No tests today (or Yesterday after the video). I was waiting to hear back from my friend's mechanic.

Filter installed:

http://img.tapatalk.com/d/13/09/12/uheda5a3.jpg


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Does this filter have a vacuum connection at the fuel regulator?

Yes.

Side note: I was mistaken on the vacuum lines. It does only have 1 vacuum line that goes directly to the regulator, no other vacuums, as your discussion earlier stated.

I disagree, there is a check valve inside the fuel transfer system that also acts as a regulator with impact on the fuel filter/regulator itself. The o.ring inside is so easy and cheap to change that if I were diddy0071 I will give a try

Do you have an appointment set with the BMW tech?

Have you tried using the testing method in the video from upallnight? If you have not, I think it would be very helpful. If you do, do so with someone else there so you can watch and video from beginning to end. Checking the vacuum hose at the regulator for a leak as suggested before you start.

If I understand correctly, you drove 500 miles after you changed the fuel filter with no problems at all, and during that time you didn't do any work, or change any parts--just all of a sudden you had the same symptoms as before? And, nothing comes to mind that happened that same day that might be connected?

I haven't gotten a call back from BMW Tech, still waiting on that (Weekdays are busy apparently).

And here is a video of my testing from last night:

Vacuum to Pressure Reg check - YouTube

As for your last question, nothing changed, no new parts, nothing. I took the vehicle for a carwash, went on a road trip to Fresno a few days before, filled the gas tank up with fuel and that is when the problems started.

I think you have a bad fuel regulator. The fuel pressure should have gone up when you pulled the vacuum line at the F connector in the intake boot by at least 5 psi.

The reason why the fuel pressure drops when you rev the engine is because the engine uses more fuel, but since the regulator is not increasing the fuel pressure, whatever fuel in the rail is use up so the pressure drop.

Would a bad vacuum line at the regulator cause it as well?

If the vacuum line was bad you wouldn't have vacuum so the pressure regulator will treat it as a wide open throttle condition since at wide open throttle there is very little vacuum. At wide open throttle the fuel pressure will be more than at idle.

In one of my previous posts I told you you could hook up a vacuum gauge at the vacuum line attach to the fuel regulator and observe the vacuum. Vacuum should be high at idle and low when you rev the engine. This will confirm if the hose from the F connector is holding vacuum.

Since the regulator is not increasing the fuel pressure that could account for the P0171 and P0174 lean bank code since there is not enough fuel going to the cylinders at high rev. Your test of the fuel pressure at the rail verify what I just posted.

I don't have a vacuum gauge...fml. And, the pressure regulator is brand new! I replaced the old regulator/fuel filter with this one and the symptoms never changed.