[gucci335xi]

Alright so i been dealing with this problem for about a month. I have a 08 335xi e90 with ar downpipes, afe intake, jb4. So i have been having it where i would just be driving it down the highway normal and once in a while if i get on it, the car starts to cut out or act like a fullpump going bad issue. Or possibly missfire. I had put it on map 7 with 93 gas and octane booster. It happened on that map and does it on all theres.

I got a smoke test done and have no leaks. I just got spark plugs and what going to check the ones in the car now.

Anyone with helpful advise pleaseee helppopp!!!!!!!!

[JamesM3M5]

First off, welcome to E90post.

You have installed new plugs or not yet? How many miles on the car? Got a name?

You can also search for "misfire" and read through the typical fixes. 1) install new plugs. 2) move coils, see whether the misfire moves with the coil. 3) possible injector(s), excessive carbon buildup, bad PCV allowing a lot of extra oil into the intake, bad O2 sensors, etc.

[marv85]

+1, but more importantly map7 is very aggressive to 93+octane booster buddy! You need 100 octane fuel for that one.

Are you saying since it happened on map7, it now happens on all maps?

[cn555ic]

Need to read codes first and foremost

[Jeff@TopGearSolutions]

If you have over 25K miles on the current spark plugs try changing them. Without codes we can't offer much more advice though.

[marv85]

guys, am I the only who finds it wrong to run Map7 (16.5 PSI, now 19PSI if he has new software), on stock timing with 93+octane booster?

[WilliamS]

Get off map 7 go to map 5. Push DTC once so light is on in the dash, go full power a few times. Odds are JB4 is pulling power becuase your no on race fuel, as well if its surging on power your getting wheel spin and the car itself is pulling power.

[marv85]

^ My thought exactly, except it's not the JB4 pulling power, it's the DME

JB4 is trying to boost 16.5 on stock timing when your octane doesn't permit it...

[gucci335xi]

Car has about 28000 miles on it. I am not showing any codes. And its doing it on all maps now. Has done it with the jb4 disabled as well but very few times

[marv85]

I find it weird that you have no codes... Do the plugs and see if that fixes it

[King mode]

I friend of mine has had trouble with the power "breaking up" above 4000 rpms with his jb4. Its on and off though. I would do new plugs and if that doesn't help, check coils.

[boostaholic786]

I have a buddy on stock turbos still doing this exact same thing but on map 5 with 4 gallons E85/ rest 93 octane. Def check your codes because nothing can be of help without some sort of evidence. If your getting a vibration or hesitation, You probably need new plugs, coil packs, or even maybe bad injectors (see if your car hasnt got injectors installed yet and try and go thru BMW....take your JB4 off just to be safe) If your good with the JB4, try and get a log and send it to Terry or Burger Motorsports and see what they say. Also, map 7 is a RACE GAS map.. 93 with octane booster isnt going to make it to a 100 octane MINIMUM.. I personally havent tried it and dont suggest others to unless they want to have issues, like you are experiencing

[boostaholic786]

Terry is offering a DME reflash done thru Burger Motorsports on COBB tuning DME flash. if your running a strong, consistent E85 mix with 93 octane, you should def try and go this route Car pulls and pulls very nicely without having hiccups or "surges" of power

[Redrkt503]

Mine was same situation, turned out to be crank sensor

[gucci335xi]

Alright im gunna try the plugs i just picked some up see what happens. What if my stock ones are looking good what should i do then?

[marv85]

They are cheap, I would change them anyway.

[JamesM3M5]

You can't go by "look". At 25k miles on a tune, it is definitely time to change spark plugs. The electrodes wear down and make it harder to fire the spark. Rounded electrodes bleed electric charge, while flat elctrodes build charge then suddenly spark. Combine that with increased boost, and it is even harder to fire that spark. Something about relative permittivity of the fuel/air mix in the cylinder, I dunno, I'm just talking out of my ass.

[gboop]

Originally Posted by gucci335xi

Alright im gunna try the plugs i just picked some up see what happens. What if my stock ones are looking good what should i do then?

Recently I had similar symptoms when it got colder.
Started with an occasional sputter/pause, then finally got a misfire code on cylinder #6.
Changed all my plugs (had 1.5 years on them) and swapped cyl #6 coil to cyl #1 just in case.

Problem went away for a week and then it came back.
Single sputter, but no codes, since I instinctively let off whenever I felt something.
The DME needs to register multiple consecutive misfires in order to throw a code,
so I did a long 5th gear pull and finally got multiple misfires that registered a code for cyl #1 this time.

So for me it ended up being the coil, which I replaced the next day and have been fine so far. YMMV.

[gucci335xi]

I just did the plugs and its doing it a little bit still. Not as bad but still does it. Also the car just feels slower. Just doesn't feel like its got the power like it used to.


This problems driving me nutzz haha!!! What should i do next i feel like im shooting in the dark!!

[cn555ic]

I just can't believe there are no codes. There has to be some type of code if the car cuts of in power when going WOT

[gucci335xi]

Alright i guess logging is gunna for sure? Tell me whats going on with the car right?

Thing is how do i do this logging ive never done or seen it?

[Quebequer]

Originally Posted by gucci335xi

Alright i guess logging is gunna for sure? Tell me whats going on with the car right?

Thing is how do i do this logging ive never done or seen it?

You definetely need to log. Just read the readmefirst doc you get when you download JB4 interface. Open your interface, take a log, and post it here. You should send one to Terry from BMS too.