[Wiz992]

Hi guys !
I know this has been a common issue with with many N55 and N54 tunes but I'm hoping for those who fixed this can update me . My car is experiencing a vibrations/stumbling at low throttle from (50 to 75 mph). The vibration can be felt under the floor and seat on partial load (2-3K) RPM on 5th,6th and 7th (50 to 75 mph). Current Mileage (44K miles)
The issue is completely eliminated when reverting to stock map.

Please note, I'm running (93 Octane) and the below has been checked and tested:
-All possible issue-related mechanical parts has been checked.
-BMW BOSCH Spark plugs were recently installed.
-Ignition coils were tested through ISTA+ and multimeter.
-Charge pipe fittings are tight and the O-Ring is on the right place.
-Downpipe is properly installed with O2 sensors.
-MAF and MAP sensors was cleaned.
-Air intake filter was recently replaced.
-No Vacuum leaks.
-No engine codes
I have noticed ignition retardation and overboost on these maps (BM3-Stage 1/91 (ACN91, V7.1) please find attached 3 versions datalogs.
https://datazap.me/u/wiz992/bm3-stag...1?log=0&data=6

Any help would be appreciated

[n55david]

Originally Posted by Wiz992

Hi guys !
I know this has been a common issue with with many N55 and N54 tunes but I'm hoping for those who fixed this can update me . My car is experiencing a vibrations/stumbling at low throttle from (50 to 75 mph). The vibration can be felt under the floor and seat on partial load (2-3K) RPM on 5th,6th and 7th (50 to 75 mph). Current Mileage (44K miles)
The issue is completely eliminated when reverting to stock map.

Please note, I'm running (93 Octane) and the below has been checked and tested:
-All possible issue-related mechanical parts has been checked.
-BMW BOSCH Spark plugs were recently installed.
-Ignition coils were tested through ISTA+ and multimeter.
-Charge pipe fittings are tight and the O-Ring is on the right place.
-Downpipe is properly installed with O2 sensors.
-MAF and MAP sensors was cleaned.
-Air intake filter was recently replaced.
-No Vacuum leaks.
-No engine codes
I have noticed ignition retardation and overboost on these maps (BM3-Stage 1/91 (ACN91, V7.1) please find attached 3 versions datalogs.
https://datazap.me/u/wiz992/bm3-stage-1-acn91-v64-v71?log=0&data=6

Any help would be appreciated

bet you're getting detonation

[Wiz992]

Originally Posted by Phantom10R

bet you're getting detonation

I'll try replacing the ignition coils which i don't think it's the cause and clean the intake manifold which is not that dirty (44K miles). As for Air/fuel mixture the readings are fine. No knocks detected.

[thejeremyman9]

FYI, overboost is typical in BM3 logs. So that's not abnormal to your car.

The logs you posted are WOT. Can you log ~5 seconds of the issue occuring?

Also, you said you are running 93 fuel, and this is the ACN 91 map. That's fine, but since the issue goes away on stock map, have you tried either the 91 map or the 93 map to see if you still have the issue? The ACN map overall is less refined from what i have seen. The load throttle high load may not be as dialed in.

[Wiz992]

Originally Posted by thejeremyman9

FYI, overboost is typical in BM3 logs. So that's not abnormal to your car.

The logs you posted are WOT. Can you log ~5 seconds of the issue occuring?

Also, you said you are running 93 fuel, and this is the ACN 91 map. That's fine, but since the issue goes away on stock map, have you tried either the 91 map or the 93 map to see if you still have the issue? The ACN map overall is less refined from what i have seen. The load throttle high load may not be as dialed in.

Will do. I tried 91 map (Log available in the link) and the issue still persisting. The vibration just feels you're in a high gear low RPM situation (The drivetrain under stress).

[Wiz992]

Originally Posted by thejeremyman9

FYI, overboost is typical in BM3 logs. So that's not abnormal to your car.

The logs you posted are WOT. Can you log ~5 seconds of the issue occuring?

Also, you said you are running 93 fuel, and this is the ACN 91 map. That's fine, but since the issue goes away on stock map, have you tried either the 91 map or the 93 map to see if you still have the issue? The ACN map overall is less refined from what i have seen. The load throttle high load may not be as dialed in.

Hi thejeremyman9 !
Please find the below 4 logs taken taken today on partial throttle. You can see the advance ignition timings from (49 mph) where the vibrations start.

https://datazap.me/u/wiz992/stage-1-...0?log=0&data=6

https://datazap.me/u/wiz992/log-1606149385?log=0&data=6

[Pray for Mojo]

Your AFR is spiking to 16:1, I have a similar problem at low speed when I cold start and drive off. I get AFR spikes I can see on my iPhone BM3 gauges to approximately 16:1 which causes the car to stumble, this only happens around 10mph.

[Wiz992]

Originally Posted by Pray for Mojo

Your AFR is spiking to 16:1, I have a similar problem at low speed when I cold start and drive off. I get AFR spikes I can see on my iPhone BM3 gauges to approximately 16:1 which causes the car to stumble, this only happens around 10mph.

Yeah I've heard that, Cold start causes AFR spikes and stumbling for some and even though with the cold start being OFF it didn't make any difference. Only three things left to do (Replace ignition coils that has no codes or misfires, cleaning the injectors and intake manifold).

[Pray for Mojo]

Originally Posted by Wiz992

Yeah I've heard that, Cold start causes AFR spikes and stumbling for some and even though with the cold start being OFF it didn't make any difference. Only three things left to do (Replace ignition coils that has no codes or misfires, cleaning the injectors and intake manifold).

It seems tune/fuel related so I wouldn't bother with coils or your intake.

[Wiz992]

Originally Posted by Pray for Mojo

It seems tune/fuel related so I wouldn't bother with coils or your intake.

The tune used to be smooth. specially it's a BM3-OTS map that has been tested with many N55-EWG engines. I know sometimes the tune might respond differently to different models/systems but I feel it's weak chance and I'm using 93 Octane fuel on 91 maps (V6.4, V7.1 and ACN91). so that's why i eliminated those possibilities.

[thejeremyman9]

Originally Posted by Wiz992

Hi thejeremyman9 !
Please find the below 4 logs taken taken today on partial throttle. You can see the advance ignition timings from (49 mph) where the vibrations start.

https://datazap.me/u/wiz992/stage-1-...0?log=0&data=6

https://datazap.me/u/wiz992/log-1606149385?log=0&data=6

All of these logs except log 2 have 1 or 2 knocks in them and negative timing... i dont think the negative timing is normal, even at part throttle? I don't look at enough part throttle logs to know for certain though. Log 2 has way higher/consistent timing and no knock. Did the issue happen during log 2?

So just to confirm, you tried different versions of the normal 91 map and you also tried the ACN 91 map and its the same in all cases? Did you try the 93 map?

Also, just because it doesnt happen on stock tune doesnt necessarily mean the tune itself is the problem. It could just be that the tune reveals/exacerbates a hardware problem that isnt present on the stock (conservative) tune.

[akgambino]

Originally Posted by Wiz992

Hi thejeremyman9 !
Please find the below 4 logs taken taken today on partial throttle. You can see the advance ignition timings from (49 mph) where the vibrations start.

https://datazap.me/u/wiz992/stage-1-...g=0&data=6

https://datazap.me/u/wiz992/log-1606149385?log=0&data=6

Looks to me like load and boost starts running away after 52% pedal input which may point to a throttle mapping issue. I've seen this issue before on early pwg ots maps which led to superknocking codes thrown on my car and very bad stumbling. Almost as if the throttle mapping leads to big increase in load and boost but the timing isn't properly aligned to this demand which causes misfire and knock. Your car once it hit 52% throttle is essentially requesting boost and load as if it was 100% throttle.

[Wiz992]

Originally Posted by thejeremyman9

All of these logs except log 2 have 1 or 2 knocks in them and negative timing... i dont think the negative timing is normal, even at part throttle? I don't look at enough part throttle logs to know for certain though. Log 2 has way higher/consistent timing and no knock. Did the issue happen during log 2?

So just to confirm, you tried different versions of the normal 91 map and you also tried the ACN 91 map and its the same in all cases? Did you try the 93 map?

Also, just because it doesnt happen on stock tune doesnt necessarily mean the tune itself is the problem. It could just be that the tune reveals/exacerbates a hardware problem that isnt present on the stock (conservative) tune.

As per the datalog.. it appears the ignition timings are mostly uniform except for some parts where the advance ignition and knocks originates (below 2K RPM) which leads to 1-2 seconds vibration unless the engine is revved up to 2.5K RPM. As for 91 maps, V7.1 was acting roughly since first flash. V6.4 was smooth for a long time (which was my option B ) and recently started to behave like V7.1. As we know, V7.1 has a higher boost target and torque than V6.4 so maybe that's a reason for a faulty part to start showing its defects. As for ACN91, the situation was the same as V7.1 (Only overboost issues).
I 've never tried 93 map.

So this morning, i bought 2 OEM coils and will try target the weak coils if any is there. fingers crossed

[Wiz992]

Originally Posted by akgambino

Looks to me like load and boost starts running away after 52% pedal input which may point to a throttle mapping issue. I've seen this issue before on early pwg ots maps which led to superknocking codes thrown on my car and very bad stumbling. Almost as if the throttle mapping leads to big increase in load and boost but the timing isn't properly aligned to this demand which causes misfire and knock. Your car once it hit 52% throttle is essentially requesting boost and load as if it was 100% throttle.

EXACTLY!!. That's the my point. I already informed Halim yesterday about this. Awaiting his input

[Wiz992]

Originally Posted by Wiz992

EXACTLY!!. That's the my point. I already informed Halim yesterday about this. Awaiting his input

Partial throttle/full load explanation: These cars are torque based, so at this pedal input it will make whatever torque is requested. Since ignition timing is low it will increase boost pressure to reach its target.

[thejeremyman9]

Originally Posted by Wiz992

As per the datalog.. it appears the ignition timings are mostly uniform except for some parts where the advance ignition and knocks originates (below 2K RPM) which leads to 1-2 seconds vibration unless the engine is revved up to 2.5K RPM. As for 91 maps, V7.1 was acting roughly since first flash. V6.4 was smooth for a long time (which was my option B ) and recently started to behave like V7.1. As we know, V7.1 has a higher boost target and torque than V6.4 so maybe that's a reason for a faulty part to start showing its defects. As for ACN91, the situation was the same as V7.1 (Only overboost issues).
I 've never tried 93 map.

So this morning, i bought 2 OEM coils and will try target the weak coils if any is there. fingers crossed

How are you going to choose which coils to replace?

If the problem wasnt happening on v6.4 originally then later started to happen on that map then its almost certainly a hardware issue and not a tune issue.

You could try running some techron through your tank, it works well for some people per other threads, incase it is injector-related.

[Wiz992]

Originally Posted by thejeremyman9

How are you going to choose which coils to replace?

If the problem wasnt happening on v6.4 originally then later started to happen on that map then its almost certainly a hardware issue and not a tune issue.

You could try running some tachyon through your tank, it works well for some people per other threads, incase it is injector-related.

True. first try would be 2 coils installed incrementally on cylinders : (1&2,3&4,5&6) then it would be random selections. So by this, I'd feel some changes if any are worn out. Because I don't want to spend 310$ for 6 coils that might be not the cause of the issue.

Tachyon and intake manifold cleaner would be my step 2.

[Pray for Mojo]

You can get Eldors for around $200 shipped. I really don't think this is ignition related and the difference between 6.4 and 7.1 is huge, Halim changed the whole tuning philosophy from my understanding. My car sounds quite a bit different on the old tunes.

[Wiz992]

Hi guys,
So today as i was trying to target the weak coils, i noticed 40% improvement and felt still there are more than 2 weak coils. So i decided to pick the remaining coils. After replacing all the coils i've noticed a huge improvement (85% less rear vibrations/stumbling and ofcourse sharper throttle response).

So 15% of low vibration is still present and that might be due to dirty throttle body (Layer of oil residue has been noticed inside the CP) or clogged injectors.

[Wiz992]

Originally Posted by Pray for Mojo

You can get Eldors for around $200 shipped. I really don't think this is ignition related and the difference between 6.4 and 7.1 is huge, Halim changed the whole tuning philosophy from my understanding. My car sounds quite a bit different on the old tunes.

Shipping Eldors to my place would take approximately 2 weeks (Express shipping is not available outside the US) so i wanted an urgent fix on this and went for OEM.

That's true. V6.4 is way smoother than V7.1. After replacing the coils V7.1 was responding as mentioned above. However, ACN91 was rough as always. Later on, I'll test the car on V6.4.

[Wiz992]

Hi guys !

unfortunately the rear vibrations came back. It’s like coils reduced it for 2 days and now has returned to the old behavior. This only happens only high boost/Low RPM (below 3K) specially on high gears (5,6&7). I’m not sure what else to check other than the flex disk and engine mounts which i hardly suspect due to irrelative symptoms.

Already started running techron just in case.

[akgambino]

Originally Posted by Wiz992

Hi guys !

unfortunately the rear vibrations came back. It’s like coils reduced it for 2 days and now has returned to the old behavior. This only happens only high boost/Low RPM (below 3K) specially on high gears (5,6&7). I’m not sure what else to check other than the flex disk and engine mounts which i hardly suspect due to irrelative symptoms.

Already started running techron just in case.

What spark plug gap? I see u have relatively new oem plugs, maybe try the colder ngk plugs and gap properly?