Engine stutter/jerk/hiccup after JB4 install

[yaga11]

Hello all, this is my first thread on this forum.

I recently purchased a CPO 2011 135i. The car as been great and it was exactly what I wanted in my next car.

I put on a JB4 stg 2 Friday and starting having issues with the ride randomly jerking. Its a solid quick hesitation and it happens randomly. Sometimes I can drive for 10-20 minutes with no problem. Other times it happens multiple times in a few minutes. I have not experienced any hesitation when going WOT, only when cruising along. The issue is also apparent in all the maps I have tried (0, 1 and 5). While driving tonight, I noticed the lights flickered along with the hesitation.

Troubleshooting steps so far
-Checked connections
-reinstalled firmware
-upgraded to ISO and installed latest HEX firmware
-set 'lagfix' to 0
-triple checked connections (cleaned the CAN wires thoroughly)
-reseated the power line

The board physically looks good. The JB4 is brand new and has not been on another car before mine. I have not uninstalled the JB4 yet to check to see if this issue coincidentally started when I installed the JB4. I am hoping that someone on here has had similar issues and knows a quick fix.

[edisapimp]

codes?

[Mike@N54Tuning.com]

If running N55 BETA ISO firmware maybe you just set default waste gate position too high. Lower values are smoother. Best bet is to post a log to the N54tech support section for assistance. No one here will be able to help.

Mike

[yaga11]

No CEL and no codes at this time, just checked.

I did initially get 2c90 when I first installed the JB4. From what I understand this is a common 'tuner' code.

Thanks Mike, I will post up on N54tech

[jsphczz]

I have the exact setup and issue you are reporting. I thought that putting the jb4 into map 0 would disable it and in turn prevent the stutter from happening but it still occurs. I see you did not have any luck on the n54tech forums either so please let me know if you have any updates on this. Thanks.

[Miko226]

Check plugs and coils also if you have not done a carbon cleaning

[AB M2C]

The JB4 piggybacks on the ECU. Whats most likely happening is the ECU is learning different AFR's under different throttle conditions and loads. Give it 500 miles of different kinds of driving (some highway cruising, some 2-4th WOT pulls and see if it goes away). Chances are at some points right now you're running a little lean and to prevent detonation the ECU is cutting power.

[yaga11]

Thanks for the reply OneKid, Terry ended up sending me the Gen 1 JB4 Stg 2 board and that appears to have resolved the hesitation. He believed the issue was with the revised ground connection on the Gen 2 board.

Everything is running smoothly, except for moments when there is a large delay before I build boost when running Map 0. Maps 1 and 5 build boost very quickly. I currently have DWP set at 50, I may try 80 to see if it helps out.

[excesss]

Yaga I'm having the exact same issue with my JB4. It's only at cruising speed as well. A hiccup is a good word for it. I'm also having much more lag than stock. It's almost as though the car has two stages, it pulls then once it gets revving more it pulls even harder. It's nothing like it was stock. I've been talking to tech support but no resolve this far. Car is also making a clucking noise that started immediately after the install. Almost tempted to go back stock and say f it.

[yaga11]

I would double check your ground connection.
Also do you know if you have the Rev 1 or Rev 2 board?
Rev 1 or 2 should be printed on top of the board

[excesss]

I'm going to check the board version later after work. BMS has asked for pictures of both sides of the board as well.

I've triple checked all connections including the ground. A painted surface better yet a strut mount bolt is a less than ideal spot for a ground so I'm thinking about finding a better spot to ground.

I've narrowed the clucking noise to my throttle body so I've made some headway as to the source. Just need to figure out why now. It started immediately after the install so its more than likely related to the install/new parts.

[Mike@N54Tuning.com]

Originally Posted by yaga11

Thanks for the reply OneKid, Terry ended up sending me the Gen 1 JB4 Stg 2 board and that appears to have resolved the hesitation. He believed the issue was with the revised ground connection on the Gen 2 board.

Everything is running smoothly, except for moments when there is a large delay before I build boost when running Map 0. Maps 1 and 5 build boost very quickly. I currently have DWP set at 50, I may try 80 to see if it helps out.

Yes it turns out the E series N55 require the Gen1 board. They are updating the Gen2 boards in stock to include the extra ground. If anyone has a random stutter that is the issue and BMS will swap the board out for you.

Map 0 when running N55 ISO BETA runs zero wastegate or around 4psi. It's not meant to be driven on. When running normal integrated it runs your factory boost target and can be driven on normally.

Mike

[yaga11]

Ahhhh you are the man Mike!
Thanks, and can you point me in the right direction to understand the changes made in the ISO firmware updates? I am not able to find anything using the googles.

[Mike@N54Tuning.com]

Originally Posted by yaga11

Ahhhh you are the man Mike!
Thanks, and can you point me in the right direction to understand the changes made in the ISO firmware updates? I am not able to find anything using the googles.

The JB4 N55 ISO BETA thread along with any and all other info BMS product related is on n54tech.

Mike