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BMW 3-Series (E90 E92) Forum
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N54 “Superknock”
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09-29-2024, 07:24 PM | #1 |
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N54 “Superknock”
Hello! I want to start off prefacing, I am an N54 newbie. So I apologize for any stupid questions.
But I recently bought a 335i n54 and I did the classic intakes, CP, FMIC, stage 1+ MHD. 91 OCT I also installed new Endor coils and 1 step colder plugs. Today I installed catless Downpipes and flashed MHD 2+ 91 OCT Car sounds great and runs great. The issue i am having is, at WOT around 5-6k the revs stutter ever so slightly and MHD is showing a “super knock” shadow code. I cleared the code and tested multiple times. And the super knock code moves seemingly randomly between cylinders. First time it was cyl 5. Then cyl 6 and cyl 2. I flashed back to Stage 1+ it’s having the same issue. Superknock shadow code for cyl 1 this time. If I drive the car sporty, but dont go WOT to 6.5k, the car doesnt throw the Superknock code. Even when revving the car out to 6.5k at 70% throttle does not cause the code. It’s only happening WOT and high rpms. The car drives amazing, and I dont hear or feel any misfiring. Just the minor stutter in the revs and the codes so I just dont understand what’s going on |
09-29-2024, 10:19 PM | #2 |
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Flash "Stage 0" (no tune but MHD stays installed, easy and fast) then do a proper log and post the file here. We need to see your fuel pressure.
It could also be injectors, or maybe something simple as carbon build up. |
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Yesterday, 02:49 PM | #4 | |
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Thabks for the reply. Here is the request Stage 0 Log. https://datazap.me/u/es335/stage-0?log=0&data=3-21 Last edited by ESmotorsports; Yesterday at 03:18 PM.. |
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Yesterday, 02:51 PM | #5 | |
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https://datazap.me/u/es335/stage-0?log=0&data=3-21 Last edited by ESmotorsports; Yesterday at 03:19 PM.. |
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Yesterday, 08:25 PM | #7 |
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Yesterday, 11:01 PM | #8 |
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The most you can run without exceeding the capacity of your HPFP is E40 and that's assuming a perfectly healthy fuel pump and injectors. I would suggest not trying any high ethanol tunes yet until you sort this out. Even with 91 octane on stage 0 you should not see timing corrections like that.
I'm on a mobile phone and can't see all the datazap log data easily, but nothing looks too bad. Wonder what's causing those timing corrections. Have you had a walnut blast done? I have similar timing corrections even on a tank of 101 octane with Stage 0 MHD, though I have some big differences between bank 1 and bank 2 fuel trims that I'm trying to sort out. I had a walnut blast done by a reputable shop, well I paid for it at least. I had the manifold off a few weeks after and I didn't get a good look at my intake valves but they were still very black and very wet. Makes me wonder if they didn't do a walnut blast but just sprayed some solvent cleaner on them. |
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Yesterday, 11:02 PM | #9 |
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thats not a very good log, need a steady wot gear pull but with your superknock issue, kinda tough. looks a little lean with major timing corrections. as always i would baseline compression test it 1st. what are your injector index? i would pull your plug and check color
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Yesterday, 11:15 PM | #10 | |
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What do I need to do differently to improve the logs? |
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Yesterday, 11:23 PM | #11 | |
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