Fuel pump not priming on unlock SOLVED

PretendM · 10-12-2018, 08:39 PM

Hi Everyone

This is my first post!

It's about something that I have not seen answered anywhere so though I would share it here.

As the owner of an N53 engine and *that* fuel pump I'm wary of any changes in the noises that come from the fuel system. Recently I noticed that the car wasn't always making the whirring priming noise when I pressed the key fob and I could only force a really short prime by pressing the starter (key in) and clutch up.

This was worrying as the relentless priming was introduced by BMW to save the hpfp from premature failure, however the car started and ran with no problems. After some more worrying about pressure sensors etc. I remembered that I have been deactivating the stability system recently (long press on DTC button) as I've been getting a bit more er... confident with the car and it seems that weirdly, there is a connection.

After a few tests it is now predictable. If I turn the engine off with the stability system deactivated, it doesn't prime the next time the car is opened. After the next drive without any messing about(!) it's priming normally. I don't know why this would be. Having listened to some more noises, if stability is off, I can't hear the normal fuel return sound when switching off the engine so perhaps the system stays pressurised and doesn't need to prime next time.

It would be great if anyone else can prove this on other models and perhaps save some nail biting for those of us with HPFP complex

Cheers!

DaanBMW · 08-13-2019, 12:03 PM

Interesting... I only turn off the 1st stage DTC (short press), and have had a similar experience, meaning I think there is an unexpected connection between the fuel pump and the DTC. What happens on mine though is that I had the car stall 4 times now, out of the blue and w/o any pre-warning. (with code 309 - Fuel pump malfunction. I replaced both pump and regulator in the tank, same thing.). Each time DTC was off.

I'd like it understand a bit better WHY this is happening and maybe how to address it, as I do like the DTC off (have an LSD) but suddenly having no power is really scary.

DaanBMW · 08-13-2019, 12:07 PM

Oh, and BTW the N52 (mine) doesn't have a HPFP like the N53 does

10-12-2018, 08:39 PM	#1
PretendM Registered 5 Rep 1 Posts Drives: e92 330i M Sport (Manual) Join Date: Oct 2018 Location: Bedford UK iTrader: (0)	Fuel pump not priming on unlock SOLVED Hi Everyone This is my first post! It's about something that I have not seen answered anywhere so though I would share it here. As the owner of an N53 engine and that fuel pump I'm wary of any changes in the noises that come from the fuel system. Recently I noticed that the car wasn't always making the whirring priming noise when I pressed the key fob and I could only force a really short prime by pressing the starter (key in) and clutch up. This was worrying as the relentless priming was introduced by BMW to save the hpfp from premature failure, however the car started and ran with no problems. After some more worrying about pressure sensors etc. I remembered that I have been deactivating the stability system recently (long press on DTC button) as I've been getting a bit more er... confident with the car and it seems that weirdly, there is a connection. After a few tests it is now predictable. If I turn the engine off with the stability system deactivated, it doesn't prime the next time the car is opened. After the next drive without any messing about(!) it's priming normally. I don't know why this would be. Having listened to some more noises, if stability is off, I can't hear the normal fuel return sound when switching off the engine so perhaps the system stays pressurised and doesn't need to prime next time. It would be great if anyone else can prove this on other models and perhaps save some nail biting for those of us with HPFP complex Cheers!
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08-13-2019, 12:03 PM	#2
DaanBMW Captain 88 Rep 777 Posts Drives: 2007 328i coupe Join Date: Jun 2011 Location: Portland, OR iTrader: (1)	Interesting... I only turn off the 1st stage DTC (short press), and have had a similar experience, meaning I think there is an unexpected connection between the fuel pump and the DTC. What happens on mine though is that I had the car stall 4 times now, out of the blue and w/o any pre-warning. (with code 309 - Fuel pump malfunction. I replaced both pump and regulator in the tank, same thing.). Each time DTC was off. I'd like it understand a bit better WHY this is happening and maybe how to address it, as I do like the DTC off (have an LSD) but suddenly having no power is really scary. __________________ 328i Sports Pkg, Michelin PSS on Staggered 18" OZ Ultraleggeras . BMS Powerbox. Cyba scoops + Rev motoring intake hose + charcoal delete. Wavetrac LSD . M3: subframe bushings + sways + control arms (fr & rr). Meyle rear toe arms. M3 diff fr bushings . BMW Perf: v2 springs + v1 dampers. Valeo SMFW+clutch. 034 MotorSport engine mounts . Short Shifter + Turner PU bearing + ZHP M weighted shift knob. CDV delete
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08-13-2019, 12:07 PM	#3
DaanBMW Captain 88 Rep 777 Posts Drives: 2007 328i coupe Join Date: Jun 2011 Location: Portland, OR iTrader: (1)	Oh, and BTW the N52 (mine) doesn't have a HPFP like the N53 does __________________ 328i Sports Pkg, Michelin PSS on Staggered 18" OZ Ultraleggeras . BMS Powerbox. Cyba scoops + Rev motoring intake hose + charcoal delete. Wavetrac LSD . M3: subframe bushings + sways + control arms (fr & rr). Meyle rear toe arms. M3 diff fr bushings . BMW Perf: v2 springs + v1 dampers. Valeo SMFW+clutch. 034 MotorSport engine mounts . Short Shifter + Turner PU bearing + ZHP M weighted shift knob. CDV delete
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