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My 240D with 91.000 US miles on it started to lose power one day. It was running fine and I had just replaced both fuel filters about 3 months before.
I was on a short trip on the freeway when it started to buck and lose power so I got off the FW it kept losing power until I was only about to get to about 15 MPH. I would stall at stops but start right up. I limpted home and let it set a day and it started up fine ran fine for a few miles then started to lose power again. My first thougts were "fuel pump" but I wanted to ask befor going and replacing things. Anyone have some ideas?
 

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My 240D with 91.000 US miles on it started to lose power one day. It was running fine and I had just replaced both fuel filters about 3 months before.
I was on a short trip on the freeway when it started to buck and lose power so I got off the FW it kept losing power until I was only about to get to about 15 MPH. I would stall at stops but start right up. I limpted home and let it set a day and it started up fine ran fine for a few miles then started to lose power again. My first thougts were "fuel pump" but I wanted to ask befor going and replacing things. Anyone have some ideas?
When was the last time it had a valve adjustment? Maybe a vacuum leak causing the shut off valve on the injector pump to partially close and cause not enough fuel to go thru injector pump.
 

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check your fuel lines for leaks. i recently had the same issue and my fuel line connected from the fuel filter to the injection pump was worn and was leaking pretty bad thus i had little fuel pressure.
 

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check your fuel lines for leaks. i recently had the same issue and my fuel line connected from the fuel filter to the injection pump was worn and was leaking pretty bad thus i had little fuel pressure.
Have you done a diesel purge?

If you got old diesel it might clog your tank screen and or injection.
Sometimes the throttle linkage can be having an issue.

Is there other symptoms? Like smoke or chugging/jerking?
 

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No matter how new the Filters are unforunatly it only takes one fill up with contaminated Fuel to plug up the Filters or the Fuel Tank Screen.
The above is the first place to start before you suspect the Fuel Supply Pump (that is on the side of the Fuel Injection Pump).

The other issue is that there is actually stuff that can Grow inside of your Fuel Tank and that stuff will Plug up your Filters.
Addatives like Startron (for diesels) have an enzyme that eats up the dead bodies and reduces them to a size that sometimes allows them to pass through the Filter without plugging them.

But, you sell may need to have several Filters in the Trunk in order not to get stuck somewhere on the road.

You can by-pass/test the Fuel Tank Screen by swapping the positions of the Fuel Inlet Hose with the Fuel Return Hose (Cigar Hose). That also draws Fuel from a higher position in the Fuel Tank and means you need at least 1/2 Tank of Fuel.
 

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As 300Dman said, changing the direction of the hoses is a great idea, but make sure you do things in a way that will allow you to determine where is the problem. As the solutions we shared are quite simple, you may be tempted to do it all at once, and that won't let you know exactly what is going on. Beware of mechanics, they will want to change your injection pump or worse and they for sure will blame it on alternative fuels.
Good luck!
:D
 

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When the engine has been sitting and not started also check your oil level.

A low oil level will also cause the same symptoms before worse happens and it is too late.

It is rare, but ive seen it happen before.


Also when i say low i dont mean at the minimum mark i mean not showing up on the dip stick.
 

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just had the same problem with my 84' 300d on the freeway , losing power but would start and run fine after. Turns out to be an algae build up in the fuel tank, before draining fuel tank add 1 to 2 gallons of gasoline and shake around. Then drain tank and replace screen filter with new one, them change both fuel filters under the hood. Problem solved. Quick diagnostics ....replace inline plastic filter with new one and see how fast it turns black...if within 10 minutes of driving then you have an algae problem.
 
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