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      12-18-2020, 03:39 PM   #1
Wadger
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SOLVED: N54 Oscillating throttle position/surge at steady speed

Good evening all,

Been noticing a slight surging when holding steady speeds or when using cruise control.
Especially on one flat road I use for work.
It's like the engine speeds up, then slows because it sped up, spiraling to the point where I get a constant up and down.
Were talking 30rpm here however I'm concerned.

I'm running mhd 2+ full bolt on.
Index 12 injectors not sure if age
Coils, plugs, o2's, turbo cores and wastegates, dp's, intercooler, gearbox oil, boost solenoids all done well under 3k ago.
Oil changed 250 miles ago.

This has only really presented itself since the tune and I've only really started noticing now I drive it every day to work.
And once it get going it seems to consistant to Be a vacuum leak? See attached image of log.

Anyone have any thoughts? Was lucky when I run this log it done it at its worst.

Car idles fine, wot is fine, drives great. Hpfp pressures seem with range and constant under wot. Same with lpfp.

Hopefully someone has experienced similar?
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Thanks!

Last edited by Wadger; 08-08-2021 at 01:05 PM..
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      12-18-2020, 03:48 PM   #2
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Yep, had that on my MHD v9.0 maps. Went back to 8, gone. Also, if you delete adaptations, it will go away for a while...
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      12-18-2020, 03:51 PM   #3
Wadger
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Thanks for the rapid response.
It does seem adaption related maybe as it definitely appears to be getting more noticible the more I use cruise control.
Im currently running the v8 map, I'll try the reset on the throttle only?
Thanks again.
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      12-18-2020, 03:53 PM   #4
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Are you in Bukinghamshire, UK? I have a good friend working for Santander in Milton Keynes... I plan on visiting him when this bullshit is over.
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      12-18-2020, 03:54 PM   #5
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Quote:
Originally Posted by Wadger View Post
Thanks for the rapid response.
It does seem adaption related maybe as it definitely appears to be getting more noticible the more I use cruise control.
Im currently running the v8 map, I'll try the reset on the throttle only?
Thanks again.
Reset all adaptations, won't hurt ... Make sure to wait for a few minutes before re-starting, or you'll get the bouncing revs issue.
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      12-18-2020, 03:57 PM   #6
Wadger
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Ye I'm in Milton Keynes.
I've had this car a year and I'm always paranoid about it ��.
Thanks for the advice.
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      12-18-2020, 03:58 PM   #7
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I'll be going down the same route Monday on the suspect road. So I'll log again and post up the results of the reset
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      12-18-2020, 05:41 PM   #8
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Quote:
Originally Posted by torrque View Post
Yep, had that on my MHD v9.0 maps. Went back to 8, gone. Also, if you delete adaptations, it will go away for a while...
I wouldn't recommend v8 maps, several users issues with it, including throttle closures if I recall correctly.

V9 has zero throttle closures, I've ran both v7 and v9, both run fine.

Last edited by Saif2018; 12-19-2020 at 11:49 AM..
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      12-18-2020, 05:42 PM   #9
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Quote:
Originally Posted by Wadger View Post
Thanks for the rapid response.
It does seem adaption related maybe as it definitely appears to be getting more noticible the more I use cruise control.
Im currently running the v8 map, I'll try the reset on the throttle only?
Thanks again.
Recommended you flash v9 map and then relog after driving the car for a while.
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      12-19-2020, 08:19 AM   #10
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Thanks for the response. I'll flash today and log through the week going to work.
Thanks again!
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      12-19-2020, 11:52 AM   #11
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Quote:
Originally Posted by Wadger View Post
Thanks for the response. I'll flash today and log through the week going to work.
Thanks again!
No worries, post the link to the V9 log afterwards,
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      12-21-2020, 01:54 AM   #12
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I was getting these issues on V9 I thought I was just going crazy but went back to V7.1 all is good now. Also the v9 maps kept giving me Mixture 1 & 2 Codes.

Quote:
Originally Posted by Wadger View Post
Good evening all,

Been noticing a slight surging when holding steady speeds or when using cruise control.
Especially on one flat road I use for work.
It's like the engine speeds up, then slows because it sped up, spiraling to the point where I get a constant up and down.
Were talking 30rpm here however I'm concerned.

I'm running mhd 2+ full bolt on.
Index 12 injectors not sure if age
Coils, plugs, o2's, turbo cores and wastegates, dp's, intercooler, gearbox oil, boost solenoids all done well under 3k ago.
Oil changed 250 miles ago.

This has only really presented itself since the tune and I've only really started noticing now I drive it every day to work.
And once it get going it seems to consistant to Be a vacuum leak? See attached image of log.

Anyone have any thoughts? Was lucky when I run this log it done it at its worst.

Car idles fine, wot is fine, drives great. Hpfp pressures seem with range and constant under wot. Same with lpfp.

Hopefully someone has experienced similar?
Attachment 2485909
Thanks!
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      12-21-2020, 03:50 PM   #13
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I had the exact same issue after running the V7 stage 2+ tune for about a month. Heading down the road at 40mph and I could start to feel a very slight surging feeling. Got on the highway, set the cruise, and then I started to feel it again....a very slight pulsing/surging feeling. I should have tried to do a log first, but at the next exit I got off the highway and shut the car off.

I got out my cable and got MHD fired up on my phone so I could run a log when I got back on the highway. I fired the car up....got on the highway, never did the surging again.

For the hell of it, on the way home I did a WOT pull and noticed that my LPFP pressure was dipping down into the 40's.....it was getting week. I parked the car, and installed a stage 2 LPFP a few days after......never have had an issue since. I did shortly switch over to the V5 E40 tune after the new pump.

Unfortunately, since I didn't log anything....I have no idea was actually caused the pulsing feeling like that......but it sounds like exactly what was happening in the original post. Could have been the tune, could have been the LPFP, could have been something else...
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      12-22-2020, 01:18 PM   #14
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Tha ks for the input guys.

A quick update:
So I flashed v9 map and done a throttle reset.
The issue is still present, however it doesn't seem as bad. I noticed a similar surging when in 1st gear when I was rolling out the car park, but not sure if that's just me moving the pedal a little or being paranoid.
Maybe it's learning still and will fade out, in my haste to get home for dinner I forgot to do a log.
However I've put a reminder on my phone for tomorrow
On a side note, the boost kicks in significantly harder on in the lower rpm's than the v8. Wernt far of parking in the boot of the car I was overtaking

Thanks again to all that have commented
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      12-22-2020, 01:44 PM   #15
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If you end up taking a log when it's doing it, please post it up. It should be pretty beast to figure out what's going on.....maybe difficult to figure out why though...
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      12-22-2020, 03:25 PM   #16
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Quote:
Originally Posted by Wadger View Post
Tha ks for the input guys.

A quick update:
So I flashed v9 map and done a throttle reset.
The issue is still present, however it doesn't seem as bad. I noticed a similar surging when in 1st gear when I was rolling out the car park, but not sure if that's just me moving the pedal a little or being paranoid.
Maybe it's learning still and will fade out, in my haste to get home for dinner I forgot to do a log.
However I've put a reminder on my phone for tomorrow
On a side note, the boost kicks in significantly harder on in the lower rpm's than the v8. Wernt far of parking in the boot of the car I was overtaking

Thanks again to all that have commented
Drive it a couple of days and log to see if it adapts,
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      12-22-2020, 04:32 PM   #17
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I been dealing with this same issue. I'm stock so I don't think a tune is causing this.
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      12-22-2020, 10:20 PM   #18
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Quote:
Originally Posted by Wolf 335 View Post
I been dealing with this same issue. I'm stock so I don't think a tune is causing this.
Get a log when it's doing it....that will tell you if it's the throttle ocellating, the timing, the fuel, etc,etc....
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      12-23-2020, 07:04 AM   #19
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Make sure the throttle, boost psi and target etc are all logged guys, on a 3rd gear log, that's DSC fully off, WOT from 2.5k to over 6k, shift into 4th then back off after a few secs.
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      12-23-2020, 09:07 AM   #20
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Quote:
Originally Posted by Saif2018 View Post
Make sure the throttle, boost psi and target etc are all logged guys, on a 3rd gear log, that's DSC fully off, WOT from 2.5k to over 6k, shift into 4th then back off after a few secs.
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.
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      12-23-2020, 03:03 PM   #21
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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 me tioned in my first post, I also had walnut blasting done well under 5k ago.

Thanks to all responding.

Last edited by Wadger; 12-23-2020 at 03:15 PM..
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      12-23-2020, 04:08 PM   #22
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Quote:
Originally Posted by iqraceworks View Post
Get a log when it's doing it....that will tell you if it's the throttle ocellating, the timing, the fuel, etc,etc....
Do you know if logging possible via ISTA?
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