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      01-06-2021, 01:18 AM   #23
M3hf80
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Quote:
Originally Posted by Kilabyte View Post
^ If it's really a gas problem and you're filling up at random little gas stations and not Shell then there's your issue.
I always fill at Shell or Costco. I guess it's just CA gas? But that doesn't make sense, 95% of all F80's in CA run 91 octane and I'm the 5 percentile?
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      01-06-2021, 01:24 AM   #24
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I took your first log ...707 and isolated just the Ignition Timing 1-6 and the Knock (click on everything else in the bottom list to remove from graph). In both the 3rd gear and also the 4th gear part your cylinder 4 timing falls apart first and then other cylinders join. When the timing is pulled your 3rd gear boost peak also dips, which you may have felt as lost power. and then there was that single knock at 5611RPM.

The second log ...791 is also similar in the timing breaking up and one knock, but cylinder 2 leads the breakup and other cylinders join in your 3rd gear part, then cylinders 4 and 6 lead the breakup in the 4th gear part.

I'm thinking you have crappy gas and need to drive it all out first, then fill up with 93 at a known quality spot. Don't add ethanol, just get this possible junk tank run out. Don't push hard either, because of the knocks. I'm thinking bad gas because the timing issue affects a variety of cylinders, not 4 alone. Drive in the new gas for 10 miles and then log again same way.

If you still have problems then I would examine the plug in cylinder 4 against the others. You may have a crack in the ceramic. If you do get into this job just put in new OEMs or NGKs at 0.021" and be done with questioning plugs. If you still get problems after new plugs mark your coil #s and swap them around to the other cylinder bank and see if the problem follows one (move Coil#1-2-3 into 4-5-6, and 4-5-6 into 1-2-3, if Cyl#1 acts up instead of Cyl#4 then the problem is likely Coil#4).

I hope the gas is the quick fix!
Thank you for breaking it down! My car is at 25k miles and I'm on OEM plugs, the gas just doesn't make sense to me. There are a million M4s in CA that run the same gas if not shittier gas than me and mine's the one that knocks? Is it because I'm running more power than an average M4? There's a ton of stock F8xs in CA and run to 100k miles with absolutely no issues.
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      01-06-2021, 08:48 AM   #25
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Stuff happens at gas stations...I worked at one. Just burn off what you have and get a half tank of fresh top tier stuff. Still a prob...then you need new plugs. Tuners swap plugs out at about 15K miles.
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      01-06-2021, 11:33 AM   #26
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Stuff happens at gas stations...I worked at one. Just burn off what you have and get a half tank of fresh top tier stuff. Still a prob...then you need new plugs. Tuners swap plugs out at about 15K miles.
Is my car "knocking"? Also I flashed it to ACN91 and I still notice the loss of power.
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      01-06-2021, 02:16 PM   #27
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Is my car "knocking"? Also I flashed it to ACN91 and I still notice the loss of power.
You only had 1 knock on each log. It's your timing off causing loss of power.

Did u run out the gas and put in some fresh?
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      01-06-2021, 03:39 PM   #28
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Quote:
Originally Posted by TopJimmy View Post
You only had 1 knock on each log. It's your timing off causing loss of power.

Did u run out the gas and put in some fresh?
I was low on gas and filled up a little bit before both logs, I put in a new tank of Shell 91 and I feel like it's the same thing.
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      01-06-2021, 04:55 PM   #29
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Quote:
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Quote:
Originally Posted by TopJimmy View Post
You only had 1 knock on each log. It's your timing off causing loss of power.

Did u run out the gas and put in some fresh?
I was low on gas and filled up a little bit before both logs, I put in a new tank of Shell 91 and I feel like it's the same thing.
Log it again
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      01-07-2021, 07:54 PM   #30
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Originally Posted by M3hf80 View Post
You're onto something here, I do have traction control on 100% of the time as I foolishly flashed my MDM to GTS MDM and now that's too much slip for me so I always keep it on lol.

The traction light comes on during the pulls but I'm doing it on the same road back n forth so I was expecting the pulls to be consistent all across. I was always hesitant on pointing fingers as the gas because my car felt fine on stage 1. I did not know the car cuts power like that.
Put it in MDM mode (hit traction button once) and see how it feels.
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      01-16-2021, 08:47 PM   #31
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Swapping spark plugs this weekend, if it's still running funny, may look into a pro tune.
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      01-20-2021, 03:30 PM   #32
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Quote:
Originally Posted by TopJimmy View Post
You only had 1 knock on each log. It's your timing off causing loss of power.

Did u run out the gas and put in some fresh?
Changed the spark plugs and it runs a lot better!
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      01-20-2021, 04:03 PM   #33
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Quote:
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Quote:
Originally Posted by TopJimmy View Post
You only had 1 knock on each log. It's your timing off causing loss of power.

Did u run out the gas and put in some fresh?
Changed the spark plugs and it runs a lot better!
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