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Ali Aljadir Ali Aljadir is offline
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Join Date: Jun 2021
Car: 2009 BMW Z4 sDrive35i
Exclamation JB4 in my Z4 sdrive35i having issues PLEASE HELP! - 06-17-2021, 04:24 AM

Hello, I am new here. very new. ok enough about me. ok, I installed the JB4 on my z4 last week and im having problems with my cars acceleration and an engine reduced power warning on my idrive screen. So when im in sport+ mode and even in regular mode where i push my car a little bit hard it jerks from gear to gear where it feels like its about to bog out. Before i put the jb4 in I could drive it very aggressively without a problem, but now I cant even come close to driving it as hard as i would before putting in the jb4. Im not sure if I mixed up the position of the wiring slots on the ecu or what. I dont want to try and reverse the wiring slots cus i dont know if Ill fry it. It makes me feel like i wish I never put in the jb4. It does this on any map i set it to. also does it on map 0. Ive even completely taken the JB4 completely out my car and still does the same thing. Please help. This is very frustrating and i dont know what to do. I dont want to fry my ecu. let me know if you have had similar problems. Also forgot to mention but i bought my jb4 second hand from some one who had a manual 335i n54. dont think thats the problem, cus like i said even when I take it out i have the same problem. any input from the JB4 veterans would be appreciated.
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Steve @ BMS/Fuel-It! Steve @ BMS/Fuel-It! is offline
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Default 06-17-2021, 10:42 AM


You need to post a log and install pictures in the correct forum for assistance.

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