Help! Fuel level issue

[dougal]

When I bought my 2001 X5 3.0D 2 years ago it had an issue where when the fuel level goes below 1/4 level it starts acting as though there is a lack of fuel like difficulty starting etc..

Now its worse, its doing it with between 1/4 and 1/2 level on the gauge.

I was told in forums it could be a fuel filter or the pump between the two parts of the tank.

I went into the hidden menu in the cluster gauge, I think 6.2 and it said "TNKANZ: 74:8L PHASE2" and I read online that it could be a problem with the sender unit sensor/s.

I took it to BMW and they said that BOTH sender unit's need to be replaced and that one costs around 115 euro and the other is around 490 euros because it has a pump.

I would rather avoid such an expense. Should I replace one or both and any tips where I can get them cheaper like third party etc ? Also could they be fixed ?

[andrewwynn]

Sounds like the siphon jet is leaking. There is a design flaw (several actually) that cause the connection to leak like a sieve. Once that happens you will "run out of gas" first at 1/8 of a tank then 1/4 and more.

The electric fuel pump as it wears also gets weaker and makes it worse





e53 Fuel Supply Detailed (fuel pump / siphon pump diagnostic help)
https://r.tapatalk.com/shareLink?sha...4&share_type=t

[dougal]

Thanks, I guess that could make the most sense. Tbh I don't always trust that the dealership properly diagnose the issues. How can I check if its this and by leaking do you mean the fuel pump that is attached to one of the level sender sensors is faulty and needs replace or fix ?

Originally Posted by andrewwynn

Sounds like the siphon jet is leaking. There is a design flaw (several actually) that cause the connection to leak like a sieve. Once that happens you will "run out of gas" first at 1/8 of a tank then 1/4 and more.

The electric fuel pump as it wears also gets weaker and makes it worse





e53 Fuel Supply Detailed (fuel pump / siphon pump diagnostic help)
https://r.tapatalk.com/shareLink?sha...4&share_type=t

[andrewwynn]

Read the linked thread. It's easy to check the left side for leaks. The design flaw necessitates the replacement of the left sender unit because you have to use creative repair to fix it but you can fix for pennies (my auto-correct changed pennies to "pornos" funny enough to share)

I would recommend first fix the leaking siphon jet then test your DTE. If you can drive to zero you're done. If you can't get to zero or notice your right sender drops to zero with fuel on the left side means the pump is weak also needs replacing.

I used a knock off pump that cost me USD $120 from Amazon with a year warranty.

You can get a better actual pump by just replacing the pump itself but at this age I recommend replacing the whole sender unit.

The following thread describes how to fix the leaking siphon jet.

Siphon pump DIY repair
https://r.tapatalk.com/shareLink?sha...4&share_type=t


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