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      09-03-2022, 12:26 AM   #1
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AFR oscillation causing stft oscillation

https://www.youtube.com/shorts/ND0SmSr0mlg

A weird oscillation occurring here. Happens sometimes. Rought startup warm and cold. no codes. happens at speed too. It gets fixed whenever I enable the new mhd oscillation setting.

Is this a sign of a bad O2 sensor? Bad DP clamp?
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      09-03-2022, 01:35 AM   #2
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Quote:
Originally Posted by sliver 335 View Post
https://www.youtube.com/shorts/ND0SmSr0mlg

A weird oscillation occurring here. Happens sometimes. Rought startup warm and cold. no codes. happens at speed too. It gets fixed whenever I enable the new mhd oscillation setting.

Is this a sign of a bad O2 sensor? Bad DP clamp?
Normal behaviour. running catless DP's?

In MHD flash options make sure Aftermarket DP's is selected, then a option will show up, apply oscillation fix.
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      09-03-2022, 01:41 AM   #3
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Quote:
Originally Posted by TSilver335i View Post
Normal behaviour. running catless DP's?

In MHD flash options make sure Aftermarket DP's is selected, then a option will show up, apply oscillation fix.
that fixed the oscillation, but I am still getting studdering cold starts and warm starts. Replaced spark plugs, basically new coils. whenver car starts it runs rich almost 16 afr and it request a lot of stft.
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      09-03-2022, 06:32 AM   #4
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Quote:
Originally Posted by sliver 335 View Post
that fixed the oscillation, but I am still getting studdering cold starts and warm starts. Replaced spark plugs, basically new coils. whenver car starts it runs rich almost 16 afr and it request a lot of stft.
Have you pulled the plugs and checked to see if they are wet or smelling of fuel?

Injectors could be leaking. Also worth logging and checking HPFP on start up,
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      09-03-2022, 04:13 PM   #5
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Quote:
Originally Posted by Saif2018 View Post
Have you pulled the plugs and checked to see if they are wet or smelling of fuel?

Injectors could be leaking. Also worth logging and checking HPFP on start up,
I had indeed about 2 weeks ago, since these injectors are fairly new 5k miles index 12, I suspected there was no leak and yeah no leaks from injectors. Whenver i step on the gas, my stft goes to the roof. almost hitting 34% around 20%
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      09-04-2022, 04:52 AM   #6
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Quote:
Originally Posted by sliver 335 View Post
I had indeed about 2 weeks ago, since these injectors are fairly new 5k miles index 12, I suspected there was no leak and yeah no leaks from injectors. Whenver i step on the gas, my stft goes to the roof. almost hitting 34% around 20%
HPFP? Does it reach around 700psi straight away?

Remains above 1500psi on pull?


Is this on a custom tune or OTS map?
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      09-04-2022, 03:19 PM   #7
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Quote:
Originally Posted by Saif2018 View Post
Quote:
Originally Posted by sliver 335 View Post
I had indeed about 2 weeks ago, since these injectors are fairly new 5k miles index 12, I suspected there was no leak and yeah no leaks from injectors. Whenver i step on the gas, my stft goes to the roof. almost hitting 34% around 20%
HPFP? Does it reach around 700psi straight away?

Remains above 1500psi on pull?


Is this on a custom tune or OTS map?
YUP. hpfp is fine. no errors on hpfp. whenever i do a pull it acurally stays above 2k. on ots map for mhd. i've tried v10 and v9 and v8. same issues. issue also occur when i flash to stage 0 on mhd too
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      09-04-2022, 03:47 PM   #8
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My car had an issue with STFT's maxing out on one bank and it was the O2 sensors.
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      09-04-2022, 03:51 PM   #9
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Quote:
Originally Posted by whyzee125 View Post
My car had an issue with STFT's maxing out on one bank and it was the O2 sensors.
can mine be bad in both banks? My stft aren't maxing out but they are hitting 20s on a pull. and they are both around 20% on a pull. they are almost 100k mile o2 sensors so im guessing they both are bad already. Issue with my car is that it starts up too rich. it requests too much stft. aswell as doing a pull it req too much stft. my hpfp sits around 2200 psi during a pull at high rpm.
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      09-04-2022, 04:31 PM   #10
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It's a little odd for both to go bad at once but I've seen weirder things. Could also be something like the front ones throwing the AFR out of whack, etc. Doing all 4 would probably be a good idea with 100k miles
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      09-04-2022, 05:33 PM   #11
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Quote:
Originally Posted by sliver 335 View Post
YUP. hpfp is fine. no errors on hpfp. whenever i do a pull it acurally stays above 2k. on ots map for mhd. i've tried v10 and v9 and v8. same issues. issue also occur when i flash to stage 0 on mhd too
Could be your O2 sensors, as stated by others probably a good idea to do them all at your mileage
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      09-04-2022, 10:56 PM   #12
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Quote:
Originally Posted by Saif2018 View Post
Quote:
Originally Posted by sliver 335 View Post
YUP. hpfp is fine. no errors on hpfp. whenever i do a pull it acurally stays above 2k. on ots map for mhd. i've tried v10 and v9 and v8. same issues. issue also occur when i flash to stage 0 on mhd too
Could be your O2 sensors, as stated by others probably a good idea to do them all at your mileage
yeah I have bought all 4 oem boshe ones (holy crap they are expensive). by any chance do you know how to remove the rear one that is on top? Or do i have to drop one of the DP down?
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      09-05-2022, 12:20 AM   #13
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Quote:
Originally Posted by sliver 335 View Post
yeah I have bought all 4 oem boshe ones (holy crap they are expensive). by any chance do you know how to remove the rear one that is on top? Or do i have to drop one of the DP down?
VRSF DP's right? I've done without removing DP's Undoing it is easy you can get on the rear one using an open end spanner up between the pipes. Now installing new one is more difficult to get started by hand.
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      09-06-2022, 02:45 PM   #14
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Quote:
Originally Posted by sliver 335 View Post
that fixed the oscillation, but I am still getting studdering cold starts and warm starts. Replaced spark plugs, basically new coils. whenver car starts it runs rich almost 16 afr and it request a lot of stft.
16:1 is not rich. It is the exact opposite. That is lean.
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      09-06-2022, 02:46 PM   #15
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Do you have inpa? Check O2 voltage during startup.
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      09-09-2022, 08:51 AM   #16
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Quote:
Originally Posted by Dave92N54 View Post
Do you have inpa? Check O2 voltage during startup.
didn't check inpa. but yesterday I had received some o2 sensor codes for activation and stuff like that
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      09-09-2022, 08:52 AM   #17
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Quote:
Originally Posted by sliver 335 View Post
Quote:
Originally Posted by Dave92N54 View Post
Do you have inpa? Check O2 voltage during startup.
didn't check inpa. but yesterday I had received some o2 sensor codes for activation and stuff like that
Sounds about right.

What codes?
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      09-09-2022, 03:14 PM   #18
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Quote:
Originally Posted by Dave92N54 View Post
Quote:
Originally Posted by sliver 335 View Post
Quote:
Originally Posted by Dave92N54 View Post
Do you have inpa? Check O2 voltage during startup.
didn't check inpa. but yesterday I had received some o2 sensor codes for activation and stuff like that
Sounds about right.

What codes?
2C9D
2CA7
2CAB

are the three codes
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      Yesterday, 09:16 PM   #19
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Ever figure this out op? I'm having same codes and have exhausted almost all possible issues except it being software related.
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      Today, 09:09 AM   #20
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Quote:
Originally Posted by gunnerbourne View Post
Ever figure this out op? I'm having same codes and have exhausted almost all possible issues except it being software related.
Have you replaced the O2 sensors and MAP sensors in chargepipe and intake manifold?

I’m not sure if the MHD O2 sensor oscillation flash option would be of any use in this case?
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