Let's fix this thing. I'm back 2003 X5 3.0

[80stech]

Very little in this thread makes sense.

[g300d]

Well, we are in E53's lol!

[Meestahbig]

So took two weeks to get my Mahle fuel filter from Pelican. Fuel filter in and my 80psi, is now reading 50psi. Drove the car 300 miles and an hour in stop and go due to a crash, no issues at all. Car has not stalled. My negative fuel trim seems better. Gas mileage is good. However, I still see the rpm bouncing a bit and the fuel economy gauge swing to the right when slowing, then move to the left. The fuel economy gauge did this on my 2006 so maybe that's normal, but the rpm bouncing is still a bit odd. I don't feel it on the car, but I've been so focussed on the rpms, I see it. It's not like the car hesitates at all or surges forward. So I'll see how that develops but I believe it's unrelated to my stalling. The stalling was at lower speeds than the bouncing rpm speed.

Now - this is the biggest mystery. The stalling was happening before the bad Hengst Fuel filter was installed by the mechanic when I was having surgery and wanted the car tuned up before a small road trip upstate to fish salmon. Then after that new fuel filter, the stalling actually got worse. So maybe this isn't quite the end of the story. Maybe the bad fuel filter just made things worse, but there is still something wrong but not presenting itself as frequently. Meanwhile, I've replaced.most other stuff with OEM parts, so only time will tell.

I'll report back after another 1000 miles. Appreciate everyone who chimed in.

[Effduration]

Originally Posted by 80stech

If it's possible to get the lines mixed up it's more likely the problem, NOT so much the filter regulator itself.

There IS a bad batch of Hengst fuel filter/regulators floating around.

About a year ago, I installed a Hengst filter /regualtor on my E39 and had a similar issue with fuel pressure going to 65psi.

[workingonit]

Originally Posted by Effduration

There IS a bad batch of Hengst fuel filter/regulators floating around.

About a year ago, I installed a Hengst filter /regualtor on my E39 and had a similar issue with fuel pressure going to 65psi.

I'm about to install a Hengst filter/regulator on my X5 (soon, if the stars align), and wonder if there's a recall on it, or some way to identify it as part of the "bad batch" before I install it?

I bought it from the Hengst "store" on Amazon on 12-20-2025, trying to acquire all the parts I needed for my fuel system refresh at the lowest cost; probably not a good idea to scrimp everywhere, especially on an old BMW.

Or on an ancient '98 Dixon ZTR 3304 mower...been patching the four tires for 28 years, and finally gave up last week, and bought $200 of new tires ($150 at Discount Tire for Carlisle knobby pneumatic rears, mounted on old wheels with service policy against flats etc, and $50 on Amazon for flat-free ribbed fronts, on new wheels). Then, the battery died yesterday (sudden death syndrome...dead cells). Can't win.

[80stech]

It must be a restriction in the assembly because if it was the regulator spring it wouldn't hold the proper pressure when the pump shuts off. Pretty crazy!

Looking at a pic of the filter it sure looks like it would be entirely possible to mix the lines up.