Heavy Misfire under boost

[AZ135i]

So i recently installed cobb ap v3 and running stage 2+ sport. I am getting some sort of limiter or bad misfire under boost around 4-5k rpm. I bought new plugs and regapped to .22 and went and some pulls today and it always seems to misfire after 16-17 psi mid 3rd gear and 4th gear. Any ideas? Mods are ER Charge pipe, bms dp, bms intake. I have 2011 n55 dct 135i. I did some data logs and nothing shows up there. I have only got engine misfire codes once while it was doing this. It will misfire just about everypull once car is warmed up. Cobbs website says stage 2+ sport only boosts to 16 psi, but I am seeing 18 and 19psi sometimes. Am i running out of fuel? My afrs are 10.8- 11.1 through all my data logs.

[ShocknAwe]

What fuel are you using? Octane? Any E85? What was the code you pulled? Was it before or after new plugs? Did you buy BMW plugs?

First thing I think is that you need higher octane or maybe just more fuel, at what PSI does the misfire show up?

[AZ135i]

Originally Posted by ShocknAwe

What fuel are you using? Octane? Any E85? What was the code you pulled? Was it before or after new plugs? Did you buy BMW plugs?

First thing I think is that you need higher octane or maybe just more fuel, at what PSI does the misfire show up?

91 with a few gallons of e85. Sometimes 15psi others 18psi it's all over the place and it does it around 4k-5k

[AZ135i]

I'm running sport for 91 octane and only go to shell stations

[ShocknAwe]

Can you get 93?

[AZ135i]

Originally Posted by ShocknAwe

Can you get 93?

No I'm in Arizona... 91/e85/100. I'm not daily driving on 100 octane lol

[tehron]

bad ignition coils perhaps?

[ShocknAwe]

For the high boost levels your car seems to want to hit, assuming your spark system is healthy, since you have 91 and already tinker with e85, I'd try upping the ethanol mixture to increase effective octane and see if it stabilizes. Not an expert on that though, nearest e85 station here is 15 miles from me so I don't run it much at all.

[edisapimp]

Do you have an intercooler?

[ChrisCote]

Take a log

[AZ135i]

Originally Posted by edisapimp

Do you have an intercooler?

Yes sort of it's in the mail :-/

[AZ135i]

Originally Posted by ChrisCote

Take a log

Im going to do some logs tonight and see what happens... I do have a few logs while it was doing this and nothing looked out of the norm...

[AZ135i]

http://www.datazap.me/u/az135i/data-log-26

http://www.datazap.me/u/az135i/data-...log=0&data=4-5

[Boosted_N54]

how are you running STAGE 2+ if you don't have FMIC and DOWN PIPES ?

it is required those two to run stage2+

[AZ135i]

I have down pipes and my intercooler will be here soon. I asked what map I should run with the mods I had and everyone said map stage 2.

[houtan]

Stage 2 and stage 2+ are different. Sounds like you are running stage 2+ which requires an intercooler. Not in the mail, it has to be on your car. So I would switch to stage 2 sport map first and see how your car runs.

Having said that, if your car still does the same thing, I would put your stock intake on and see if that makes a difference. I was fbo minus a bms intake and my car ran awesome on stage 2+ sport. Added bms intake and my car did the same thing you described, so I took it off. Have done 91, e30, and e50 ptf etunes since and car still runs awesome with stock intake (afe drop in). I am going to try the intake again once my etunes are finalized and see how the car runs.

One thing to look at in your logs is throttle closures around the rpm you are experiencing the issue. I believe it's column b and c in the log. See if the actual tps is way below the requested tps when you're requested is at 99% (full throttle)

[AZ135i]

Originally Posted by houtan

Stage 2 and stage 2+ are different. Sounds like you are running stage 2+ which requires an intercooler. Not in the mail, it has to be on your car. So I would switch to stage 2 sport map first and see how your car runs.

Having said that, if your car still does the same thing, I would put your stock intake on and see if that makes a difference. I was fbo minus a bms intake and my car ran awesome on stage 2+ sport. Added bms intake and my car did the same thing you described, so I took it off. Have done 91, e30, and e50 ptf etunes since and car still runs awesome with stock intake (afe drop in). I am going to try the intake again once my etunes are finalized and see how the car runs.

One thing to look at in your logs is throttle closures around the rpm you are experiencing the issue. I believe it's column b and c in the log. See if the actual tps is way below the requested tps when you're requested is at 99% (full throttle)

I am running stage 2 sport... I'll try a stage 1 map an work my way up until i see when it happens again. I get an o2 sensor code daily but I have a bms cat less downpipe would that be a factor?

[houtan]

Your original post says you are running 2+.

Not sure about the O2, but my gut is telling me it's not the issue since you are catless and expect to see that code.

Are you seeing throttle closures in your logs?

[AZ135i]

Originally Posted by houtan

Your original post says you are running 2+.

Not sure about the O2, but my gut is telling me it's not the issue since you are catless and expect to see that code.

Are you seeing throttle closures in your logs?

if you look at my early logs everything seemed good... I was running lower boost levels for whatever reason, then bam it started boosting 18-19 out of no where and then the problems started.

yes stage 2+ sport. No throttle closures... logs 28-35 are all doing the break up... you can see the big drops followed by steep peaks, thats where it was missing so bad or breaking up that i had to get out of it and hit the gas again...

http://datazap.me/u/az135i

[ShocknAwe]

Looking at the last log (35), under WOT your boost starts climbing up to ~18psi and then you start to pull timing on 4 cylinders. You're pulling timing on 3 cylinders from about 15psi at WOT. Someone correct me if I'm mistaken but at WOT the ideal is zero correction and certainly no more than 3 cylinders.

What map was that on? Stage 2+ sport? If so have you run a log on any map not requiring an Intercooler?

[AZ135i]

Originally Posted by ShocknAwe

Looking at the last log (35), under WOT your boost starts climbing up to ~18psi and then you start to pull timing on 4 cylinders. You're pulling timing on 3 cylinders from about 15psi at WOT. Someone correct me if I'm mistaken but at WOT the ideal is zero correction and certainly no more than 3 cylinders.

What map was that on? Stage 2+ sport? If so have you run a log on any map not requiring an Intercooler?

I'll switch to a lower map and see what happens. I am off next 4 days.

[AZ135i]

Added e95 and stock Intake car runs great thanks houton