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I have a 2000 528i and posted recently regarding low fuel pressure at the rail causing the car to turn over but not start until I tried to start multiple (10++) times. I have replaced the Fuel Pump and filter (Bosch) and replaced the relay. With the information from the last post I confirmed that I had plenty of pressure 80+ PSI after the fuel filter and ~10 PSI at the rail once I reconnected the lines to the 3/2 valve assembly (Part# 13311740281 and shown in attached picture). I went to the junkyard and grabbed a replacement assembly . Once that was swapped i went form ~10 PSI to ~50 PSI and the car started on the first try for about two weeks. Then just the other day it went back to requiring me to crank on it (10++) times to get it to start.

I made a second trip out to the junkyard to get another assembly to see if that is the problem, however I find it hard to believe that I had a second unit die on me in a two week span of time. (I know it is a used part, but still seems unlikely.) Tomorrow (Saturday) I will get back under the car when I am not at work (and have daylight) to swap for the "new" unit I pulled and hopefully that will fix the issue.

My question ultimately is, has anyone swapped the newer (01+) fuel filter with the built in fuel pressure regulator into an older e39 and bypassed the 3/2 valve assembly? It seems like it could be done pretty easily and I found where it looks like some people with e36's have done it, but I may be missing something.


Link to e36 thread for reference.
https://www.bimmerforums.com/forum/showthread.php?918730-96-99-M3-Fuel-Regulator-3-2-Valve-Information
 

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Under the lift arms
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have you done a vacuum test of that leg for the regulator?
 

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have you done a vacuum test of that leg for the regulator?
I have not, can you point me to the procedure to do that?

I have done a smoke test to see if I have vacuum leaks, I ended up finding a crack in my valve cover and replaced that. Did the test again and found nothing.

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Under the lift arms
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where does that vacuum line you have circled go?
 

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where does that vacuum line you have circled go?
Was just under the car (swapping the 3/2 assembly again) this weekend and it goes up through the fender well and disappears into the engine bay. It looks like it comes out under the drivers side cabin filter. If there is daylight when I get home tonight I will pull the filter assembly to trace it further.

After replacing the 3/2 valve assembly I checked the pressure in the rail and it is the same as before, it will climb slowly to 51-52 PSI ~10 PSI at a time if I turn the ignition to accessory and give it 10 seconds or so then off and back to the accessory position.

It is still hard to start after there is proper pressure in the rail. it took me 5-6 times after I verified that there was ~52 PSI in the rail to get it to start. Then this morning I ended up killing the battery trying to get it started with ultimately no luck.


I figured with the proper pressure in the rail it should start and run for at least a few seconds before it would run lean and die if it wasn't getting enough fuel.
 

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where does that vacuum line you have circled go?
It goes to the hard line connection on the back of the fuel rail. It is a hard line built into the fuel rail that runs the length of the rail, then another vacuum hose is connected on the front of the fuel rail that snakes down and connects to the CCV/Oil separator.

That vacuum line bleeds off any fumes from the fuel pressure regulator if it fails. Pulls it all the way up to the CCV and through the separator and into the intake manifold distribution piece to be burned off.

What a dumb system, it is only on the M52TUB2.8 motors.

The large vacuum port on the back of the intake manifold drivers side is the vacuum line for the Leak Diagnosis Pump, #9 in this diagram.

https://www.realoem.com/bmw/enUS/showparts?id=DM63-USA-06-2000-E39-BMW-528i&diagId=16_0357

That vacuum line should be checked for cracks and looseness as well as the Secondary Air Pump vacuum lines that are back there.

I would do some investigation as to whether or not your fuel injectors are leaking causing the hard to start condition or some sort of
intermittent electrical gremlin.
 

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Under the lift arms
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Now we have something to move forward on to confirm...
 
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