e39 540 fuel problem info needed

[Boerie]

I don't know what is going on,
1st time I got the issue I flushed the fuel filter.
Would drive far distances, I see it happens when the car is warm.
1st indication is the fuel consumption indicator is sky high, then I start to feel a splatter, then it is like the car is not getting fuel. Can not start easy and when I get to start the car it is missing and can't get more than 1000 rpm out of the car, sometimes i can get with a bit of effort to maybe 4000 rpm but it misses completely.

switch off the car, wait till it is cold, then bam, nothing wrong. can do 200km/h with ease (the fact that I can get speed out of it is an indication that it might not be the fuel pump) correct ??

like i mentioned now, I changed the fuel filter, old one was dirty .

Where would you start to look? fuel pickup in tank? injectors dirty? fuel line sucking air?
Rick540 ? any comments from the guru ?

 

[Jandre]

I would guess that car is overfuelling when warm.

Dammed if I know why though.

 

[netercol]

shot in the dark, maybe a blocked tank breather?

 

[rick540]

Fuel pressure regulator

O2 Sensors

Or a blockage in the return fuel line.

Hard to say, does it smell of fuel after it has cut out (overfuelling) or is there a sharp smell that is not raw like petrol but NOX (Underfuelling).

If there is no unusual smell either way then it's electrical like a crank position sensor failing

 

[whattingh]

Have you tried to get some codes pulled?

It also sound to me it might be over fueling. My reasoning is went the car is cold you want a richer mix, think old car choke.

could be that some sensor is faulty and te car think it is running lean and try to adjust it. I think OBD might give you a clue

 

[Boerie]

yes rick, smell fuel but not to strong.

also looked at opening the fuel cap to listen for a "wwwhhooosssshhhh" sound, nothing, all normal.

 

[rick540]

Crank position sensor possibly.

they like to work when cold and fail when hot, the only way you will know is to read the codes.