[AJ9x]

Little issue I've had lately. Quick background on my situation:
Stage 2 JB4
Flex fuel wires
Catless DP
CP
CAI
6gal E85, 10 gal 92/93
Map 5
I have had an issue in the past where I was maxing my fuel trim and running a lean. Emailed BMS my logs, got a FOL suggestion and it seemed to solve most of the problem. When accelerating quickly to high speeds, I no longer get kicked to Map 4.


However, say I'm traveling 80-90mph+, staying at or near a constant speed and then I put the pedal to the ground, I'll get CEL and kicked to map 4.

My gut is telling me I'm still running lean and the sudden demand for fuel at high speeds causes me to go too lean and max my fuel trim. It only happens at high speeds. All the logs I've taken, I've never had any concerning fuel pump pressures. Any suggestions?

And before I'm asked, I'm out of town and my computer for logging is at home. If I can get any insight sans logs, that would be greatly appreciated. I can post logs when I return home later this week.

[CantCatchMe]

Trying a lower dose of E85, say 3 gallons next time. Log it and post that as well. You may need a Stage 2 lpfp to supply the 6 gallons you're running now. Post the logs as soon as you can.

[AJ9x]

Originally Posted by CantCatchMe

Trying a lower dose of E85, say 3 gallons next time. Log it and post that as well. You may need a Stage 2 lpfp to supply the 6 gallons you're running now. Post the logs as soon as you can.

Thanks, I was leaning that way. I probably won't go stage 2 lpfp until I go for stage 2 turbo.

[mike@x-ph.com]

Since you cant log at the moment, i recommend not using E85 for now

[timothy2001]

Interesting as I had a similar situation in getting 'bumped' to Map 4 from Map 5. Only happened once and I run 4 gallons of E95 to 93 octane.

I have since changed the FOL from 50 to 70 and am now going to take it to 90 on the advice of BMS and after sending in logs.

Car is running like a champ and I am not having any issues and I have a similar set up as yours just no DP.

My lpfp readings all appear solid at a consistent 87 but I am by no means an expert as I am still learning to read logs and understand how the car reacts to changes and modifications.

Interested in seeing how you make out.

[AJ9x]

Originally Posted by timothy2001

Interesting as I had a similar situation in getting 'bumped' to Map 4 from Map 5. Only happened once and I run 4 gallons of E95 to 93 octane.

I have since changed the FOL from 50 to 70 and am now going to take it to 90 on the advice of BMS and after sending in logs.

Car is running like a champ and I am not having any issues and I have a similar set up as yours just no DP.

My lpfp readings all appear solid at a consistent 87 but I am by no means an expert as I am still learning to read logs and understand how the car reacts to changes and modifications.

Interested in seeing how you make out.

Well I went from 6 gal E85 to 4 gal and the issue seems to have gone away.
seems going to go with 5 gal and if I'm good there, I'll probably keep it at 5 gal from here on out until I can upgrade the lpfp.

[msabiha2003]

Originally Posted by AJ9x

Well I went from 6 gal E85 to 4 gal and the issue seems to have gone away.
seems going to go with 5 gal and if I'm good there, I'll probably keep it at 5 gal from here on out until I can upgrade the lpfp.

i always fill with 6g of E85.
you need to check your boost limit in the user adjustment page, if its below 20 i suggest you put to 20. mine set to 21.
and then if you floor the car at the 6th gear while your RPM still low, this will create too much load and it will kick you to map 4.
plus check the FOL and raise it to 80

[E90 335xi]

Originally Posted by timothy2001

My lpfp readings all appear solid at a consistent 87 but I am by no means an expert as I am still learning to read logs and understand how the car reacts to changes and modifications.

N55s can't log the LPFP, it's one of the disadvantages vs. N54 motors.

The FP_L value will be eternally stuck at 87 but it means nothing.

[timothy2001]

Originally Posted by E90 335xi

N55s can't log the LPFP, it's one of the disadvantages vs. N54 motors.

The FP_L value will be eternally stuck at 87 but it means nothing.

Thanks for that as I do appreciate learning. I wonder if it makes sense to replace it as I plan to run e30 all the time.

[E90 335xi]

Originally Posted by timothy2001

Thanks for that as I do appreciate learning. I wonder if it makes sense to replace it as I plan to run e30 all the time.

No worries.

Go by what BMS (Terry / Steve) tell you. All cars are different and all some have stronger/weaker fuel pumps. Some cars can't even run E20 on the stock LPFP with the factory flash.

I've been fortunate enough to get away with running E50 on the stock LPFP and no BEF (back-end flash) for a whole summer, but now I can't even run straight pump gas without maxing out my trims. Tuning this thing seems to be a moving target all the time.

It's annoying but it's a small price to pay to have a car that accelerates like a Porsche Turbo, at a fraction of the price.

[timothy2001]

Originally Posted by E90 335xi

It's annoying but it's a small price to pay to have a car that accelerates like a Porsche Turbo, at a fraction of the price.

Man I couldn't agree more. It's not the top end speed, it's the rush to get there that floats my boat.