Low Fuel Pressure jumps

RomanK · 12-16-2013, 12:59 PM

Hello guys.

Sorry for my English...

I have the BMW 335i 2007. N54 engine.

I have the problem with acceleration. When I try to accelerate I get "Engine Fault, reduced power" message.

I will not describe all my feels, I will ask only concretely question.

I have the error messages: 2AAF, 29DC, 29F2 and sometimes ago I had the 2FBF... but now it doesn't appear...

I take a logs of my fuel pressures.

This is the first:

At the beginning of the graph is the acceleration.

Red line - low pressure
Blue line - high pressure
Green line - RPM.

It is obvious, that when I tried to accelerate, my high pressure is going down! So, I suppose that my HPFP died.

But my question is: is it correct that low pressure can has such noise under acceleration??? Why the pressure has such jumps?

One more log for more understanding:

I already ordered the HFPF but I think that my fuel regulator at the fuel tank also died.

What do you think?

Thanks!

Best Regards, Roman

enrita · 12-16-2013, 01:32 PM

Search for the codes for answers...

RomanK · 12-16-2013, 01:42 PM

I know the info about these codes... I would like to know about the low pressure. Should it be so noisy under acceleration or not? Without acceleration it holds 5.7 bar without any problems.

enrita · 12-16-2013, 02:03 PM

Than post what the codes means... Do u think people here know all codes by heart???????
At least make an effort...

RomanK · 12-16-2013, 02:21 PM

Ok. Sorry...

2AAF - Fuel pump, plausibility
29DC - Cyl. injection switch-off
29F2 - Fuel high pressure system, fuel pressure
2FBF - Fuel pressure at injection release

dx1541 · 12-16-2013, 05:19 PM

HPFP going out if you asked me, what fuel are you running on?

RomanK · 12-17-2013, 09:46 AM

I use 98 gasoline in Russia.

Yes, I already ordered the HPFP.. but my question is: Is it correct that low pressure can has such noise under acceleration? Why the pressure has such jumps?

dx1541 · 01-17-2014, 09:02 AM

Funny howi have nearly the exact same problem as yours. Before the 29DC , I kept getting 29F3, in one instance I had a 29F2 captured in series on my Cobb AP. Similarly when I try to accelerate I get half engine light and the car would go into fault saying reduced power on the IDrive.
What I did first was to address the LPFP pressure sensor right before the hpfp in the engine bay. That fixed it altogether.

But as much as those are gone I am now getting a 29DC fault with 2AAF ( this is common ) and harmless. This is the tough one. I am running E60 so they say its due to that but the puzzling problem is that I once ran pure E85 and it was fine then.

Am running a new 480 l/hr custom E85 only GM LPFP pump and my pressures stay above 70 psi constant.

Change your lpfp sensor first, next will be hpfp if you are still having issues.

Hell I am contemplating a second hpfp but then again I have no symptoms of an hpfp trouble.

Good luck.

12-16-2013, 12:59 PM	#1
RomanK Private First Class 46 Rep 136 Posts Drives: M3 Coupe E92 DCT Join Date: Dec 2013 Location: St. Petersburg iTrader: (0)	Low Fuel Pressure jumps Hello guys. Sorry for my English... I have the BMW 335i 2007. N54 engine. I have the problem with acceleration. When I try to accelerate I get "Engine Fault, reduced power" message. I will not describe all my feels, I will ask only concretely question. I have the error messages: 2AAF, 29DC, 29F2 and sometimes ago I had the 2FBF... but now it doesn't appear... I take a logs of my fuel pressures. This is the first: At the beginning of the graph is the acceleration. Red line - low pressure Blue line - high pressure Green line - RPM. It is obvious, that when I tried to accelerate, my high pressure is going down! So, I suppose that my HPFP died. But my question is: is it correct that low pressure can has such noise under acceleration??? Why the pressure has such jumps? One more log for more understanding: I already ordered the HFPF but I think that my fuel regulator at the fuel tank also died. What do you think? Thanks! Best Regards, Roman
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12-16-2013, 01:32 PM	#2
enrita Major General 161 Rep 7,377 Posts Drives: 335i - Big turbos Join Date: Sep 2008 Location: Italian in Sweden iTrader: (0)	Search for the codes for answers...
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12-16-2013, 01:42 PM	#3
RomanK Private First Class 46 Rep 136 Posts Drives: M3 Coupe E92 DCT Join Date: Dec 2013 Location: St. Petersburg iTrader: (0)	I know the info about these codes... I would like to know about the low pressure. Should it be so noisy under acceleration or not? Without acceleration it holds 5.7 bar without any problems.
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12-16-2013, 02:03 PM	#4
enrita Major General 161 Rep 7,377 Posts Drives: 335i - Big turbos Join Date: Sep 2008 Location: Italian in Sweden iTrader: (0)	Than post what the codes means... Do u think people here know all codes by heart??????? At least make an effort...
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12-16-2013, 02:21 PM	#5
RomanK Private First Class 46 Rep 136 Posts Drives: M3 Coupe E92 DCT Join Date: Dec 2013 Location: St. Petersburg iTrader: (0)	Ok. Sorry... 2AAF - Fuel pump, plausibility 29DC - Cyl. injection switch-off 29F2 - Fuel high pressure system, fuel pressure 2FBF - Fuel pressure at injection release
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12-16-2013, 05:19 PM	#6
dx1541 First Lieutenant 9 Rep 305 Posts Drives: E92 335is blue water metallic Join Date: Jun 2013 Location: Malaysia iTrader: (1)	HPFP going out if you asked me, what fuel are you running on?
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12-17-2013, 09:46 AM	#7
RomanK Private First Class 46 Rep 136 Posts Drives: M3 Coupe E92 DCT Join Date: Dec 2013 Location: St. Petersburg iTrader: (0)	I use 98 gasoline in Russia. Yes, I already ordered the HPFP.. but my question is: Is it correct that low pressure can has such noise under acceleration? Why the pressure has such jumps?
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01-17-2014, 09:02 AM	#8
dx1541 First Lieutenant 9 Rep 305 Posts Drives: E92 335is blue water metallic Join Date: Jun 2013 Location: Malaysia iTrader: (1)	Funny howi have nearly the exact same problem as yours. Before the 29DC , I kept getting 29F3, in one instance I had a 29F2 captured in series on my Cobb AP. Similarly when I try to accelerate I get half engine light and the car would go into fault saying reduced power on the IDrive. What I did first was to address the LPFP pressure sensor right before the hpfp in the engine bay. That fixed it altogether. But as much as those are gone I am now getting a 29DC fault with 2AAF ( this is common ) and harmless. This is the tough one. I am running E60 so they say its due to that but the puzzling problem is that I once ran pure E85 and it was fine then. Am running a new 480 l/hr custom E85 only GM LPFP pump and my pressures stay above 70 psi constant. Change your lpfp sensor first, next will be hpfp if you are still having issues. Hell I am contemplating a second hpfp but then again I have no symptoms of an hpfp trouble. Good luck.
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