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BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Powertrain and Drivetrain Discussions > N54 Turbo Engine / Drivetrain / Exhaust Modifications - 335i > SOLVED: N54 Oscillating throttle position/surge at steady speed



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      12-23-2020, 03:41 PM   #23
Saif2018
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Quote:
Originally Posted by iqraceworks View Post
They are having the issues at light throttle...cruising on the highway etc,etc....

That's when they want to run a log, when it's actually doing the pulsing/ocellating. ....I don't think doing a log at wide open throttle is going to show anything.
If it's at light throttle and cruising only then yes your right.
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      12-23-2020, 03:43 PM   #24
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Quote:
Originally Posted by Wadger View Post
Good evening all

I done a couple logs on datazap, hopefully the links work.

The weather was really bad on way home today so didn't get much chance, but I got a few logs in that show the issues.
And it definitely seems throttle related to me, it only does it when really light throttle, or cruise control on what I beleive to me a very slight decline. Also the RPM and o2 seem in my inexperienced opinion, reactive to the throttle.
I found it very noticeable today when pulling off or rolling round a roundabout, as I was being super light footed.

But as soon as I fully let off or apply a little more throttle it's absolutely fine.

It defintely seems better when using cruise control, but it felt worse today at really low speed. Maybe due to the fact I never drive like this, due to the weather today.

In a side note, I'm getting some timing corrections while cruising, is this normal?

https://datazap.me/u/ryanw/friday-cruise-control
https://datazap.me/u/ryanw/wed-cruise-control
https://datazap.me/u/ryanw/wed-23-jumpy

Edit: in addition to the work metioned in my first post, I also had walnut blasting done well under 5k ago.

Thanks to all responding.
Timing corrections during light throttle and cruising is normal.

Just had a look at the Friday cruise and cruise control logs, throttle position is fluctuating but accelerator position is fixed dead at 0%

The last one is the worst.

If you flash stage 0 map, do you have the same issue?

Last edited by Saif2018; 12-23-2020 at 03:54 PM..
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      12-23-2020, 03:57 PM   #25
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Thanks for the reply.
That was with cruise control on. Would accelerating through cruise control register as accelerator movement? Or only throttle body position?
Regardless, when I hold a steady 10% throttle or when on cruise control, under very little load, the throttle body opens and closes, causing the staggering.

I assume you agree it's the actual throttle body causing the problem? Just need to identify what parameters are causing it to actuate in this manner?

I'll flash stage 0 tomorrow and give it a try.
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      12-23-2020, 04:11 PM   #26
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Quote:
Originally Posted by Wadger View Post
Thanks for the reply.
That was with cruise control on. Would accelerating through cruise control register as accelerator movement? Or only throttle body position?
Regardless, when I hold a steady 10% throttle or when on cruise control, under very little load, the throttle body opens and closes, causing the staggering.

I assume you agree it's the actual throttle body causing the problem? Just need to identify what parameters are causing it to actuate in this manner?

I'll flash stage 0 tomorrow and give it a try.
Accelerating from cruise control would cut cruise control off, so it should register.

Also you may as well clean the map sensor and throttle body if flashing to stage 0 doesn't make any difference.

Some of the guys on boost addict also said its a DME firmware issue and resolved it by flashing the Ecu's (DME and TCU) to the latest version using ISTA/P.
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      12-24-2020, 06:54 PM   #27
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I dont see you have done anything with VAnos. Time to look at the exhaust solenoid, there is another thread - https://www.e90post.com/forums/showthread.php?t=1370760

Reset vanos adapts first. then clean/replace solenoids.. And it might clean up for a while. .. ITs probably mileage related and some stuff that the DME cant deal with at short intervals..

I had it on a stock bin in about 2016 on a N54 with 130K miles.. Would go away for a while and then come back
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      12-25-2020, 02:09 PM   #28
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Quick update.
So I drove home a little while ago and noticed the shudder on 30mph cruise control. Same shudder as well when feathering throttle round roundabouts.
So I got home and flashed stage 0.
Strsiggt away the car felt smoother and I couldn't replicate any shudder cruising with cc at 30 mph, 70mph and on roundabouts.
So I came home and flashed the v7 stage 2+. Again I couldn't replicate any shuddering at all.
Im hoping that's cured it, but I'm so paranoid I will report back during next week with how it goes.
I also prefer the boost curve of the v7, kicks like a mule ��

In a side note, for the firdt time I has a issue after flashing. Upon starting the engine, I was pulling off in D3. I couldn't even manually get it to go into first or second gear. However after about 20 meters it dropped into second and full functionality restored. This happened upon flashing the v7 map. Anyone had this?

Thanks again for all the continued support and I hope everyone is having a great Christmas!
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      12-25-2020, 02:39 PM   #29
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Quote:
Originally Posted by Wadger View Post
Quick update.
So I drove home a little while ago and noticed the shudder on 30mph cruise control. Same shudder as well when feathering throttle round roundabouts.
So I got home and flashed stage 0.
Strsiggt away the car felt smoother and I couldn't replicate any shudder cruising with cc at 30 mph, 70mph and on roundabouts.
So I came home and flashed the v7 stage 2+. Again I couldn't replicate any shuddering at all.
Im hoping that's cured it, but I'm so paranoid I will report back during next week with how it goes.
I also prefer the boost curve of the v7, kicks like a mule ��

In a side note, for the firdt time I has a issue after flashing. Upon starting the engine, I was pulling off in D3. I couldn't even manually get it to go into first or second gear. However after about 20 meters it dropped into second and full functionality restored. This happened upon flashing the v7 map. Anyone had this?

Thanks again for all the continued support and I hope everyone is having a great Christmas!
V7 is my favourite. V9 was ok . I found it smooth and nicer for around town driving but the boost curve is different and a little unpredictable. I wouldn't be surprised if your issue was the tune itself. Enjoy v7.
Yes starting off is D3 after flashing is completely normal. Just drive slow till your up to a 3rd gear speed then it will reset itself. It only seems to do this if you flash , wait a min then start the car and drive.
I have flashed then left the car overnight and it didn't do that.
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      12-25-2020, 03:26 PM   #30
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Ye the 9 was OK. I flashed the 7 a while back but only shortly while experimenting.
The way it kicked today scared the crap out of me tbh. Felt way faster than it did before.

Hopefully the issue is fixed, will have to wait and see.
I am worried about the torque converter, as it seems this has fixed it for a few people and seems a common issue explained under failure symptoms for torque converters in general.
However it is of course difficult to 'compare' shuddering symptoms over written descriptions on various articles etc.

Thanks for your response!
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      12-25-2020, 06:14 PM   #31
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As far as tunes go......I either run the V5 E40 tune, or the V7 stage 2+ 93 tune.
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      12-25-2020, 10:32 PM   #32
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Good to hear v7 is running better, also prefer it over v9.
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      03-05-2021, 11:53 AM   #33
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Hi Everyone,

Its back! The issue has presented itself yet again, after all this time in the clear..

I was running v7 for all this time without issue, however I reflashed to reduce burble and boom its back.
I also just flashed v9 to see if it goes and it hasn't...
Is it pot luck when I flash, or a weird adaption that if doesn't happen straight away will keep me clear.?
I'm stumped at what could be causing this.

I ran the mhd monitor again and as previous, I feel it is too consistant I think to be a fuel/air issue. It has to be either electrical hardware (maybe throttle position sensor?), or software... Please correct my theory by all means

Time to whip out the solenoids and give them a clean, and maybe the tmap sensor.
Other than that I don't know where else to dig.
FYI on mon/Tues I fixed a leaking oil filter housing, and fitted a new rocker cover with gasket.
I also checked for wet plugs and other leaks as I left it over night. All looks good.

All input is welcome as always!

Thanks!
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      08-08-2021, 11:47 AM   #34
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SOLVED

I have fixed the surging and oscillating issue by flashing back to stock with mhd.
This worked when I removed the original backup from my phone and let Mhd download the appropriate map. I then reflashed back to my previous mhd map.

The surging in first under light throttle was getting quite severe.. However I'm glad to say it's back to being buttery smooth.

I have no idea what adaption or other input was causing this, but atleast it's fixed!

Thanks again to everyone that had any input!
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      09-20-2021, 02:40 PM   #35
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Quote:
Originally Posted by Wadger View Post
SOLVED

I have fixed the surging and oscillating issue by flashing back to stock with mhd.
This worked when I removed the original backup from my phone and let Mhd download the appropriate map. I then reflashed back to my previous mhd map.

The surging in first under light throttle was getting quite severe.. However I'm glad to say it's back to being buttery smooth.

I have no idea what adaption or other input was causing this, but atleast it's fixed!

Thanks again to everyone that had any input!
Is the issue still eliminated or has it come back? I have been dealing with this issue for 2 years.
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      09-22-2021, 07:09 AM   #36
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Wadger "The surging in first under light throttle was getting quite severe.. However I'm glad to say it's back to being buttery smooth."

Was it also like this? -Standstill, decent/normal amount of gas, cars moves but no boost/let say slow response, sudden arrival of toque? Kind of feeling like being pulled on a rubber string?
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      09-22-2021, 10:11 AM   #37
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Quote:
Originally Posted by streetpro View Post
Wadger "The surging in first under light throttle was getting quite severe.. However I'm glad to say it's back to being buttery smooth."

Was it also like this? -Standstill, decent/normal amount of gas, cars moves but no boost/let say slow response, sudden arrival of toque? Kind of feeling like being pulled on a rubber string?
This sounds more like bad wastegates or you're lugging the car.
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      09-23-2021, 04:11 AM   #38
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WG/turbos were replaced, vanos solenoids new, boost valves/solenoids replaced, all vacuum lines tight, vacuum in canisters present, Forge DVs installed, metal CP, new IC, new RB check valve...
the car has had this weird habit right from the beginning - even before I have replaced all those mentioned... apart from this there is no issue, no codes...
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      09-26-2021, 08:41 AM   #39
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Hi All,

Apologies for the delayed response. You know how life gets

Regarding the wastegate theory, I'm not sure if this was aimed at me or another comment so apologies if I'm wrong.. However my car had new wastegate flappers installed around 10k ago. The boost does suddenly hit hard, however this is due to the map, as monitored on the wgdc values. At low acceleration you can hear the turbos spinning up in time with the wgdc variations.
I don't quite understand what lugging the car means, however I was specifically talking about a solid/steady throttle input.
Since my post stating I have solved the problem, I am still issue free. The main tests for me has been when using cruise control on a very slight decline and when navgaitijg my local multi story caroarj in first gear. The cruise control scenario would build quite a judder, especially in a certain bit of road. This does not occur any more.
The multi story car park issue would cause a slight(but noticeable) surge in acceleration, when trying to pull away slowly with the smallest of throttle input. This could be explained like a lag, which surged and then let's off due to over shooting. This is all occurs with a steady/unchanging small throttle input.
This does not occur also.

Just for clarification on the process I completed.

Input cable and load mhd

Flash back to stock (the full 20+ min flash which removes mhd) Note: I removed/relocated the file mhd automatically saved of my original stock map, so that mhd would download the latest stock file for my ecu etc.

Once this had completed, I let car rest and started it up for a few mins. I'm not sure if this makes a difference, but thought I would let the car operate on this file before I again removed it.

Now turn off car and follow the procedure to flash back your mhd stage 2 or whatever.

That's it.

Hope this clarifies a few things for anyone with questions. Feel free to pm me etc if you would like any more info.
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      09-27-2021, 05:02 AM   #40
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I have tackled this issue once more, based on this experience - back to map V7, reset of Vanos, throttle flap adaptations...
Car has ran in the fault mode after the first start up, cleared the codes (throttle flap fault), idled just fine, all good...
a slight improvement after-all or I am just too used to it :-)
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      09-27-2021, 01:10 PM   #41
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Quote:
Originally Posted by Wadger View Post
SOLVED

I have fixed the surging and oscillating issue by flashing back to stock with mhd.
This worked when I removed the original backup from my phone and let Mhd download the appropriate map. I then reflashed back to my previous mhd map.

The surging in first under light throttle was getting quite severe.. However I'm glad to say it's back to being buttery smooth.

I have no idea what adaption or other input was causing this, but atleast it's fixed!

Thanks again to everyone that had any input!
+1, thanks for sharing. I can't remember how long I've been trying to correct this issue, what you suggested worked.
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