they could offer lots of circumstantial evidence to make their point - but it seems that is all they have, without a fuel sample test to prove it (sadly all to easy for #someone# to add a little petrol after the fact - so beware!)
Indeed, I might be tempted to secure a fuel sample myself, ASAP, if I were you - if a sample shows no petrol component, they have no evidence.

 

[Mast]

Good News

An update in case it is of interest.....the problem is finally sorted!

The problem got progressively worse, stalling regularly and sometimes "jolting", with a sharp drop in revs, when the engine was idling.

The main dealer had the car in a number of times and tried different things (including draining/flushing out the diesel and replacing the fuel filter) but it made no difference. The most likely reason suggested all along was damage caused by me mis-fuelling but I stuck to my guns that that wasn't the case.

This week they had the car again and noticed a slight variation in fuel pressure, it turns out I had a faulty high pressure fuel pump. They've replaced it under warranty and the car drives like a dream.

To be fair to the main dealer they've been good all along,despite making me doubt my own mind with the mis-fuelling, and have stuck at it. I've even ended up with a letter of apology for the inconvenience and £100 towards a night out as compensation!

 

[EmilysDad]

An update in case it is of interest.....the problem is finally sorted!.....
..... The most likely reason suggested all along was damage caused by me mis-fuelling but I stuck to my guns that that wasn't the case.
......

A good result.
You'd have known if you'd mis-fueled because your car would have come to a full stop unless you kept refueling after using just a few gallons each time.

 

[Alex Crow]

Well done you, and good to hear nice things about the main dealers, they do not always get a good press here.

Feel free to name and praise them!

 

[Boxbrownie]

Shame they didn't believe you in the first place and investigate the problem correctly.

Glad its sorted.

 

[IK320]

An update in case it is of interest.....the problem is finally sorted!

The problem got progressively worse, stalling regularly and sometimes "jolting", with a sharp drop in revs, when the engine was idling.

The main dealer had the car in a number of times and tried different things (including draining/flushing out the diesel and replacing the fuel filter) but it made no difference. The most likely reason suggested all along was damage caused by me mis-fuelling but I stuck to my guns that that wasn't the case.

This week they had the car again and noticed a slight variation in fuel pressure, it turns out I had a faulty high pressure fuel pump. They've replaced it under warranty and the car drives like a dream.

To be fair to the main dealer they've been good all along,despite making me doubt my own mind with the mis-fuelling, and have stuck at it. I've even ended up with a letter of apology for the inconvenience and £100 towards a night out as compensation!

My ML250 is currently at the dealer with the same problem being investigated. They replaced the fuel filter but it made no difference, and are now analysing the fuel as they say they suspect that is the problem. Like you I have never put the wrong fuel in the car. This is very useful evidence in case I have a problem.