Z4 28i full throttle high rpm misfire

Kiashi123

Member
So I have a question/problem about my bmw z4 28i 2012 automatic.

i just bought it. Had 95k km. I have a serious problem! Sometimes when i full throttle to red line it misfires! Car goes into safety mode. On scan it says misfire. Sometimes on cylinder 1 sometimes cylinder2 sometimes cylinder 4. What could be the problem?

i changed spark plugs and Coils..

did anyone have the same problem and fixed it? Only happens sometimes and at full throttle near redline0408BDE1-57F9-44E3-92BC-B72CF6E62252.jpeg
 
Thanks for the reply… how do i check fuel regulator and pump? Will have to get it checked by some good mechanic.. went to some private mechanics.. dont seem to k ow where is the problem.. they just want me to order everything and see if it works..
 
Could be an issue with the HPFP..your car is an earlier one and being a 28i, is it mapped?..the first generation fuel pump could be the issue..there is a later version..can you do data logging ?

Something like Protool is useful..

Other things that could go wrong is the crank sensors…

FWIW that’s best guess..data logging of the HPFP would show it sagging if that’s an issue..
 
Kiashi123 said:
It is mapped. To 280hp. I deleted the map but it still misfired. So i maped it back. I cant to data logging

Well I’ve had a similar fault..HPFP was certainly failing …

You need to get a tool like Protool to do analysis and data logging..

Your garage in part is right, without sophisticated tools parts substitution becomes the only strategy..
 
Thanks man! Hopefully i fix the problem. Love the car but cant enjoy it because of the damn misfire.. its frustrating.. has been almost a month now..
 
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