Originally Posted by mojobmw_e90

So I asked Steve is there anyway to test the dme or even pull up the fuel tables and this is what he is telling me

''You'd have to test voltage during WOT runs to see if the DME is pulling PWM to the pump''

Yeah exactly, that's what Chris already mentioned above.

Originally Posted by Martijn

Even if it does, what option do we have? Change the dme?

I'd imagine...that's pretty much the end of the line from what I understand. I believe there's a relay that supplies power to the DME itself (behind the glovebox?), so maybe that's worth looking into lol wild goose chase

#9 I think..??
https://www.realoem.com/bmw/enUS/sho...diagId=61_2220

[Martijn]

Lol indeed it is.
That's a general relay to power the dme, no?
Why would it disturb only the lpfp voltage? The rest of the car functions normal.

Originally Posted by Martijn

That's a general relay to power the dme, no?
Why would it disturb only the lpfp voltage? The rest of the car functions normal.

I agree...I'm just taking shots in the dark, that's all.

[mojobmw_e90]

Originally Posted by FCobra94

Yeah exactly, that's what Chris already mentioned above.


I'd imagine...that's pretty much the end of the line from what I understand. I believe there's a relay that supplies power to the DME itself (behind the glovebox?), so maybe that's worth looking into lol wild goose chase

#9 I think..??
https://www.realoem.com/bmw/enUS/sho...diagId=61_2220

Steve said that would be a bad idea to replace and shouldn't be messed with if it didn't fail.

[mojobmw_e90]

Originally Posted by doublespaces

Sounds like its time to go Fuel-It, if you haven't already.

In terms of what?

Originally Posted by doublespaces

Sounds like its time to go Fuel-It, if you haven't already.

You haven't been following along...that's definitely not the issue here.

[Martijn]

Im having this problem with a fuel it stage 2 pump... So... Your argument is invalid.

Originally Posted by Martijn

Im having this problem with a fuel it stage 2 pump... So... Your argument is invalid.

wtf are u talking about? OP and everyone else having issues already has a Stage 1 or Stage 2 setup, so telling them to go with an upgraded solution is pointless since one is already installed.

In other news, I switched from the MHD E40 tune (~E50 mix) to the MHD E60 tune (~E70 mix) the other day. Seems like LPFP pressures are similar even after adding more Ethanol into the tank lol go figure. HPFP is struggling a bit, so I'll probably target closer to an E60 mix next fill up to see if numbers improve:

E40
http://www.datazap.me/u/fcobra94/log...2&zoom=206-260

E60
http://www.datazap.me/u/fcobra94/log...4&zoom=135-220

[Riceball777]

Wow I have the same problem. Any answer to this?

Originally Posted by Riceball777

Wow I have the same problem. Any answer to this?

There seem to be different variations related to LPFP issues in general...given that, what exactly are you experiencing?

What tune are you running?

What fuel are you running?

Logs?

Etc.

[Martijn]

Originally Posted by FCobra94

You haven't been following along...that's definitely not the issue here.

lol, i wasn't refering to your post. i was refering to doublespaces post about switching to fuel-it. chill.

[Martijn]

Has anyone here have a anti theft system?
Because I had one. I deleted it, and after some runs the lpfp started to rise back to normal idle pressure of 75. Didn't have the possibility yet to check if it's fine up top, but at idle it's acting normal for the moment.

Update, it still drops below 50 after 6k rpm.

[Martijn]

I went from a fuel it stage 2 to a fuel it stage 1 inline pump, my problem is solved. Pressure doesn't go below 65. And idle sits at 78.

Originally Posted by Martijn

I went from a fuel it stage 2 to a fuel it stage 1 inline pump, my problem is solved. Pressure doesn't go below 65. And idle sits at 78.

Probably because that setup requires less amperage....wonder what your stage 2 pump would have done with a new EKPM.

[Martijn]

I have a new ekpm, I have new filters,... So that didn't help for me.

[dwspen01]

I have a Z4 with Hexon RR600, FBO+Inlets/Outlets, TBI and Stage 2 Fuel-It pump. Lpfp drops below 40psi above 6000 rpm with a BQ E65 Tune at 20psi. Running 20 psi on 93 oct and no TBI, pressure stays above 60psi. I will buy a used EKP and try that...do I need the dealer to code after I install?

Map of E65 is http://datazap.me/u/dwspen01/hexon-r...0&data=3-23-24

Since I have a Z4, I use a standalone LPFP sensor so it is not in the log but you see my HPFP crash above 6200 rpm to nearly 700psi.

Any suggestions would be greatly appreciated.

[RSL]

No LPFP logged? Rail pressure is your HPFP, but that's falling bad, so I'm sure LPFP is tanking. I can't believe you even stay on it that high if you know it's like that. It's probably the TBI keeping bank 1 OK, but bank 2 is down to 14:1 AFR and look at your trims. Bank 2 is pegged and running lean, you're just flat out of fuel supply. You need more LPFP or less E85, a new module isn't going to fix your issue.

Edit: Just remembered Z4's have a different setup and not sure if they have LPFP to log. Either way, judging by the HPFP curve, you're just out of fuel.

[dwspen01]

Originally Posted by RSL

No LPFP logged? Rail pressure is your HPFP, but that's falling bad, so I'm sure LPFP is tanking. I can't believe you even stay on it that high if you know it's like that. It's probably the TBI keeping bank 1 OK, but bank 2 is down to 14:1 AFR and look at your trims. Bank 2 is pegged and running lean, you're just flat out of fuel supply. You need more LPFP or less E85, a new module isn't going to fix your issue.

Edit: Just remembered Z4's have a different setup and not sure if they have LPFP to log. Either way, judging by the HPFP curve, you're just out of fuel.

You are right that the Z4s don't come with a lpfp sensor. I installed a 335i line to the HPFP with sensor fitting and installed an AEM sensor wired to a P3Cars gauge for lpfp pressure. I would have thought that I would have more than enough fuel for 23+ psi, much less 20psi, so I am trying to figure out what component is holding me back. I don't want to go PI but want to make sure I am getting what I can out of the Hexon RR600s.

[RSL]

Originally Posted by dwspen01

You are right that the Z4s don't come with a lpfp sensor. I installed a 335i line to the HPFP with sensor fitting and installed an AEM sensor wired to a P3Cars gauge for lpfp pressure. I would have thought that I would have more than enough fuel for 23+ psi, much less 20psi, so I am trying to figure out what component is holding me back. I don't want to go PI but want to make sure I am getting what I can out of the Hexon RR600s.

I don't want to derail this thread because it's about a specific issue, so start a new one for more help on your setup or just talk to BQ. It's not to say you may not have an issue related to this thread, but if FP is fine other than WOT, it just doesn't seem like it. Bank 2 wants more fuel at WOT, isn't getting it and FP is falling on it's face. Seems like a clear case of lack of supply (or too much demand) to me. While you may have upped the supply side with the Stage 2, you upped the demands on it more. I see you're only on revision 3, so things may improve some with more changes, but Stage 2 certainly isn't the end all/be all of fuel supply.

[drunkentrader]

Lots of good info in this thread - most of which my pea brain cannot comprehend.

I installed vtt gc lites and boostconepts stage 2 bucket, and recently had the lpfp code, and the power circuit(the one specific to the battery)pop up and have seen psi dip to below 40 on wot.

Running mhd stage 2+ E30. Inlets, outlets, downpipes and intercooler.

What are the odds this could be an install error that lead to a small pressure leak or electrical connection issue? Also, o2 sensor codes are present as well(my sloppy diy dp install probably killed one or both of them)

**Battery code issue and o2 sensor codes were present before lpfp and turbo install. I should also add that my hpfp may also be suspect as I’ve had intermittent issues with long starts. Does the hpfp have any direct effect on the lpfp psi?

I don’t have any logs running e30, but here was a non standard log(a few gears) running the same hardware but with mhd stage 2+ 91:

https://datazap.me/u/drunkentrader/l...g=0&data=13-23