The fuel filter is huge on the e53. It's usually good for life or 3-400,000 miles. The o-ring on the FPR is what will fail first. When that happens the symptom is hard starts.

If you have the seat up for access to the pump top you can use the percussive maintenance yourself. A rubber mallet white in the seated position.

I forgot if you're 3.0 or 4.4. The 3.0 will prime the pump at key on. Most 4.4 will wait until start to turn on the pump due to the auto crank feature.

As mentioned if the filler was plugged the fpr will just open at 50 psi and send everything back to the left tank.

MTBF on a fuel pump using E10 gas is 5000 hours. On both mine and wife's original pump that was crazy close: within 3-4%. Look at your average mph and multiply by 5000. Eg 27*5000=135000. If your odometer is over that number your pump is overdue for replacement.

If your siphon jet is still original definitely time to check it's o-ring.

I would take a jump pack or M12 battery and hotwire the pump to see if it runs with power directly applied. Rap on it at the same time. If it spins, start the car just to get it some exercise and check codes.

I had issues with the pump being a different size when i replaced just the pump and had to modify the frame.

When changing the whole assembly with discount model, the float wasn't at the same height and it changed the tank fill values.

It's imperative the foot gets into the notch in the bottom of the tank as mentioned.

The gasket on the pump assembly usually falls off during removal. It must go on the pump not the tank during assembly. I wet it with a dab of gas with a gloved finger to ease install.

It's one of the easier jobs. 3/10 difficulty hardest part is battling the seat that wants to fall on you. I opted to detach the middle seatbelt by the third time i did this job.

Fold the float up to remove vs. attempt to tip the pump sideways.


–awr–

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)