[kanecvl]

Im getting the under boost code at partial throttle proceded by limp mode around 3k to 4500rpms. I also get cylinder 6 misfire w.o.t usually going from 4th to 5th gear and sometimes 3rd to 4th. I have new plugs,injectors, and swapped coils. The under boost code has just become a problem. For the last year I have been having cylinder 6 misfire. Originally I had v2 I now have v4 with the latest maps. Without the tune on I have no codes. If anyone has had similar problem please chime in. I am scheduled to have the car tested for boost leaks next week. Thanks in advance everyone.

[AltecBX]

I had similar misfires in older maps. I never got around to changing plugs, but the new maps (after may sometime) seem to fix the problem. It happened only over 5900rpm for me.

[kanecvl]

My misfire is at redline

[Bimmer This]

I had the same problem. I tend to misfire under high boost. Are you V4 with AT?

[tcrow31]

I have misfire on 5 under boost. Usually 3rd to 4th around 5k rpms. When the check engine light came on I took it straight to dealer and they replaced 3 injectors and spark plugs. Now it happens at about 6k rpms (I was testing out the car after I left dealer). But since I dont rev it that high I will just live with it for now.

[kanecvl]

Originally Posted by Bimmer This

I had the same problem. I tend to misfire under high boost. Are you V4 with AT?

yep v4 AT

[kanecvl]

Originally Posted by tcrow31

I have misfire on 5 under boost. Usually 3rd to 4th around 5k rpms. When the check engine light came on I took it straight to dealer and they replaced 3 injectors and spark plugs. Now it happens at about 6k rpms (I was testing out the car after I left dealer). But since I dont rev it that high I will just live with it for now.

are you tuned?

[tcrow31]

Originally Posted by kanecvl

are you tuned?

No tune bone stock.

[kanecvl]

bump

[Bimmer This]

Originally Posted by kanecvl

yep v4 AT

New software should adress the misfire issues with us AT guys. Yesterday, I manually shifted right before redline and misfired but that was probably pushing it too close to redline.

[badass335]

I always got the misfires on cyl 6 mostly and sometimes 5 & 6 when i ran procede. It was always over 6000rpm for me. It got so frustrating since i tried pretty much everything. I took my car in fully modded to dealership and as usual, they blamed the software. Take it out, and no issues. I replaced plugs myself, coil packs and paid for cyl6 injector as well. Still had it. Shiv was awesome in his efforts to troubleshoot it with me but i finally gave up. Procede and my car just had no love and i had to accept that.

[kanecvl]

Originally Posted by badass335

I always got the misfires on cyl 6 mostly and sometimes 5 & 6 when i ran procede. It was always over 6000rpm for me. It got so frustrating since i tried pretty much everything. I took my car in fully modded to dealership and as usual, they blamed the software. Take it out, and no issues. I replaced plugs myself, coil packs and paid for cyl6 injector as well. Still had it. Shiv was awesome in his efforts to troubleshoot it with me but i finally gave up. Procede and my car just had no love and i had to accept that.

That's the point I'm getting to now. However I am being led to believe that my problem is unique. If it turns out I don't have a leak. I'm going for another tune. I'v lost a lot of money and time trying to fix this. Probably should have just gotten a flash. Ess tune is lookin real good right now. My misfire is always near redline or right at redline

[hun77777]

Originally Posted by kanecvl

That's the point I'm getting to now. However I am being led to believe that my problem is unique. If it turns out I don't have a leak. I'm going for another tune. I'v lost a lot of money and time trying to fix this. Probably should have just gotten a flash. Ess tune is lookin real good right now

i had exact same issue which i initially believe that it was spark plug / coil pack as shiv suggested. replaced plug and swapped around the coil but misfire still persists and it only happens at redline. misfiring was still present under valet mode which lead to believe it's not a procede that's causing this problem. talked to few bmw techs including two master tech and one lead tech at the dealership and they told me hpfp is more probable than injector so i went ahead and drop the car at the dealership to have that lead tech to take a look at it. he discovered that there's fuel pump code (10739/29F3 - Fuel pressure sensor, electrical) but it's not hpfp related, it was lpfp low pressure sensor went wrong. SA came by me with the tab totalling whopping $600 after tax. i said no. the lead tech loaded up the newest software program which supposedly help hpfp issue at no extra cost to me because it's under their open campaign / recall. so that was yesterday.

i just repaired this problem at local independent bmw shop and my problem went away. i pushed the car pretty hard and it shifts from 2-3-4-5 no problem all the way up to 150mph (of course i was in private road down mexico ). if u want more to it, i already post this up under this link below. hope this helps.

http://www.e90post.com/forums/showthread.php?t=421345

suggestion to op - see if the misfiring problem still persists on valet mode. if it's not doing it when in valet, it might not be the same case as mine but if it still does it, then (since u already replaced spark plug, coil, injector), i would take a look at hpfp and lpfp low pressure sensor. the tech at the dealership told me it is VERY COMMON to see people with N54 platform bring their car with bad lpfp low pressure sensor, but 99% of them are still in warranty and if they are pissed off about long crank or whatnot, dealership usually go ahead and grant to fix not only lpfp low pressure sensor but also hpfp... i miss my 50k warranty

[badass335]

In my car, i would never get misfires on valet mode. I actually switched to JB3 and no problems. I'm going with GIAC most likely but i had the jb3 kicking around so threw it in and no issues at all. I'm just spending on suspension right now so setting priorities. My car is a stage 3 pretty much maxed out on mods. I got so frustrated with misfires as you'd never know when it would happen. I'd be scared to race it or worse yet, my wife wouldn't touch my car as the 'engine thingamaboby light' comes on and the car shakes like crazy. (Her words)

I took my fully modded car into the dealers so they could look at it. Everything always checked out it seemed.

[kanecvl]

I have the can clear off so all code should remain. Taking it back to the shop today. If I have to make another guess on a problem (coil,injector,etc) i'l just get flashed I thought about giac also. When I take the tune off no problems. I never pushed it with valet.

[hun77777]

Originally Posted by kanecvl

I have the can clear off so all code should remain. Taking it back to the shop today. If I have to make another guess on a problem (coil,injector,etc) i'l just get flashed I thought about giac also. When I take the tune off no problems. I never pushed it with valet.

if it is indeed lpfp low pressure sensor failing like my case, it doesn't matter whether you have piggy or flash. misfire will happen again because it's more of a actual hardware issue. simple test would be turn it down to valet mode and floor it through 2-3-4 to see if it still misfires. if it does misfire, i'll have your mechanic to take a look at fuel pressure on both hpfp and lpfp and go from there.

according to bmw lead tech, in case of fuel pump failure (either hpfp or lpfp), misfire on cylinder 5 and 6 is common symptom because of the location of fuel pump and line being close to those cylinder (or somewhere along that line; i didn't exactly remember because i wasn't really paying attention. correct me if i'm wrong )

do you have long crank at all?

[kanecvl]

I haven't had any long cranks, and can only get the misfire at the top of 3rd and 4th (100 & 130mph)

[kanecvl]

This problem is a year old. If it was hpfp or lpfp I think it would have went dead by now. Same prob with previous version of this tune (rev 2) it was more random then or should I say everytime. I received the v4 originally with something broke(rattled) inside from shipping. That unit never gave me misfire. Upon receiving a non-faulty unit I started getting misfire again and underboost codes. It is good to know that my problem is not 1 in a million.

[alextremo]

I'd continue looking for a mechanical issue if it were me. 5 guys posted here who experienced a similar issue, including 1 stock and 1 who fixed the mechanical problem so not sure that qualifies as an indictment of the PROcede. I've been running PROcede for ~35k miles (v3 and v4) and I've never experienced limp or misfire at redline or otherwise on my 6AT.

It's not surprising to me that a tune can magnify the symptoms of mechanical failure as you're asking a lot more out of the car. My guess is this is why people sometimes see issues "disappear" when they take out the tune. In reality the issues are likely still there, just not as evident when not increasing boost/fuel/timing past OEM levels.



Just my .02 - hope you get everything worked out, this must be frustrating for you...

[Chefcg1]

I have been running V4 procede with no issues with miss fire at all. I would guess an under boost code would be a boost leak which at lower boost (stock) could hide its self pretty easily. Good Luck!

[hun77777]

i have had hpfp/lpfp issue for about a year now, on and off. i didn't really bother to fix it until the recent track event because, 1) when i initially was going to fix it a year ago, dealership made me pay for inspection since i'm out of warranty, 2) i've been told BMW won't do a thing until i get a code or complete failure of the unit, 3)misfire/long crank happens on random basis and even then it only happens between 3rd to 4th shift on WOT which i rarely do on street.

if you really believe that your issue is something that is related to V4, give shiv a call and discuss with him. i've seen him posting up about misfire from 3rd to 4th so i don't know if that was about you or more of general issues with the tune.

[kanecvl]

I put it in valet on the way the shop and it went limp at about 5500 w.o.t. Some people have probs and some don't I'm just tryin to get to the root of it. What about the people who switched tunes and problems disappeared. Especially if they went jb