Originally Posted by andrewwynn

On the e 53 the jet pump fails when a dream opens up and gas comes out the side.

I've rebuilt a few of them. My e 70 isn't as old but i don't know if BMW fixed the m design defect that causes the issue.

Three symptoms almost exactly match jet pump failure.

If on level ground the right side drops below ≈ 1.4L that's the tell.

On the e 53 the transition point is about 27L left it seems far too coincidental that you're at 30. The tanks are different so that might be the transition point.

I can pull up test six and learn what the normal values are for the e 70. I "wow the book" on the e 53 fuel transfer when i fixed both of ours they both failed exactly the same way.

The 53 has a much more lopsided tank with left much bigger.

It also has a deep well for the pump on the right side and holds zero L of fuel on the right after the transition point.

There's a lot for me to learn on the 70 before i can rule with authority but if the transition point of breaking left from right is 30L, odds are nearly 100% jet pump failure.


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