[Stranger2k1]

Hello from mid-european austria,


I hope that someone in this speclialists forum can help me with my problem.
I own a 2007 model (built 12/2006) 335i, manual transmission. I had no problems with stock software at all. After chiptuning (to about 380hp, acc to the tuner), the engine is kind of “jerking” through the whole rpm range, when I put the pedal to the metal. It feels like somebody is lifting the pedal a little bit, then pushing it down again and so on. Between 4.000 and 5.000 rpm, there is a well noticeable performance loss, you can really feel that he doesn’t like it… but above 5.000rpm it is fine again.

Ok, now that’s the problem, but what is the cause? My tuner is turning the easy way out by saying “my software is good, there has to be something with the car…” – and he even names the fuel pump (not the high pressure railpump, but the one on the tank) as the definite cause for the problem.

I really don’t know what to think or do now. First of all, I restored the stock engine software because I think it could harm the engine if I drive around with this malfunction.

I can definitely say that the gasoline is not to blame, because I only put 100 octane in the car.
And as I said, with standard software, everything works fine. No hardware modifications have been done so far.


I hope that maybe somebody here already had the same problem and found a solution to it.

Thanks in advance
René

[N54_Fan]

Originally Posted by Stranger2k1

Hello from mid-european austria,


I hope that someone in this speclialists forum can help me with my problem.
I own a 2007 model (built 12/2006) 335i, manual transmission. I had no problems with stock software at all. After chiptuning (to about 380hp, acc to the tuner), the engine is kind of “jerking” through the whole rpm range, when I put the pedal to the metal. It feels like somebody is lifting the pedal a little bit, then pushing it down again and so on. Between 4.000 and 5.000 rpm, there is a well noticeable performance loss, you can really feel that he doesn’t like it… but above 5.000rpm it is fine again.

Ok, now that’s the problem, but what is the cause? My tuner is turning the easy way out by saying “my software is good, there has to be something with the car…” – and he even names the fuel pump (not the high pressure railpump, but the one on the tank) as the definite cause for the problem.

I really don’t know what to think or do now. First of all, I restored the stock engine software because I think it could harm the engine if I drive around with this malfunction.

I can definitely say that the gasoline is not to blame, because I only put 100 octane in the car.
And as I said, with standard software, everything works fine. No hardware modifications have been done so far.


I hope that maybe somebody here already had the same problem and found a solution to it.

Thanks in advance
René

Specifics on what "software tune" you were running would help others chime in. Is it a piggy back? or ECU flash? and who makes it? Was it custom for you by that "tuner" or did you go with one of the 4-5 frequently mentioned ones on this forum?

[enrita]

Do you get any codes? Half engine light? Seems from your description the car is having constant throttle closure events probably due from bad tuning ... Get the software fix by your tuner or get your car flashed back to stock and change tune.

[Stranger2k1]

thanks for your quick answers.

it was done by a local tuner here in austria. i am not a specialist when it comes to software mods, but from the time it took him to do the modding (~45 minutes), i would say that it is not really a custom software for MY engine, it looks like a standard file to me.

what is a "piggy back"? some tuning box? if yes, then i can say "no, it wasnt". the ECU has been flashed with the new software, this i can tell for sure.

the engine light went on once, but only in idle. after turning the engine off and on again, the engine light was off and never appeared again.


i DID flash it back to stock. but tuner says it is not his fault, because he already did a lot of 335i's, without problems. he states that it is quite sure that the fuel pump is to blame. but i dont want to spend another 300-400€ for nothing...

[enrita]

if your fuel pump is on his way out than you would get codes that point to it and limp modes running stock as well.
I would advise you NOT to go to that tuner again and grab a piggyback like the Procede V5 .Flashing the N54 is a tricky business. Not all flash are well done and our DME has som many different versions that maybe that particular flash doesnt work at all with your version.

[Stranger2k1]

i can read it via I*PA, and i had 2 error codes in it:

10887 and 12544. there is no description given in the program, so i cannot tell if it has something to do with the fuel pump or not.

the problem is that the tuner doesnt want to give me my money back, as he has the oppinion that his software is not faulty.....

[marv85]

^ +1 I agree. I think you should go with something tested in the community.

[N54_Fan]

Originally Posted by Stranger2k1

i can read it via I*PA, and i had 2 error codes in it:

10887 and 12544. there is no description given in the program, so i cannot tell if it has something to do with the fuel pump or not.

the problem is that the tuner doesnt want to give me my money back, as he has the oppinion that his software is not faulty.....

10887 = Outlet-VANOS variable cam control test

12544 = boost-pressure control, deactivation The no boost limp mode caused by another fault code

Sounds like your car had the ECU flashed. I would ask your "tuner" who makes the ECU Flash and then DO NOT go there again. Something is fishy with him. If your car works fine stock then I would research the type of "tune" you want on your car before you trust anyone. There are about 4-5 different ones that are commonly talked about on this forum. Do a "search" here as it is too lengthy to give you a breakdown of the tunes. I believe there is a "sticky" on the topic as well.

[Stranger2k1]

hi guys,

again, thanks so far for your assistance. at the moment, i am waiting for the new spark plugs (bosch high power OEM) to arrive. first of all, i will change the plugs, before i put in a new fuel pump.

the tuner itself is still saying that his software mod works fine on a number of 335i's he already did and he remains on his point of view that there has to be something wrong with my car.


well, i will keep you updated for sure. hope that the plugs arrive tomorrow, but thanks to the easter-weekend, i am not too optimistic about that...

[tscdennab]

I would really advise you to go with a known-brand software. Even european ones, but choose a known brand, not custom software. The N54 flashes cannot be mastered easily.