[335stick]

i just got my jb4 installed, now the car jerks mostly 2nd gear and up, feels like the boost is going back and forth.
My foot is steady on the gas, speed is climbing but notice the fluctuation on the fuel gauge in the video ,I'm using the boost on fuel feature.
what would cause this?

[mike@x-ph.com]

Post a datalog

[335NJ]

Get a log posted, and also what map do you have it set at?

[335stick]

I will when I get a chance. I'm completely stock. Map5

[335NJ]

Originally Posted by 335stick

I will when I get a chance. I'm completely stock. Map5

Map 5 is fine. I'd pull the ECU cover and make sure all the connections are seated properly just as a precaution, don't forget to let the car sit for 10 minutes to let the ECU go to sleep. Maybe do a full re-install to be sure, then button the cover up and fire up the car.

Does it idle ok?

[335stick]

Idles perfect boost fluctuates at half throttle

[335NJ]

When you installed the JB4, did you do anything else? I'm wondering if you have a boost leak or something. But, if it was this significant, you'd be getting a code of some sort.

Did you buy the unit second hand, or new?

[335stick]

I bought the jb4 used. I only did the jb4 itself. No codes.
I have brand new plugs and coil ready to be installed but I don't think that would be the issue.
Never hooked it up to the laptop so I'm reading and learning on how to do a datalog

[MuNkY6913]

You would get a lot more help if you posted the .csv file in a thread in the support section of N54tech forums. Once you get that figured out. That's the place you're likely to get the quickest help.

[335NJ]

Originally Posted by 335stick

I bought the jb4 used. I only did the jb4 itself. No codes.
I have brand new plugs and coil ready to be installed but I don't think that would be the issue.
Never hooked it up to the laptop so I'm reading and learning on how to do a datalog

Also, download and install the latest firmware update. Is the JB4 you bought the G5 ISO unit? Some surging issues, like this have been solved by firmware in the past. Also, maybe the old owner had some custom settings saved on the unit?

Read through this: http://www.n54tech.com/forums/showthread.php?t=10605

Follow the firmware FAQ, datalogging FAQ, etc.

[335stick]

When doing data logging. Does the the laptop have to be to connected while I'm doing the runs?

[335NJ]

Originally Posted by 335stick

When doing data logging. Does the the laptop have to be to connected while I'm doing the runs?

Yes, download JB4 interface from N54Tech, follow instructions on setup, then click File>Connect & at the top click Data Logging>Stop & Display after a few seconds, then when you're ready, click Data Logging>Start and get some short pulls logged. That's how I do it, but read the thread I linked above. The logs don't have to be WOT especially since you're having an issue.

In the future though, once this is resolved, you want to log an entire range of 3rd gear, and a bit of 4th to best display everything for review.

[Mike@N54Tuning.com]

Originally Posted by 335stick

i just got my jb4 installed, now the car jerks mostly 2nd gear and up, feels like the boost is going back and forth.
My foot is steady on the gas, speed is climbing but notice the fluctuation on the fuel gauge in the video ,I'm using the boost on fuel feature.
what would cause this?

Any codes? Datalog would help.

Mike

[335stick]

Just took the cover off the jb4 box and noticed that the diodes are still connected so I guess it's not an ISO board.
Changed plugs and coils.
The car has been holding good boost for the past couple days. I notice a jump in boost at partial throttle.
Data logs coming later today and might cut the diodes out and do an ISO conversion and firmware update. I hope this will help.
Btw found a code that was related to the ecu cooling fan. I reseated the fuse.
I took the car for a long drive and now will plug the laptop and c if any codes came up.

[335stick]

Codes
2f71
2d2e

[335NJ]

27F1 is the E-Box fan #13http://www.realoem.com/bmw/showparts...96&hg=12&fg=35
Check all connections are properly seated first/wiring.

2D2E- Angle of throttle valve
I'd check chargepipe/DV connections, and vacuum lines. An N54Tech thread has Terry saying disregard it's a common code from JB4, something about the lagfix.

upload .csv file to datazap.me

[335stick]

Car wants to full boost at 2000-3000 rpm

[335NJ]

Originally Posted by 335stick

Car wants to full boost at 2000-3000 rpm

That might be the 2D2E code talking, i'm not sure what's all involved, but maybe the car thinks you're giving it more throttle than you really are?

Try to get a log of regular driving, no wide open throttle, just cruising through gears for a minute or two.

[Jeff@TopGearSolutions]

Try to get your datalogs onto datazap.me

[335stick]

http://datazap.me/u/335stick/jb4-1?log=0&data=1-4

[335NJ]

Originally Posted by 335stick

http://datazap.me/u/335stick/jb4-1?log=0&data=1-4

The beginning of that first pull, your throttle position is all over, spiking up and down. I'm thinking that 2D2E code is the culprit there.

Boost is spiking up and down as well, along with others parameters. I'd like to see some of the more experienced log readers chime in on that log.

It also shows meth pegged at 100, across the board, when on pump gas according to the logging parameters FAQ it should be around 40, although again, i'm not 100% that's an accurate analysis.

http://www.n54tech.com/forums/showthread.php?t=21269

[GetSomeE92]

From the pic you posted it looks like you are targeting around 8 psi but are way over shooting and hitting 14 psi. Then you're getting a massive throttle closure as a result. If I were you, I would go to the settings page and make sure you have the correct selection in the drop down box for the JB4 board and firmware you are running. If you can, try to restore the default settings (not sure if this feature was removed from the interface or not, though).

Definitely create a thread in the support section of N54tech.com as you will get more help over there.