[james4321]

Hi guys,
I've got problem with hard (70%-100%) acceleration on 4, 5 and 6 gear.
When I accelerate my 335i (tuned 380HP@550Nm, 2008) my car sometimes hicupping/jerky accelerate. When the gear is higher, 5 or 6, I feel hiccuping more and more. There is No, or I can't feel it at 1, 2 and 3. Little at 4. Hiccuping is only at 3000-4000 rpm.
I'm fighting with this for a year (march 2016).
What I've done:
1. New Spark Plugs
2. New turbos
3. New engine software
4. New air filter
5. Techron added to petrol (4th gear@4000rpm)
6. New tuning
7. New injector at 3rd cylinder, cause at 3rd cyl was worst - after injector replaced, it is better, but not good.
8. Walnut blasting (cleaning of intake valves)
9. New HPFP

Maybe It is not connected, but I've got little rough idle.
There are No errors on the computer (obd II).
I have No idea. I spent a lot of $ to fix this, but nobody can help me.

[james4321]

Nobody? 🙁

[MysticRob]

What mods, plugs, and plug gap? How many miles?
And what index are the injectors? Coded correctly? Banked correctly?
Also wonder if this is transmission related since it would be more noticeable climbing through the gears with higher speeds.
And if you could log these runs and post them up that would be good for the more knowledgeable members to look over.
Boost solenoids been checked and verified functional holding vaccuum?

[james4321]

57000mls
I was changed only one injector.
My car is remaped. Coded coreectly, for sure.
What program I can log my car?
I felt it more at 3,4,5,6 untill I changed injector. Now after replace injector, it is noticeable only at 4,5 and 6 gear. At 4 just a little.

[james4321]

[Aus335iguy]

Originally Posted by james4321

If you're using MHD(android app), use that to log a third gear full throttle pull and post the results through data zap
DO a little search and you'll find what to do - this will be a great help in understanding what your car is doing.

[james4321]

I'm on iOS (iPhone).
My injector at 3rd cyl was index 01. I changed at index 12. Its Ok?

[MysticRob]

Originally Posted by james4321

I'm on iOS (iPhone).
My injector at 3rd cyl was index 01. I changed at index 12. Its Ok?

Not from what BMW says if the rest are all under index 11.

IMPORTANT: Injectors with index 11 and higher have a different calibration and construction than injectors with index 10 and lower. Due to this difference, the injectors with index 11 and higher and injectors with index 10 and lower cannot be mixed on the same engine bank (i.e., cylinders 1-3 or 4-6). Once a bank of injectors is at index 11 or higher, the “bank set replacement” requirement no longer applies. For index 11 injector failures, only replace the failed injector.

No idea what'll happen short/mid/long-term if they're mixed, but I'm sure it's got something to do with the various different lubricants and other internal differences.

Oh, and I've read you should NOT reuse the old couplers, only go with new to eliminate other potential problems.

[Aus335iguy]

Originally Posted by james4321

I'm on iOS (iPhone).
My injector at 3rd cyl was index 01. I changed at index 12. Its Ok?

I would suggest that you buy a cheap tablet or phone for this purpose and buy a decent cable. It'll help you no end.

Also the different index injectors definitely matters and you need to code them up. This will require some software . I'll send you a PM

[james4321]

Ok, well if I replaced injector at 3rd cylinder. Now I have to replace 1st and 2nd?
Or all injectors?

[Gohan335i7]

Upgrade your LOw pressure fuel pump maybe..?..?

[MysticRob]

Originally Posted by james4321

Ok, well if I replaced injector at 3rd cylinder. Now I have to replace 1st and 2nd?
Or all injectors?

For peace of mind and to hopefully eliminate issues completely, I'd personally want them all at index 12. But at least ensure you have all of Bank 1 (that's 1, 2, and 3) updated and coded for Index 11 or above.

[Snypa]

OP...I had a similar issue last week and it was my #1 coilpack. I had to get to 5th/6th gear WOT to reproduce. Also I realized if I eased off, it wouldn't throw a code. So even when its jerking and acting crazy I kept hammering it so it threw a code for me to read.

Something to try.

Thanks

[james4321]

Originally Posted by Snypa

OP...I had a similar issue last week and it was my #1 coilpack. I had to get to 5th/6th gear WOT to reproduce. Also I realized if I eased off, it wouldn't throw a code. So even when its jerking and acting crazy I kept hammering it so it threw a code for me to read.

Something to try.

Thanks

Even It's hard to explain, cause ... when I Replaced injectors on 1st bank (cyl 1.2.3) It is really better. Now misfiring is really rarely. Once it 100 miles. And when I take better fuel (100 octane nitro + shell) It is even more rarely. I dont know what I have to think about it. What I have to do right now.

[SSC Roswell]

Did you ever resolve the problem? If so, what was cure?

[Big Mexican Women]

You're just wasting money on things you don't need yet, such as turbos.

ignition coils. your coil packs. replace them.