Fuel Pressure issue - FPR

[Leo_328i]

Hey guys,

I'm still in the process of diagnosing a nasty issue with my M52 B28 and it seems to be fuel related.

I had a spare fuel rail out of an E36 320i (M50) and when I pulled the FPR it had '3.0 bar' written on it. Now I've read that all the M50 motors have the same FPR and even the RealOEM part numbers suggest this as well but I only just realised that there may have been a flaw in my thinking.

The M50B20 motor came to the USA so perhaps the 2.0l motor has a lower pressure regulator? My M52B28 doesn't seem to be getting enough fuel pressure as when we squeeze the fuel return line the car runs as it should, but when you let go the car fails to idle properly and the car also pings at WOT.

So my question is - is a M52B28 motor supposed to have a 3.0 bar or 3.5 bar regulator? Does anyone have a DEFINITE answer to this? I keep hearing 3.0bar and 3.5bar being thrown around in different threads and need an definite answer please! :)

[yanal]

I have a complete M50B28 in my garage, I'll check it tomorrow if you still need an answer by then, but a dump thought for the moment, did you connect the vacuum line to the fpr ? I always forget to connect it as its hidden underneath and I get the same symptoms

[Leo_328i]

Vanal, if you could do that, that would be awesome. Definitely will still need an answer tomorrow. It is a bit of a bitch to remove the regulator from the rail but I would really appreciate it if you did!

[Wanganstyle]

M52b28 shipped from bmw factory with a 3.5bar regulator. All markets got the same 3.5 bar FPR: part number 13531436110

[dubseven]

yep 3.5 bar

[Leo_328i]

Legendary, thanks guys!