[Nandohatesyou]

Good afternoon, I've worked myself into a headache trying to figure out why my M2 begins stumbling at higher rpms. I've attached two logs (2nd gear WOT) to try and figure out the cause of the stumbling. Opinions anyone?

Mods currently: Race Intercooler (BMS), Catless DP, Upgraded CP, Turner Motorsports CF Intake, Stage 2 OTS ACN 91 Tune (BM3). Thanks Mike @ XPH!

Here's what I know so far (which doesn't say much):

1. It seems that when the stumbling occurs, my HPFP actual is quite a bit below the target.

2. It seems worse, more pronounced when I do it in DSC OFF than regular Comfort.

3. No knock is registered.

4. Stock spark plugs are on the car.

I believe the problems are around the HPFP, but again thats just my guess from looking at the logs. Is this a common issue with an n55 M2? My old M235i never had this issue, but I also had NGK .22 gapped plugs.

Here are the logs:

https://www.bootmod3.net/log?id=61a3...0b43123be407f4

https://www.bootmod3.net/log?id=61a3...0b43123be40807

[Wolfman’s Brother]

Something is up, to state the obvious and you’re right to be thinking HPFP as it’s not meeting target like you’ve already identified.

Was this in Sport+? Were you letting out when you detected the stuttering or breakup? I notice you shifted out around 5500….

How many miles on the car? How many miles on the plugs?

I’d be thinking about flashing back to the stock tune and seeing if it provides any relief, while also looking at HPFP upgrades and any Black Friday deals that Dorch may be offering.

Good luck getting it sorted.

[AdventureNoodle]

Originally Posted by Wolfman’s Brother

Something is up, to state the obvious and you’re right to be thinking HPFP as it’s not meeting target like you’ve already identified.

Was this in Sport+? Were you letting out when you detected the stuttering or breakup? I notice you shifted out around 5500….

How many miles on the car? How many miles on the plugs?

I’d be thinking about flashing back to the stock tune and seeing if it provides any relief, while also looking at HPFP upgrades and any Black Friday deals that Dorch may be offering.

Good luck getting it sorted.

This same thing has been happening to me on the stage 2 multimap. The stand alone maps don't seem to have this issue. My buddy (samsamdar) with a catless stage 1 M2 manual is having the same issue as well on the stage 1 multimap ACN91. The standalone map seems to be perfectly okay though. I have NGK plugs gapped to .020 so I'm not sure it's a plug issue tbh. I do have a log with the stutter that I can post if required.

[Nandohatesyou]

Originally Posted by Wolfman’s Brother

Something is up, to state the obvious and you’re right to be thinking HPFP as it’s not meeting target like you’ve already identified.

Was this in Sport+? Were you letting out when you detected the stuttering or breakup? I notice you shifted out around 5500….

How many miles on the car? How many miles on the plugs?

I’d be thinking about flashing back to the stock tune and seeing if it provides any relief, while also looking at HPFP upgrades and any Black Friday deals that Dorch may be offering.

Good luck getting it sorted.

Yes, everything point's to that but I feel that more people would be reporting this issue if it was more prevalent amongst Stage 2 users..

I was in DSC OFF and yes I was letting off the throttle as I was scared as to what could happen if it fails lol, what can honestly happen if I push it hard and the fuel isn't being delivered?

I will flash to Stage 1, then back to Stock tune and will definitely be looking at Dorch, thank you!

[Nandohatesyou]

Originally Posted by AdventureNoodle

This same thing has been happening to me on the stage 2 multimap. The stand alone maps don't seem to have this issue. My buddy (samsamdar) with a catless stage 1 M2 manual is having the same issue as well on the stage 1 multimap ACN91. The standalone map seems to be perfectly okay though. I have NGK plugs gapped to .020 so I'm not sure it's a plug issue tbh. I do have a log with the stutter that I can post if required.

I'm going to try Stage 1 standalone and report back, never had this issue with my M235i

[AdventureNoodle]

Originally Posted by Nandohatesyou

I'm going to try Stage 1 standalone and report back, never had this issue with my M235i

Originally Posted by Nandohatesyou

I'm going to try Stage 1 standalone and report back, never had this issue with my M235i

Keep me posted!

[Nandohatesyou]

Originally Posted by AdventureNoodle

Keep me posted!

Flashed to Stage 1 ACN, same issue. The fuel pump keeps up till around 4500 rpms when it just hits like a wall or something and crashes.

Dorch is having a 15% of sale and I might just pull the trigger on a HPFP from them.

Here is the log: https://www.bootmod3.net/log?id=61a5...0b4311b85e9f63

[AdventureNoodle]

Originally Posted by Nandohatesyou

Flashed to Stage 1 ACN, same issue. The fuel pump keeps up till around 4500 rpms when it just hits like a wall or something and crashes.

Dorch is having a 15% of sale and I might just pull the trigger on a HPFP from them.

Here is the log: https://www.bootmod3.net/log?id=61a5...0b4311b85e9f63

Originally Posted by Nandohatesyou

I'm going to try Stage 1 standalone and report back, never had this issue with my M235i

Originally Posted by Nandohatesyou

Flashed to Stage 1 ACN, same issue. The fuel pump keeps up till around 4500 rpms when it just hits like a wall or something and crashes.

Dorch is having a 15% of sale and I might just pull the trigger on a HPFP from them.

Here is the log: https://www.bootmod3.net/log?id=61a5...0b4311b85e9f63

You get the same misfire / stumbling issue? Yeah that's interesting as hell. Does it happen on the stock map too? If Dorsch has a sale definitely go ahead and upgrade

[Nandohatesyou]

Originally Posted by AdventureNoodle

You get the same misfire / stumbling issue? Yeah that's interesting as hell. Does it happen on the stock map too? If Dorsch has a sale definitely go ahead and upgrade

That'll be my last step before buying the upgraded HPFP.. anything on your end? It's odd because its keeping up right till 4500RPM and it's driving me nuts lol!!

[AdventureNoodle]

Originally Posted by Nandohatesyou

That'll be my last step before buying the upgraded HPFP.. anything on your end? It's odd because its keeping up right till 4500RPM and it's driving me nuts lol!!

Originally Posted by Nandohatesyou

I'm going to try Stage 1 standalone and report back, never had this issue with my M235i

Originally Posted by Nandohatesyou

Flashed to Stage 1 ACN, same issue. The fuel pump keeps up till around 4500 rpms when it just hits like a wall or something and crashes.

Dorch is having a 15% of sale and I might just pull the trigger on a HPFP from them.

Here is the log: https://www.bootmod3.net/log?id=61a5...0b4311b85e9f63

Originally Posted by Nandohatesyou

That'll be my last step before buying the upgraded HPFP.. anything on your end? It's odd because its keeping up right till 4500RPM and it's driving me nuts lol!!

Since I switched to the stage 2 stand alone maps I have had no issues

[Nandohatesyou]

Anyone* else have any input or ideas?

[Nandohatesyou]

Ended up ordering a Stage 1 HPFP from Dorch.

[Wolfman’s Brother]

Originally Posted by Nandohatesyou

Ended up ordering a Stage 1 HPFP from Dorch.

How many miles are on your car?

[Nandohatesyou]

Originally Posted by Wolfman’s Brother

How many miles are on your car?

About to hit the 40k mile mark, I had 50k on my M235i Stage 2 for 28k of those miles and no issues

[Wolfman’s Brother]

Originally Posted by Nandohatesyou

About to hit the 40k mile mark, I had 50k on my M235i Stage 2 for 28k of those miles and no issues

Really appreciate you sharing as it gives others like myself a look at what they can expect.

How many of those 40k were tuned?

The upside here is once upgraded you’re clear for E30 or if not near E85, more power with a custom tune that can take advantage of the additional fuel flow.

If I’d ordered a Dorch I’d be emailing Bend Calibration next

[AdventureNoodle]

Originally Posted by WolfmanÂ’s Brother

Really appreciate you sharing as it gives others like myself a look at what they can expect.

How many of those 40k were tuned?

The upside here is once upgraded you’re clear for E30 or if not near E85, more power with a custom tune that can take advantage of the additional fuel flow.

If I’d ordered a Dorch I’d be emailing Bend Calibration next

I got the Dorch stage 2 pump and it fixed all my stumbling issues hahah. I got the stage v2 cause I plan on running full E85 on the stock turbo and maxing it out till it blows, then going big turbo

[rtl32]

I also had the same issue, around 40k I started stumbling high rpm, mid pull gunshots and burbles on Stage 2 93. Forget about trying E on that. Upgraded to Dorch stage 1 and the issue is completely resolved. Does come back above E40 though.

[Nandohatesyou]

Originally Posted by rtl32

I also had the same issue, around 40k I started stumbling high rpm, mid pull gunshots and burbles on Stage 2 93. Forget about trying E on that. Upgraded to Dorch stage 1 and the issue is completely resolved. Does come back above E40 though.

Correct, I also upgraded to Dorch Stage 1 and it solved my issue, except as you stated when I go overboard on E it resurfaces lol.

[Wolfman’s Brother]

I’m at 15k miles. Sounds like I may need to start a Dorch stage 2 fund.

[Nandohatesyou]

Originally Posted by Wolfman’s Brother

I’m at 15k miles. Sounds like I may need to start a Dorch stage 2 fund.

I would honestly opt for the Stage 2, Stage 1 your E85 usage will be very very limited..

[rtl32]

Originally Posted by Nandohatesyou

I would honestly opt for the Stage 2, Stage 1 your E85 usage will be very very limited..

Stage 1 has been working well for me up to mid/high 40% on Stage 2+ multimap version 1.2 with the revised 29xx psi pump targets. Big improvement over barely being able to go above 30% on the previous 24xx psi targets of the non-customrom Stg2+ E30 or earlier multimaps.

[Nandohatesyou]

Originally Posted by rtl32

Stage 1 has been working well for me up to mid/high 40% on Stage 2+ multimap version 1.2 with the revised 29xx psi pump targets. Big improvement over barely being able to go above 30% on the previous 24xx psi targets of the non-customrom Stg2+ E30 or earlier multimaps.

Around how many gallons of E85 would you estimate that is?