[Mr.328i]

2012 328i, N20 engine. When cold, car starts up completely fine, i can drive off no issues. However after about 20-30 minutes of normal traffic driving car loses fuel rail pressure and throws a low fuel rail pressure warning and drivetrain error. main code - P0087. The pressure drops to 1200kPa on idle and rises to around 1500kPa under acceleration. Keep in mind that when the car is fine its FINE i can pull to redline and has no issues maintaining the 7000kPa when idle and 20000kPa under acceleration. This tells me the hpfp cannot have failed as its a purely mechanical component and wouldnt work at all if it had gone bad. If i turn the car off and restart after a while the issue goes away and i can drive iff as normal. I have put a heatsink on the EKPM mosfet and a blower fan on the module so it cant be overheating, and the lpfp had been replaced last year due to a leak in the orignal(not genuine bmw pump). I think it’s the fuel rail pressure sensor. Any help would be greatly appreciated! Thanks

[Shirazkhan]

Get a fuel pressure gauge and check the pressure from the lpfp.