RESOLVED! 29E2 and 29F2 Codes and Half Engine Limp Mode

[user2688]

Hey guys!

Just thought I'd post this here for others that may come across the same problem since I searched for quite a while until I found the solution.

I have an '09 135i with the HPFP recall done, dual cone intake, downpipes and JB4.

This happened to me the first time a few months ago when I tried topping the car. I was going around 220 km/h in 5th gear WOT when suddenly I felt like the car hit a wall... half engine light went on fans at full speed, etc. Initially I thought I blew the charge pipe because of the jolt but after inspection everything seemed fine, restarted the car and I was good to go. Then it happened again in 4th gear, and again in 5th gear and again, and again. Only at WOT and only in 4th gear and up at high rpm and high speed.
Changing from map 5 to map 1 or 2 didn't do anything.
Here is exactly what I was getting:
https://www.youtube.com/watch?v=FELK45QRX_Q



Most posts i found said it was faulty injectors or spark plugs, or even the HPFP!
Finally before bringing the car to the dealership for a $135 "diagnostic", I found this (read the whole thing!):
http://www.n54tech.com/forums/showthread.php?t=19997
also read: http://www.n54tech.com/forums/showpo...75&postcount=1 and read the part about FOL (Fuel Open Loop)

TL;DR If you are getting these errors, lower the Open Loop setting either by USB or with the steering wheel controls. Mine was at 94 and since lowering it to 70 all my troubles have went away!

[Cozy]

Well I don't have a JB4 which I guess your issue was related to but I wanted to say thanks for posting this up as this stuff is really helpful. All too often these types of posts get buried with no replies while the 100th DV thread bumps up regularly.

I hope this helps someone out in the future

[135er]

How much was it at initially ? Mine was at 80 and i have the same issues you had.

[user2688]

94... also what gas do you use? For me the whole issue began when I started putting Petro Canada "94 octane" which so happens to contain 10% ethanol... thanks you bastards!!!

[135er]

I use shell V power.. im still having the same issue at WOT at 200 KMH.

Car is going to the dealer thursday anyways

[I35it]

I just wanted to say thank you because so far this has resolved my issue. My open loop was at 50 before.

[135er]

HPFP is getting changed finally...

[ATTN]

This is excellent information.

I'm a e92 335 FBO + 30/70 E85 platform and I am also experiencing the same problem on 4th gear pulls. It's only ever happened to me twice on 4th gear WOT, both times on the dyno funny enough.

Fisrt time CEL I wasn't running e85, there wasn't any fault codes that I could find via jb4, I just assumed maybe injectors.

Second time it happened which was actually today,i checked for codes straight away, faults read;

29F2
29E2

After reading this thread via Google search, I've checked my 'user adjustments' on my JB4 my FOL looks like it's set on 95. I might lower it by increments of 5? and see how I go or straight to 70?

[BMSE92_Harry]

With 29E2 and 29F2.. does it mean the LPFP and HPFP will need to be replaced soon?

Also, will getting a fuel it inline or stage 2 bump help remedy this situation?

[user2688]

Originally Posted by Harrychiu012

With 29E2 and 29F2.. does it mean the LPFP and HPFP will need to be replaced soon?

Also, will getting a fuel it inline or stage 2 bump help remedy this situation?

The codes don't necessarily mean your fuel pump is failing. When are you getting the codes to come on? Are you getting the half engine light (limp mode) ?

What kind of gas are you using? If you use gas that has a high ethanol content it may be the root of the issue.

The problem with ethanol lies in stoichiometry. Pure ethanol has a stoichiometric AFR of 9:1 whereas regular gasoline has an AFR of 14.7:1.

In other words (correct me if I'm wrong) you need 14.7 units of mass of air for one unit of mass of gas, 1 gram of gasoline burns with 14.7 grams of air.
For ethanol, you can burn less air with the same amount (9 parts air for one part pure ethanol). Naturally, the engine has to compensate by adding MORE fuel for each ignition cycle.

In our situation this translates into more work for a fuel pump which is being already used above standard specifications (if you have JB4 or any other tuner). At some point, the fuel pump cannot sufficiently increase the pressure to obtain the correct amount of gas injected for each cycle and you get a fuel pressure error.

JB4 works by tricking the car's computer into thinking the fuel pressure is lower than it actually is to get it to increase it to what the computer thinks is a "normal" level. If the fuel pressure increase necessary is too great, it causes the computer to think the pressure is WAY too low for normal operating conditions and you get your error code and limp mode.


Therefore, try to keep to zero ethanol gas.

[BMSE92_Harry]

I was running E30 on JB4 Map5 FBO without the FMIC.
I had run E30 on Map5 without issue before, and this time it happened right after I fueled up my tank with e85 approximately 30% and going WOT from 3->4 and 4->5 gear.

I ran it on Map2 and it seems to be okay, and that is when I adjusted the FOL back to 75.

[rhodesman]

I can back the OP on this also. Exact same issue, posted my logs to N54Tech, and everyone said to lower my FOL, was at 93-95. Lowered it to 80 and been golden ever since!

Definitely worth a try.

[BMSE92_Harry]

I've lowered the FOL to 80, but JB4 MAP 5 autotuned and readjusted the FOL to 90 by itself.. does that mean I cannot run it on map 5?

[2010MSPORT335i]

This happened to me last night as well. What are the side effects of lowering this? Currently I'm running Map 5 FOL 94

[rhodesman]

Originally Posted by Harrychiu012

I've lowered the FOL to 80, but JB4 MAP 5 autotuned and readjusted the FOL to 90 by itself.. does that mean I cannot run it on map 5?

What's map 5 putting your boost at? It maybe something else entirely.

[BMSE92_Harry]

Map 5 i'm running around 17-18 ish psi tapered to 17

[chichicastenango]

Originally Posted by user2688

Hey guys!

Just thought I'd post this here for others that may come across the same problem since I searched for quite a while until I found the solution.

I have an '09 135i with the HPFP recall done, dual cone intake, downpipes and JB4.

This happened to me the first time a few months ago when I tried topping the car. I was going around 220 km/h in 5th gear WOT when suddenly I felt like the car hit a wall... half engine light went on fans at full speed, etc. Initially I thought I blew the charge pipe because of the jolt but after inspection everything seemed fine, restarted the car and I was good to go. Then it happened again in 4th gear, and again in 5th gear and again, and again. Only at WOT and only in 4th gear and up at high rpm and high speed.
Changing from map 5 to map 1 or 2 didn't do anything.
Here is exactly what I was getting:
https://www.youtube.com/watch?v=FELK45QRX_Q



Most posts i found said it was faulty injectors or spark plugs, or even the HPFP!
Finally before bringing the car to the dealership for a $135 "diagnostic", I found this (read the whole thing!):
http://www.n54tech.com/forums/showthread.php?t=19997
also read: http://www.n54tech.com/forums/showpo...75&postcount=1 and read the part about FOL (Fuel Open Loop)

TL;DR If you are getting these errors, lower the Open Loop setting either by USB or with the steering wheel controls. Mine was at 94 and since lowering it to 70 all my troubles have went away!

Hey, sorry to drag up an old post, but I'm having a similar issue and the links you posted are no longer active. I'm not really mechanically inclined either so if anyone can run me through how to fix this, I'd appreciate it.

[supadups2k18]

Hello all,

I am seeing the same error codes and see the activity in the attached video when starting my car. Any ideas on what the issue could be? I took it in to the European car specialist and he is telling me I need to leave the car a few days for him to figure out what it is. WTF?

Https://drive.google.com/file/d/1_Jj...w?usp=drivesdk

[chuyser]

Originally Posted by rhodesman

I can back the OP on this also. Exact same issue, posted my logs to N54Tech, and everyone said to lower my FOL, was at 93-95. Lowered it to 80 and been golden ever since!

Definitely worth a try.

if you can please walk me through how to lower the fol that would be amazing!!