2012 BMW 335i N55 - Long Crank and Stumble - P0087 Fuel Pressure Low

Question

Lately, my E92 has been taking 5-7 seconds to start in the morning. Once it's running, it feels okay around town, but the second I try to merge onto the highway and go wide-open throttle, the 'Drivetrain Malfunction' light pops up and the car goes into a reduced power mode.

I scanned it and got P0087 (Fuel rail pressure too low). I'm worried it's the High-Pressure Fuel Pump (HPFP), but I thought those issues were mostly on the older N54 engines. Could it just be a fuel pressure sensor or the in-tank pump?

BigRigBenny · Accepted Answer

✅ Confirmed fix: It was the High-Pressure Fuel Pump (HPFP). Despite the N55 being more reliable than the N54, the internal seals on these pumps still fail, leading to internal leakage and inability to maintain rail pressure during the cold-start prime or high-load demands. Real-time data showed rail pressure at only 700 PSI under load when it should have been closer to 2000+ PSI. Replaced the pump and the car starts instantly now.

BoostedBryan · Answer

Log your low-pressure fuel system (LPFP) while driving. If the lift pump in the tank is dropping below 5 bar under load, that's your culprit. Usually, if the HPFP is failing, you'll see the rail pressure deviate significantly from the 'target' pressure in your logging software.

2012 BMW 335i N55 - Long Crank and Stumble - P0087 Fuel Pressure Low

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