DIY Data Log for FBO N54 (Throttle Cutting/Shuddering)

ClaytonT

Lurker
Jan 25, 2021
16
2
0
Hi guys

Hope everyone staying safe. This is a data log showing the hesitation and or loss of power under WOT that I’ve been experiencing lately. It feels like it’s on the verge of going into limp mode but then recovers and the boost will then keep building right up and through the gear change into fourth.

Would really appreciate any advice, plan to do spark plugs to eliminate but had already changed them 10-15 thou km back. I saw the low boost too, surely the tune wouldn’t have the car on 12PSI?

FBO
Stage One tune
E92 335i N54

Thanks!

Yk6Z_sxrdXO0BQ86uFu-81H67JdBDPvk

 

KClemente

Corporal
Nov 26, 2019
223
103
0
Ride
E90 335i
What's it tuned with? Bimmerlabs? External flasher? Reason why I'm asking is because MHD doesn't know what file is flashed on the bottom right.

Anyway. You're running some seriously dangerous lambda judging by the fact that your afr monitor is showing 20-22, and your STFT's are both maxed out at 34%. I'd highly advise a re-tune or a diagnosis of some underlying issue.

Other than the seriously dangerous fueling issue, your boost control could use a little work and isn't great but isn't awful compared to your STFT's.
 
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ClaytonT

Lurker
Jan 25, 2021
16
2
0
What's it tuned with? Bimmerlabs? External flasher? Reason why I'm asking is because MHD doesn't know what file is flashed on the bottom right.

Anyway. You're running some seriously dangerous lambda judging by the fact that your afr monitor is showing 20-22, and your STFT's are both maxed out at 34%. I'd highly advise a re-tune or a diagnosis of some underlying issue.

Other than the seriously dangerous fueling issue, your boost control could use a little work and isn't great but isn't awful compared to your STFT's.
Thanks for the response, how do you mean dangerous? It does overfuel and backfires pretty wicked sometimes. It was tuned by a third party locally, with an external flasher and I use MHD to monitor, would you recommend an off the shelf tune from MHD? I have only purchased the car recently so don’t have any information on the tune
 

KClemente

Corporal
Nov 26, 2019
223
103
0
Ride
E90 335i
Yeah if you like your car, get rid of that tune asap. I mean dangerous by the fact that your car is leaning out and not getting enough fuel which may lead to a cracked piston sooner or later.

If you're FBO you might aswell go with MHD stage 2+ or a custom tune from someone else.
 
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ClaytonT

Lurker
Jan 25, 2021
16
2
0
Yeah if you like your car, get rid of that tune asap. I mean dangerous by the fact that your car is leaning out and not getting enough fuel which may lead to a cracked piston sooner or later.

If you're FBO you might aswell go with MHD stage 2+ or a custom tune from someone else.

I’ve just changed the tune to mhd stage two and reset all adaptions it’s way way better now, here’s a data log to it. Are there any issues you can see ? Thanks !

 

ClaytonT

Lurker
Jan 25, 2021
16
2
0
Cheers yeah it’s much better! a completely different car for sure. do you think the timing corrections are a concern ? Running the 98RON map, you think maybe adding 100RON would improve it at all
 

carabuser

Lieutenant
Oct 2, 2019
549
1
410
0
UK
Ride
Z4 35i & 335i
Big improvement over the mystery map. I would try the stage 2+ 91 map. You have a lot of corrections, I think more boost and less timing would might work better.
 
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mj6234

Corporal
Nov 25, 2020
109
44
0
Are you running flex fuel? I see your ethanol voltage is 4.03V. For the Motiv kit, anything over 3 indicates an error and is probably reporting 100% ethanol content to the DME.

I would log timing (cyl 1 *crank) and dump that in there as well.
 
Last edited:

ClaytonT

Lurker
Jan 25, 2021
16
2
0
Are you running flex fuel? I see your ethanol voltage is 4.03V. For the Motiv kit, anything over 3 indicates an error and is probably reporting 100% ethanol content to the DME.

I would log timing (cyl 1 *crank) and dump that in there as well.
I am running straight stock fuel system on 98RON so unsure of the ethanol content, u think despite being a 98RON map the fuel could be too bad?
 

ClaytonT

Lurker
Jan 25, 2021
16
2
0
Big improvement over the mystery map. I would try the stage 2+ 91 map. You have a lot of corrections, I think more boost and less timing would might work better.
okay will give this a try thanks, can I go down fuel ratings in the tune and keep the tank of 98 I have?
 

mj6234

Corporal
Nov 25, 2020
109
44
0
I am running straight stock fuel system on 98RON so unsure of the ethanol content, u think despite being a 98RON map the fuel could be too bad?
I have never seen ethanol voltage show up as a loggable parameter until I flashed a flex fuel map. Maybe it works differently with the OTS maps, but I thought that was odd
 

Griff500

New Member
Sep 29, 2020
2
0
0
Timing corrections look post shift - I believe you can select to resolve this in the MHD options menu.

It doesn’t look like your pedal position was at 100% for the run. Perhaps try another run with the shift bog fix selected and 100% throttle (ensuring traction control is fully off).

Log looks fine to me though but hopefully an expert can advise. Your previous tune was truly awful!
 

ClaytonT

Lurker
Jan 25, 2021
16
2
0
Timing corrections look post shift - I believe you can select to resolve this in the MHD options menu.

It doesn’t look like your pedal position was at 100% for the run. Perhaps try another run with the shift bog fix selected and 100% throttle (ensuring traction control is fully off).

Log looks fine to me though but hopefully an expert can advise. Your previous tune was truly awful!

Thanks for the reply! I will get a log out tomorrow morning, I have re-tuned it to the 95RON stage two map and it still appears to have corrections when monitoring. It seems to only correct when accelerating at low rpm when cruising. Spark plugs perhaps? I think I know the option you mean, is that the anti-bog? Cheers