Poor fuel consumption X5 diesel

[514.X5]

Hi

I have been getting poor fuel consumption on my 2011 35d X5. it struggles to stay under 10L/100km. ı mostly do highway and cruise at 100km/h most of the time. I know she can do better than that sure.

-Replaced the thermostat that was staying open.
-Did a DPF delete and tune, I really thought that would help but was not noticeable.
-Did a carbon cleanup 2 weeks ago that eliminates carbon build on diesel/gas engines. No positive results.
-Air filter is clean.

What else could I check or what worked for you?

Thanks

[andrewwynn]

Have you measured the consumption at the pump or just relying on the obc dashboard numbers? The dash number is not always accurate and can be calibrated of it's off.

That said, diesel's often have a performance problem if their vaccum reservoir leaks. You can use a vacuum pump to test but real world test is climb a long hill under power. The turbo will give up if the vaccum is leaking.

First though, run though a good part of the tank fill up and measure and do the math.


–awr–

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[514.X5]

I usually rely on the dash board but also always reset my km counter when I fill up the tank. I get around 850 km on a full tank maybe 900 if i really stretch the limits. Thats ruffly 10L per 100km as the tank is about 83 liters more or less. That makes me think the dashboard is not off.

When you say the turbo will give up are you talking about limp mode? I know for a fact that if i push the engine aggressively and drive fast it gets into a mode where you can drive with a very restricted power output until the car has been shutoff and restarted.

Maybe the vacuum reservoir need to be checked?

[andrewwynn]

If you drive hard and it kicks in limp mode something is definitely wrong.

Yes definitely check the vacuum reservoir.

The typical symptom of the vacuum reservoir failing is you lose power going up a long hill.


–awr–

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