Fuel Starvation on 250TD

Rousha

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I have had a worsening problem on my 1988 253000 mile 250TD. It started being sporadic usually when the fuel gauge was just over a quarter full but now is continuous (started at over 3/4 full and still over 1/2 tank) in that the engine runs OK for 3-4 miles and then cuts out. It starts again relunctantly and them picks up and will go for another mile or so until it stops running again. Definitely fuel starvation due to an airlock in the system but the issue is where is the problem?

I have had all the injector seals and return pipes replaced but think it might be a leak somewhere between the fuel tank and the main filter as I can see air bubbles coming up the intake pipe -could it be the fuel pump leaking or maybe the sender unit is clogged up or sticking or just a leaky union or corroded pipe?

Any ideas please?

PS I also run a 1993 300D with 171000+ on the clock
 

television

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Hello and welcome,, Most of these faults are with the fuel filter.

The tank can have some problems when one side is full, and the other empty, this causes the engine to just stop. the thing here is the a suction pipe come off the pump and the cure is to remove the pump and re fit the line that has come off and clean the pump out at the same time
 

television

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Rousha

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250Td Fuel Starvation Pronblem

You are right 1988 not 1998:Oops:

Thanks for the helpful replies -I have printed off the fuel tank diagram which could prove very useful and will try and get it sorted tomorrow. Will report back what we find?
:)
 

television

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Thanks for the helpful replies -I have printed off the fuel tank diagram which could prove very useful and will try and get it sorted tomorrow. Will report back what we find?
:)

Just for the record we have had a few pictures posted of this strainer, and they get horrible
 

SilverSaloon

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yes check the fuel tank trainer. there is a how to link knocking about for this
 

simon_wall69

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Common problem; it's probably worth replacing o rings on the fuel lines as well, as they quite commonly leak air and it's a very cheap and easy job to do.

Plenty of threads on fuel problems on w124s knocking about; many of them are mine.
 
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Rousha

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Hi Everyone,
Well the inline filter was replaced and the fuel lines blown back to the tank and the sender unit checked out. It went OK for about 100 miles and with the tank still three quarters full started playing up again. It obviously is a clogged strainer and it must be clogged fairly high up as originally the problem only arose when the tank was just over a quarter full.

Anyway instead of dropping the tank, flushing it out and cleaning the strainer I wondered if there might be a chemical solution and after doing an internet search came up with 'Soltron' a fuel enzyme conditioner which allegedly removes tank sludge, reduces harmful emissions, improves power delivery and fuel economy. So I bought some after contacting their UK agent which arrived the next day and adding a mere 30 mls (twice the usual dosage for a 16 gallon tank) filled up the tank which was just under half full. At first it wasn't plain sailing as on one or two occasions it nearly did die (as it had before due to the fuel starvation problem and an air lock in the system) but it just kept getting better and it has now done 140 miles plus and is running well. I will still be skeptical until I have used up the tank full without a recurrence but it seems to have done the trick. I will keep you all posted.
 

brianbrian

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w124 250D, SL129-deisel
I don't think you have a strainer in that 1988/ 124 model, did you change main filter as well as the small one just under air filter, take air filter of and look at the small see through filter you may have air in the system, for what it cost change fuel hoses as this needs to be done to make car reliable they do perish after 15yrs. Hope this helps let us know the outcome.
 

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