[BullowM3]

Who here has a 335is with the jb4 chip. Any problems? I have noticed the downshifting there is about a second lag before the engine kicks in. And i have also had several misfires when attempting to floor it. About 40% of the time it downshifts and i floor it the accelerations choppy and the car wont accelerate because its misfiring and i throw an SES. Please note this car has 5000 miles on it so i highly doubt its because i need new spark plugs or coil pack. Any advice or help would be appreciated

[BQTuning]

BEAR-AvHistory is the perfect person to answer your concerns. However what I do know is that on the JB4 there is a 335iS "specific" map that you should be using.

[BEAR-AvHistory]

Maybe not the best person but I have done a lot of software testing, swapping logs & implementing suggestions from Terry & am running the ISO system. Bottom line for the most accurate answer email Terry & send him a log with the problem taking place.

That being said a few just be sure things. What JB4 version do you have, what interface date & what firmware version? Is the JB4 firmware running the 335is specific Maps? What fuel are you using?

Few thing I did about hitting WOT. I blocked the pedal so I don't hit the WOT kick-down switch but still get 100% open throttle. When a situation arises that I have to go to WOT I drive the car like a stick shift & manually shift. Usually a 2 gear down shift will avoid any hesistaion. The JB4 also has a built in "LAG-FIX" that you can dial in to greatly reduce or eliminate the problem.

The thing you really need to do after checking that the basic install & that the software is current is to create some logs of the problem. Will try to answer any questions about the JB4 on the IS that I can.

[BullowM3]

I have the jb4 g5 and I usually run map 1 or map 5. what are the specific 335is maps? And i will try to get logs of it thank you very much

[BullowM3]

I run just 93 octane

[BEAR-AvHistory]

Do you have interface 12/14? What firmware are you using? Is the G setup for ISO? 93 should run any of the maps 1, 5 or 6. I use Map6. 5 is an all round good map because its a learning map. Problem is it learns on 3rd & 4th gear pulls at WOT.

Since you are having an issue with misfires stay with map 1 till it gets worked o

EDIT: forgot to ask do you get clean runs on map 0?

[BullowM3]

Map 0 runs fine. I have ar catless downpipes but I had the WOT problem before I had those put in. Im not sure what interface I have I know my friend updated the chip when I had it put in a few months ago. Its obviously something with the dct because i had an 09 335i 6at and i didnt have any of these same problems

[BEAR-AvHistory]

The JB4 does not effect the 7DCT its on its own system. You most likely have one of the early beta firmware versions or early interface both of which have been improved.

Hook the JB4 up to your laptop & get the versions off the interface user adjustment page.

If you are running G5 ISO you need interface 12/14 & firmware G5_ISO_15C.hex If you are running G5 without ISO you need interface 12/14 & firmware G5_100112.hex

Be sure not use the ISO firmware version if you are not running an ISO board.