[bigsurge]

Hey guys, help please !!! here is the log

https://datazap.me/u/surge1989/log-1...-25&zoom=32-87

The car is a 2007 335i

What's happening is when I'm completely off the throttle and I start to ease back in to it the car jerks and its happening when the afrs go from around 14 to 19, thats what seems to be causing the jerk like clock work. Usually happens more when the cars warmed up vs cold. Also seems to happen when Im on the throttle and I let of, but I dont notice it as much

Any Suggestions would be appreciated, the car pulls fine on wot, idles fine, no codes. When Im trying to cruise normally and I get on the throttle after coasting the afrs go lean from 14 to 19 and it causes a jerk in the drivetrain

Thanks in advance

[Jaronbwall]

Have you reset adaptations lately? That's one issue that causes this. The throttle sensitivity goes out of whack. Also, if you're running an MHD tune make sure it's up to date. I believe it was summer of last year they did some major updates. My car had similar issues which made it impossible to shift smoothly without throttle jerking and we lost burbles which all the teenagers complained about. They revised the tunes, corrected burbles, and a 5 min flash fixed everything.

[bigsurge]

Hey, thanks for the reply

Haven't tried that yet , I was going to clean the vanos solenoids first, then reset throttle and afr adaptations, initially I thought the jerk was coming from the driveline ie driveshaft or something because of how it felt but now looking at the mhd logs, I can see its within the engine

Edit: Also Im on MHD version 10 stage 2+ 93/98, but the issue happens stock and on other maps

[AWD Addict]

Originally Posted by Jaronbwall

Have you reset adaptations lately? That's one issue that causes this. The throttle sensitivity goes out of whack. Also, if you're running an MHD tune make sure it's up to date. I believe it was summer of last year they did major updates. My car had similar issues which made it nearly impossible shift smooth without jerking AND we lost burbles. They revisited the tunes, corrected burbles, and a re-flash fixed the jerking between on/off throttle.

I get a little of the part-throttle jerkiness with my MHD tune.

I guess i need to check for an update.

[Jaronbwall]

Originally Posted by bigsurge

Hey, thanks for the reply

Haven't tried that yet , I was going to clean the vanos solenoids first, then reset throttle and afr adaptations, initially I thought the jerk was coming from the driveline ie driveshaft or something because of how it felt but now looking at the mhd logs, I can see its within the engine

Edit: Also Im on MHD version 10 stage 2+ 93/98, but the issue happens stock and on other maps

Let us know what you find. If you haven't walnut blasted the intake you can also develop these issues. Clogged intake valves affect the AFRs, idle, and throttle response. It was a night and day difference after I got mine cleaned.

[bigsurge]

I've looked at other n54 logs and it looks like when they get back on the gas the afrs go from like 245 or whatever coasting is and gradually go to 18 16 14 and stay around 14 where as mine on the other hand after coasting goes from 14 to 18 and back down to 14 and that 14 to 18 is when I get the jerk

Was gonna do walnut blast anyways but I'll see if it improves anything

[Jaronbwall]

I seems like the DME is searching for the correct AFR or something; almost like it's lagging. I'd also clean the throttle body plate and t-map senor. Maybe it's dirty. This maintenance is basically REQUIRED if you're upgrading or boosting the N54. It's a d**m rolling computer and really frustrating sometimes. Best of luck man.

[BabyJesus87]

Originally Posted by Jaronbwall

I seems like the DME is searching for the correct AFR or something; almost like it's lagging. I'd also clean the throttle body plate and t-map senor. Maybe it's dirty. This maintenance is basically REQUIRED if you're upgrading or boosting the N54. It's a d**m rolling computer and really frustrating sometimes. Best of luck man.

I would do the above and check the charge pipe and make sure that's seated properly or just go ahead and reseat it anyway. Unplug the TB connector and plug it back in. Not a bad idea to try a lil deoxit on the connector terminals too.

[lowrydr310]

I had part throttle jerk on my 335 for a while. I did a walnut blast, new plugs, new coils, none of which fixed anything. I was getting low fuel pressure codes on the low side, so I replaced the LP fuel pump and regulator assembly (both were cracked and leaking a bit of fuel), new LP sensor (that was the cause of the error,) and at same time installed a new charge pipe and cleaned VANOS solenoids. There was no more jerk after that.

It's difficult to narrow it down but my throttle plate was filthy with oil, I think that combined with a possibly leaking o-ring on the old charge pipe connection was causing the issue.

However your AFRs are strange Start with the walnut blast and check all connections at the throttle body/CP.

[bigsurge]

hey boys, just got a better log showing it happening a lot more after resetting adaptions

https://datazap.me/u/surge1989/log-1...4-15&zoom=0-93

basically all the 14 to 20+ afr spikes in the beginning of the log are when the jerk/stutter happens, so when my accelerator pedal goes from 0 to just easing in to it you can see the afrs spike and thats when the Jerks happen

[bigsurge]

Just wanted to update you guys I've found a fix,

I've been playing with the MHD settings and adding a burble fixed the jerking a little bit but it eventually came back, what completely removed it was setting the wastegate rattle fix to 80% its completely gone now and afrs go from 234 to 25 to 19 to 14 instead of 234 19 14 19

I'm thinking the wastegates were causing pressure to build up and when opening the throttle body it would lean out and jerk the car

when I get off throttle its not that smooth but I can modulate that with the gas pedal

[Quick335XI]

Originally Posted by AWD Addict

I get a little of the part-throttle jerkiness with my MHD tune.

me too, always have... always it's when just taking off, part throttle. Never have been able to figure it out or the tuner either.