N54 335i Throttle loss


May 14, 2018
2009 E92 335i DCT
Hi all.
I am having a bit of a weird issue with my 2009 E92 335i N54 DCT that i cannot for the life of me get to the bottom of.

it started 2 weeks ago.
When i am going WOT, and reach the higher RPM, i get very sudden Throttle Closure. so bad in fact that it feels like my engine is going to uproot itself out of the mounts.
I am not getting any Error Codes, i am not getting pushed to map 4 for safety.

I have the following mods:
JB4 (latest Firmware 32//14
BMS Pump BEF (latest revision 02/07/19)
Stage 2 Hybrid Turbos
2"OEM Location silicone inlets
6"AMS Intercooler
Charge Pipe with Tial style BOV
WMI with CM10 nozzle
N20 Sensor

the issue im having happens in all JB4 Maps, in all Gears, and regardless of whether i am using my Meth or not.

I have done the following to try troubleshoot.

Remove N20 Sensor and replace stock TMAP
Revert to the previous JB4 Firmware 32//12
Reset all adaptions in JB4
Reset Throttle settings using the 30sec throttle method
Unplugged the Throttle Body and repluggeed it in to check correct seating.

With all the above done, the issue persists.
here is a log as of last night attached.

my mind is now looking at the following causes of the issue:
Throttle Body faulty
Alternator faulty (possibly effecting voltage to Throttle Body?)
DCI filters maybe dirty

Another option, i heard that the DCT box has torque limits, my question here is, what will happen if im reaching or reached the Torque limit, will it cut power, or give me an error?
i am not sure what power i am running, but i have tested the car on JB4 Map 0 and Map 4 which is low boost of 8psi, and i am still having the problem, so i assume this rules out my Gearbox being an issue.

My fuel Pump values in JB4 logs are correct and seem above the required limit of 10 (HPFP) and 60 (LPFP).

I am now stumped.
thank you in advance.



  • 2019-05-14 20_38_05_Gear-3_Map-2.csv
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