[ayyy]

Hey all,

08 335xi E92 MHD stage 1 93 octane with ER charge pipe, HKS bov, DCI, PE mod, recently changed .022 NGK plugs.

Happened to run some codes recently on my tablet using MHD and got the following:

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- DME active codes -
2DED - DME: Power management, closed-circuit current violation. (EXPLAINED: left my OBDII cable plugged into the tablet overnight, drew lots of current, had to reset date/time)

- DME shadow (inactive) codes -
2F6C - DME: Exhaust-gas flap, activation. (EXPLAINED: I have had the exhaust vacuum actuator unplugged in my trunk for forever, no worries here)
30EF - DME: Superknocking, cylinder 3.

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I have looked online and it seems like literally no one ever has gotten this code. When you search 30EF online google thinks you mean 30FE which is a very common overboosting code.

It's a DME shadow code, so my gut tells me that it's not of great concern, and no check engine light, limp mode warning, or notification of any kind comes on along with the code. However, "superknocking" just sounds hilariously scary to me.

I've cleared the code and will do some pulls tomorrow to test. I might just be paranoid but I feel that I have experienced a loss in power recently, however it hit 90ºF today with IATs of 120ºF so that could explain it.

Please help!

[Sgop335]

It probably has large timing corrections...may be exceeding 6

[ayyy]

Originally Posted by Sgop335

It probably has large timing corrections...may be exceeding 6

Good point, I hope it's as simple as that. Still weird that I couldn't find literally any info on the code online, aside from one master list of codes ordered by cylinder number with the description "glow ignition."

But as long as it stays a shadow code I guess I won't worry too much. Unless anyone else has any expertise to share!

[Sgop335]

Originally Posted by ayyy

Good point, I hope it's as simple as that. Still weird that I couldn't find literally any info on the code online, aside from one master list of codes ordered by cylinder number with the description "glow ignition."

But as long as it stays a shadow code I guess I won't worry too much. Unless anyone else has any expertise to share!

well it is a precursor to knock, which is not trivial. So i would not ignore the shadow code. Your boost/iat combo is way too high for your octane. Needs better octane! and good fmic.

[ayyy]

Originally Posted by Sgop335

well it is a precursor to knock, which is not trivial. So i would not ignore the shadow code. Your boost/iat combo is way too high for your octane. Needs better octane! and good fmic.

Trying to go FBO asap so yeah an upgraded IC and catless DPs are coming soon. Perhaps it's just the hot weather and high IATs that are doing it then. I only ever fill up with Sunoco or Shell 93 oct, but maybe I had some bad fuel recently or something.

As I said, I cleared it and will keep an eye out for anything these next few days and go from there. And thanks for your replies!

[Tangent]

I had the 30F2 shadow code myself about a month back which is the same thing but on cylinder 6. Right about then I also started getting a code for the bank 2 O2 sensor. (Signal stuck rich) Once I replaced both upstream sensors neither code has come back.

[ayyy]

Originally Posted by Tangent

I had the 30F2 shadow code myself about a month back which is the same thing but on cylinder 6. Right about then I also started getting a code for the bank 2 O2 sensor. (Signal stuck rich) Once I replaced both upstream sensors neither code has come back.

Thanks for the reply. Do you think it's possible that because I sometimes randomly get VERY inaccurate AFR readings (in the 200s) that this could be happening with mine? Faulty O2 sensor on its way out? Or probably not since the upstream sensor is still after the exhaust manifold?

[Tangent]

It's certainly possible. If the upstream sensor isn't giving accurate readings those wacky outputs would account for the problems. Your engine could be running perfectly fine, then that O2 sensor flips out, declares that bank to be way too rich even though it isn't and you get the screwy AFRs and knocking because it's actually running lean now.

[ayyy]

Originally Posted by Tangent

It's certainly possible. If the upstream sensor isn't giving accurate readings those wacky outputs would account for the problems. Your engine could be running perfectly fine, then that O2 sensor flips out, declares that bank to be way too rich even though it isn't and you get the screwy AFRs and knocking because it's actually running lean now.

Hmmm very interesting. Any way to diagnose bad O2 sensors aside from buying new ones and running them for a while? I realized that I have both bank 1 and 2 AFR gauges and when one reads wacky the other does too, so do you think that would mean both upstream O2 sensors somehow managed to go at the same time?

EDIT: noticed this morning that my AFR values spike (to 200s and stick there) ONLY upon sharp decel. Guaranteed this has something to do with my burble setting in MHD which is set to max aggressiveness. So, even though the value obviously isn't right, I'm sure it's set off by the basically liquid fuel moving through the exhaust manifold/turbine housing/downpipes and even igniting inside of them. So the O2 sensors may be working "okay" after all?

EDIT 2: okay yep, saw another post where someone was experiencing 200+ AFR readings after letting off the throttle with no other pedal input: "It's deceleration fuel cut. No fuel is injected so it's infinite AFR. 200 is just the highest value it displays. Pretty much all cars since about 1975 do this, if not, earlier." So I guess those readings are indeed "normal" especially with my burble settings