[Rob_BMW_PNW]

Ok, so I am going to do a LPFP Stage 2 upgrade soon. It says I should check my LPFP to make sure it is flowing correctly.

I checked my AP and I dont have that gauge of any sort (that or I am blind).

Is there a way I can use STFT and LTFT (short and long term fuel trim) monitors to 'double check' my work and or see if the pump is working properly?

Or am I forced to get a JB4 and have it strictly for monitoring? I am getting a protune on the AP when I get my Pure Stage 2 installed, but right now I am just prepping.

I am either going with Fuel it or FPM as they have drop in kits ready to go..

Thanks ahead.

[weehe126]

N55s don't have a lpfp sensor. Only way to check is to see if your hpfp runs out of fuel.

[Rob_BMW_PNW]

How does it not? When i had my Jb4 I could log lpfp.

How do I check if my hpfp runs out of fuel? Besides it just cutting out during a pull?

[weehe126]

Originally Posted by Rob_BMW_PNW

How does it not? When i had my Jb4 I could log lpfp.

How do I check if my hpfp runs out of fuel? Besides it just cutting out during a pull?

You were logging oil temp i believe. If your hpfp goes to 900psi or less you have a problem.

[Rob_BMW_PNW]

I'm a 1000% sure it was lpfp and hpfp I was logging on the Jb4
I'll post my log when I get in the office of that

I don't have a Jb4 anymore
What gauge in the ap shows hpfp?

[Rob_BMW_PNW]

http://www.datazap.me/u/robertnguyen...data=1-4-10-17

I checked RPM, Boost, LPFP, and HPFP

This is from JB4, which I dont have anymore because I went with flash option.

[weehe126]

So you think a flat 87 "units" is your actual lpfp, no matter rpm or load?

[Rob_BMW_PNW]

Originally Posted by weehe126

So you think a flat 87 "units" is your actual lpfp, no matter rpm or load?

Then what is it? Surely not oil temp

http://www.datazap.me/u/robertnguyen...a=1-4-10-14-17

I checked the Trims box on this one. Is that it?

Can I monitor either fuel pressures with just STFT and LTFT on the ap?

http://www.n54tech.com/forums/showthread.php?t=21269

"FP L: Fuel pressure, low system. Pressure is read on the left hand scale X 10. Otherwise known as the in tank low pressure fuel pump. This value typically ranges from 55-70psi. If dropping below 50psi it indicates a problem with your low fuel pressure pump. Most often that problem is it needs to be augmented with an inline pump to keep up with the higher fuel demands required by ethanol usage.
　
FP H: Fuel pressure, high system. Otherwise known as the high pressure pump. Note all N54 include this and other platforms can only log this if also equipped with the flex fuel connector. This value represents the voltage of the high pressure 0-5V sensor, where a value of 20 is 5v. Each unit of measure is roughly equal to 150psi. Typical values at full throttle are 10-14, or 1500 to 2100psi. Values of less than 900psi as full throttle indicate a fuel delivery problem and the JB4 will failsafe at 700psi at full throttle. Note when not at full throttle a typical value is 5 or 750psi."

[bNks334]

JB4 can only log HPFP on the N55...

This is one of the highlighting points on why I am frustrated with the JB4. They don't explain this to users in any of their information threads. Why is the column filled with 87 if it's not logging? Why not code out that column of data and replace it with another useful parameter like oil pressure?

[Turbod]

The JB4 does not monitor the LPFP on the E series N55.

[Rob_BMW_PNW]

Originally Posted by bNks334

JB4 can only log HPFP on the N55...

This is one of the highlighting points on why I am frustrated with the JB4. They don't explain this to users in any of their information threads. Why is the column filled with 87 if it's not logging? Why not code out that column of data and replace it with another useful parameter like oil pressure?

https://docs.google.com/spreadsheets...gid=1137814079

LPFP changes

So, lets say LPFP sensor/logging is just a moot point and is a unreliable way to tell if the in tank system is hooked up or even working correctly

That leaves HPFP then right? We cant log this on the AP, so how do I tell when the HPFP is 'working too hard' to 'compensate' for the intank one?

I only prompted this search for the LPFP/HPFP logging because of the description here:
http://boostconcepts.net/products/fp...el-pump-bucket

"The FPM-1 P-n-P E85 Fuel Pump Bucket is the perfect solution for those 135i 335i N54 and N55 owners who are maxing out their factory low pressure fuel pump (LPFP) when running E85 fuel mixes. This fuel pump modification has been shown to effectively supply ethanol mixes higher then the High Pressure Fuel Pump (HPFP) can adequately utilize. Appropriate logging should be used to verify system performance and to ensure the the LPFP and HPFP are operating within acceptable ranges. Based on reports and Datalogs supplied during the Beta Testing, this configuration was capable of E60-E70 mixes depending on the health and age of the HPFP. Your results may vary."

Id assume it would be the same for the Fuel-It! fuel pump assembly too, have to check logs to make sure everything is fine. Someone on the Facebook page did a DIY 450 pump and his LPFP was very very low because of a kinked line (so he thought, it was actually a LPFP sensor), but the car drove fine and HPFP looked fine.

[Rob_BMW_PNW]

Also, I am only using Jb4 as a reference, I dont want to use it at all to be honest. I am not sure what to monitor on my AP to see that my fuel pressures from both pumps are 'fine'
The only thing I can see is STFT and LTFT, if there is a way to correlate/interpret those two, to the pressure of the pumps, Id like to know.

I cant be the only one who is flash only tuned with a soon to be upgraded pump lol

[MiamiM3]

This is what I asked Dzenno a while back. I am running E50 with PTF protune:

What are safe limits for STFT and LTFT. What the number limits that I need to look for?

They are maxed at 33% in either + or - direction. Ideally below 20 on average.

[Rob_BMW_PNW]

Originally Posted by MiamiM3

This is what I asked Dzenno a while back. I am running E50 with PTF protune:

What are safe limits for STFT and LTFT. What the number limits that I need to look for?

They are maxed at 33% in either + or - direction. Ideally below 20 on average.

Thanks.

Still doesn't show HPFP pressure though. Maybe Cobb will add it one day, or MHD will finally just come out