[Lee_EnfieldNo.4]

Long Explanation Time (great first post I suppose)

I have a 2016 535D with about 127,000 KM (80,000ish miles) and am concerned about the HPFP being starved from gelled fuel.

Basically, it hit around -40C (-40F, its just cold...) here a few days ago and I was mid road trip. Average temp was around -35 but parts did dip to -40. We use Winter diesel around here and I add Optilube XPD year round that also has Anti-gel in it. But, I think I still had the fuel partially Gel. I heard a whine coming form the rear of the cabin On the way home, and when I got into my driveway I could hear it from the outside.

I didn't think it was the fuel pump since I shut off the engine, and re started and it didn't come back till a few seconds after start so I chalked it up to its -40 degrees and nothing is happy right now. The car started and drove just fine. Figured gelled fuel would block flow completely.

Put the car I the warm(er) garage (around -8) and started it up in the morning, sound was gone.

Just to make sure I read the faults and there was a stored fault of "low delivery pressure" and a high power consumption for fuel pump fault logged Around the KM when I was driving.

Only thing I noticed about performace that's giving me cause is was on low load (coasting or down hill) at low RPM, if I applied light throttle it would jutter a little, but I read other have this issue and it was doing that before I had the low pressure faults, so that might be another issue...

No Other fuel related faults, (I think the battery is toast as lots of low voltage faults though) starts right up in a few cranks, Fuel mileage is lower then normal but the winter diesel is known for that and the extreme cold as well. Bit of vibration when its outside, but once again at -35 the engine mounts might as well be solids...

So, is my HPFP about to fail?

Thanks

[BimmerHausPerformance]

No way to know if it starved without waiting for it to fail. You could go to your HPFP and pull the regulator on it and see if there is any metal shavings in that little filter there. But if you do see any, by then it's usually toast. They sell set ups that don't allow the damage to go throughout the fuel system if your pump does go. Maybe you should look into that.

[T-Dubbs]

Ive never had an issue with gelled diesel in Canada in -40c.

is the car up to date with maintenance?

[Lee_EnfieldNo.4]

I like to think the car is maintained, I try to do all the consumables and fluids on time and took it into a specialist shop for a once over as well.

Reason i suspect partially gelled fuel was the temperature, the whine noise from the pump area that went away when it warmed up, and the fault code stored for low delivery fuel pressure from the LP pump.

[Lee_EnfieldNo.4]

Ok,

It's been a few weeks and no issues.

But the whine noise came back just now. It's not super cold so my theory about gelled fuel is likely wrong.

Could the low pressure fuel pump just be on the way out?

The noise is not there at first but comes back after a few seconds of running. Sound kinda pulses at first then steadies out.

[iBonsai]

Please tell me your solved this!!! I’m having the same issue in my 14 535d. Low delivery pressure codes. Bled the fuel system through itsa. But Same issue. I think I notice it more when cold. And more when the tank level is lower. It’s a new fuel filter. Not sure if it’s the heating element, low pressure pump or one of the pressure or temp sensors.

[Lee_EnfieldNo.4]

Originally Posted by iBonsai

Please tell me your solved this!!! I’m having the same issue in my 14 535d. Low delivery pressure codes. Bled the fuel system through itsa. But Same issue. I think I notice it more when cold. And more when the tank level is lower. It’s a new fuel filter. Not sure if it’s the heating element, low pressure pump or one of the pressure or temp sensors.

Im fairly certain I have a failing electric fuel pump. Low pressure warnings, high current draw, and a whining noise all point to a failing electric pump to me.

Car only has 130000KM (80,000 Miles) so kind of a bummer.