[thermal]

n55 m2 with 20k miles, upgraded fmic,chargepipe,mst turboinlet,catless dp.

Was running bm3 stage 2 tune and on a 3rd gear pull around 5400rpm got a weird power cut, almost identical to hitting rev limiter. I pulled over and looked at the codes and got a:
152508 Super knocking cylinder 5: injection shutdown.

After looking up the code and finding out that it's pretty serious I got the car home and started researching the causes. There isn't one specific one but could range anywhere from bad spark plugs/bad gas/loose chargepipe/loose downpipe on the turbo side.

So got looking into all the parts installed, making sure chargepipe is good and downpipe is tight, I also replaced the spark plugs (oem+oem gap) Had less than quarter of a tank, so changed gas stations as well just in case. Flashed the car back to stock and logged some 3rd gear pulls:
https://www.bootmod3.net/log?id=635a...729b7bba2e6e31
https://www.bootmod3.net/log?id=635a...90c66de08d066e

Felt great, car pulled no hesitation I thought I fixed the issue (the spark plugs were 20k old), so I moved forward and flashed bm3 stage1(91octane with 93 in the tank):
https://www.bootmod3.net/log?id=635b...729b7bba2e6e89
Instead of a rev limit feeling, it now felt more like a hesitation which you can see it happen on the log. Checked codes and nothing came up and logged one more pull. Same thing happened again, not as aggressively as the first time on stg2(93octane) but more now as a form of a stutter.:
https://www.bootmod3.net/log?id=635b...90c66de08d07a1
(if you read this far thank you lol)
I am now back onto stock flash, but would like to figure this out. Any one have a similar issue or see anything funky in the logs? My next step is going to be changing ignition coils. At 20k miles I don't think it would be an injector issue either.

[Joebie]

BM3 recommends NGK SILZKBR8D8S (97506) gapped to .022-.023 for tuned cars. Maybe that would help.

https://bootmod3.atlassian.net/servi...rticle/2558945

I also noticed that your HPFP is really struggling to meet demand. Your AFR spikes to 18 at high RPMs which is really sketchy. Could be a fueling issue. If you go super lean like that especially at high rpm and high load you can definitely do some serious damage as the codes you found are trying to warn you about.

But im not a pro so maybe someone who is can chime in.

[thermal]

Originally Posted by Joebie

BM3 recommends NGK SILZKBR8D8S (97506) gapped to .022-.023 for tuned cars. Maybe that would help.

https://bootmod3.atlassian.net/servi...rticle/2558945

I also noticed that your HPFP is really struggling to meet demand. Your AFR spikes to 18 at high RPMs which is really sketchy. Could be a fueling issue. If you go super lean like that especially at high rpm and high load you can definitely do some serious damage as the codes you found are trying to warn you about.

But im not a pro so maybe someone who is can chime in.

That is one thing I overlooked, the hpfp target and hpfp actual looks concerning.

thank you so much for pointing that out. 20,000 miles I didn't think I would have fuel pump issues so soon.
very weird, under the stock log, it looks like the fuel pump is keeping up, under stg1, looks like it can't at all

[ZM2]

Looks like the stock HPFP is toast. Time to get a Dorch Stage 2 so you can run E50.

You made the right call on stock plugs and gap. The PTF recommendation is silly and not needed unless you’re >500whp.

[thermal]

Originally Posted by ZM2

Looks like the stock HPFP is toast. Time to get a Dorch Stage 2 so you can run E50.

You made the right call on stock plugs and gap. The PTF recommendation is silly and not needed unless you’re >500whp.

Gonna have to cant be putting a stock one back in

[Joebie]

Originally Posted by ZM2

Looks like the stock HPFP is toast. Time to get a Dorch Stage 2 so you can run E50.

You made the right call on stock plugs and gap. The PTF recommendation is silly and not needed unless you’re >500whp.

I got NGKs sitting in my garage that i intend to install this weekend with a stage 1 flash. Seems like alot of people say what you did in this comment, but then again PTF are the pros right like its hard to ignore their advice too and im not sure what to do...

[ZM2]

Originally Posted by Joebie

I got NGKs sitting in my garage that i intend to install this weekend with a stage 1 flash. Seems like alot of people say what you did in this comment, but then again PTF are the pros right like its hard to ignore their advice too and im not sure what to do...

Been there done that. Idk why PTF suggests gapping down just for Stg 1/2 tunes.

I’m running the NGK’s at out of the box gap 0.030” on Stg 2+ MM with E50 and a TTE460 dyno’ed at 480whp and my car runs so smooth. Any time I gapped down, it just caused hiccups and power issues.

[AmuroRay]

NGK's also have quality control issues, and plenty of people have trouble when switching out I would stick with stock - it looks like it could be a LPFP or a HPFP issue though.

[Joebie]

I contacted a company that tunes N55s all day everyday to see their opinion and i wanted to share it.



So based on this advice I installed the NGKs I bought. The car runs amazing, it may even be smoother up top but could be placebo.

EDIT: Im not saying anyone is wrong if they dont install NGK 97506s. I'm just passing forward the advice of a professional that works with and tunes these cars every day for a living.

[shaneguags]

power cut is certainly a misfire, super knocking usually is AFR related. your fueling is probably messed up. I'd check your fuel pumps, injectors, and spark plugs.

[thermal]

Ok so I got an upgraded fuel pump now, wanted to log a pull to send to bootmod3 support and when i did, i still felt the power cut, not as bad, but still there and you can see it in the log:
https://www.bootmod3.net/log?id=63a2...729bee40248432

So far bootmod3 support says that the fueling issue is now solved and the log looks clean, and i am now waiting on their response regarding the current power cut issue. I ordered new coils just in case that may be the issue, but otherwise im not too sure.
I am going to also log a stage 1 pull to see if any differences occur.

[shaneguags]

Originally Posted by thermal

Ok so I got an upgraded fuel pump now, wanted to log a pull to send to bootmod3 support and when i did, i still felt the power cut, not as bad, but still there and you can see it in the log:
https://www.bootmod3.net/log?id=63a2171aae729bee40248432

So far bootmod3 support says that the fueling issue is now solved and the log looks clean, and i am now waiting on their response regarding the current power cut issue. I ordered new coils just in case that may be the issue, but otherwise im not too sure.
I am going to also log a stage 1 pull to see if any differences occur.

are you custom tuned ?

[thermal]

Originally Posted by shaneguags

are you custom tuned ?

no just bootmod3 stage2+

[shaneguags]

Originally Posted by thermal

no just bootmod3 stage2+

damn, well if the issue is fixed I’d clear codes and reset adaptations. if it comes back, then I would just see if bootmod3 has a solution

[Big.Al]

Any updates on this issue? On a similar boat, but on stage 2 91 map. Hpfp pressure drops around 5400 rpm way below target. However stock map car pulls fine and going to upgrade my hpfp soon as that seems to be the culprit.

[thermal]

Originally Posted by Big.Al

Any updates on this issue? On a similar boat, but on stage 2 91 map. Hpfp pressure drops around 5400 rpm way below target. However stock map car pulls fine and going to upgrade my hpfp soon as that seems to be the culprit.

yes, I have upgraded my fuel pump to dorch and logs show that the fuel pump is now keeping up (https://www.bootmod3.net/log?id=63d9...729b91d05f1d9a)

I also have replaced, coils,spark plugs(oem/oem gap) and injectors but am still getting a small stutter during wot. Way better than a power cut like I was getting, but still annoying. I've ordered some NGK SILZKBR8D8S (97506) and going to gap them to 0.023". Will update you later in the week and see if the new plugs did the trick

[Big.Al]

Originally Posted by thermal

yes, I have upgraded my fuel pump to dorch and logs show that the fuel pump is now keeping up (https://www.bootmod3.net/log?id=63d9...729b91d05f1d9a)

I also have replaced, coils,spark plugs(oem/oem gap) and injectors but am still getting a small stutter during wot. Way better than a power cut like I was getting, but still annoying. I've ordered some NGK SILZKBR8D8S (97506) and going to gap them to 0.023". Will update you later in the week and see if the new plugs did the trick

Thats good, when I sent over my logs to halim he was thinking it could be the lpfp for some reason even tho on my log the hpfp dips like crazy. Gonna order either a dorch stage 2 or just replace with an oem unit soon for the meantime.

Logs:
https://www.bootmod3.net/log?id=63aa...90c668787e682d

https://www.bootmod3.net/log?id=63aa...90c668787e6832

[designatedposter]

Originally Posted by thermal

yes, I have upgraded my fuel pump to dorch and logs show that the fuel pump is now keeping up (https://www.bootmod3.net/log?id=63d9...729b91d05f1d9a)

I also have replaced, coils,spark plugs(oem/oem gap) and injectors but am still getting a small stutter during wot. Way better than a power cut like I was getting, but still annoying. I've ordered some NGK SILZKBR8D8S (97506) and going to gap them to 0.023". Will update you later in the week and see if the new plugs did the trick

send the log to PTF, the stutter may be the effect of the sharp throttle closure at 5200rpm, which is to control the overboost ~2psi. i myself also experience overboost on the multimap stage 2+.

[Mr_M//]

This exact thing happened to me 2 summers ago, my car was running perfect. until I replaced the Turbo to ps2 (without upgrading the HPFP) and I replaced the plugs to NGK gapped .020. running stage 2 E30. then back to stage 2 ( still didn’t fix it).
I searched to resolve it,but with no confirmed answer. Some say spark plugs and others say coils or HPFP.
What I did to temporary fix the issue and also to confirm it was fuel related or if the plugged too small/ bad plugs.
. I add VP octane booster to the tank so I get easier sparks and I thought with race gas the car can run little leaner, that totally worked.
Luckily after I changed the HPFP to Dorch stage 2 problem was fixed.

[designatedposter]

Originally Posted by Mr_M//

This exact thing happened to me 2 summers ago, my car was running perfect. until I replaced the Turbo to ps2 (without upgrading the HPFP) and I replaced the plugs to NGK gapped .020. running stage 2 E30. then back to stage 2 ( still didn’t fix it).
I searched to resolve it,but with no confirmed answer. Some say spark plugs and others say coils or HPFP.
What I did to temporary fix the issue and also to confirm it was fuel related or if the plugged too small/ bad plugs.
. I add VP octane booster to the tank so I get easier sparks and I thought with race gas the car can run little leaner, that totally worked.
Luckily after I changed the HPFP to Dorch stage 2 problem was fixed.

octane booster doesn't make an easier spark, but if it worked, then your issue was most likely pinging / pre-detonation which resulted in the car protecting itself with significant timing retardation and maybe throttle closures.
OR
maybe it was unrelated at all since your real solution was an upgraded HPFP, which means you were likely having misfires due to low fuel pressure.

[Mr_M//]

Originally Posted by designatedposter

octane booster doesn't make an easier spark, but if it worked, then your issue was most likely pinging / pre-detonation which resulted in the car protecting itself with significant timing retardation and maybe throttle closures.
OR
maybe it was unrelated at all since your real solution was an upgraded HPFP, which means you were likely having misfires due to low fuel pressure.

Yeah I guess misfires due to low fuel pressure, but it worked

[Westersund]

Had this problem after my M2 was tuned last summer by a friend, got massive misfires after I collected the car but those went away after I changed to new BMW spark plugs. However the hesitation after 5K rpm remained. What I noticed while pushing the car without the engine insulation installed (after the spark plug change) I could literally hear the fuel rail getting sucked dry when the hesitation started. I strongly think that the stock LPFP, in some cases, can't even support a stage 1 tune if you beat on it. Pulling a couple of gears sure but not constantly. The HPFP can only supply sufficient pressure if the LPFP can deliver enough fuel, my belief is that the LPFP is the main restriction not the HPFP. If you stick to a stage 1/2 tune that is (Under 450 hp but with supporting mods).