I’ve never actually tested writing outside of the calibration area and seeing if MHD realizes, but what I usually do to force a long write is to check on/off the Pi Safety or 6mt Shift Bog fix as those write into the program section
Readiness - Catalyst
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Okok, thanks for reporting too, well it has to be another parameter then, or maybe a combinaison of parameters ?
Anyway I am available for new logging or new parameters.
On my car, when i tick or untick the 6mt shift bog, MHD pass from 2 minutes short flash to semi long flash (9-20 minutes or something), but long write are 40 minutes if i remember correctly?
Disconnecting rear O2s or disabling them for sure stops this annoying afr oscillation, however I have not left them disconnected long term to check for any side effects such as running rich as some claim.
Now I have heard all that no nos about disabling secondary O2s as supposedly they are also responsible for 'calibrating' primary O2s but my question is that has this been proven and documented anywhere? Or just a myth circulating around?!
Really appreciate some enlightening feedback here if anyone has researched this subject.
Interesting, i was about to test the same two approach you raise :
- Physically unplugging rear sensors connectors in the engine bay and then disable 2C9E and 2C9F DTC in TunerPro to avoid a CEL. (Not a big fan of this method)
- Disabling them by setting "C_CONF_CAT" to 00 (are you meaning that too by disabling them?)
I thought that maybe, if rear sensor are disabled by tuning or physically unplugged, maybe the DME won't start any catalytic routines and it could get rid of the oscillation.
I also read about the calibrating thing and running rich, and running rich is exactly what i am trying to avoid.
I wonder why it will run richer since it's supposed to target AFR set in fuel tables ?
You probably wouldn't get a Cel light for disconnecting rear O2s, only codes.
Connectors are down below next to the sensors.
But you will get perfect afrs!
Probability a temporary solution for your emissions test?
We don't have emissions test here in AU however I am still very keen to have this fixed due to my OCD!
Okay, Brule from AU too, made a thread on another forum ("Single Turbo How to Remove Rear O2 sensors and Codes") and a video on YT, he said you will get an engine light with rear o2 unplugged, but i never tried yet, you didn't get a light ?
Oh yeah thanks, i just realised rear sensor connectors are under the car.
I will try the C_CONF_CAT first to see what happens.
TBH I just disconnected for a short test drive and got sensor heater activation codes only.
Maybe if keep disconnected longer would throw CEL, i don't know about that.
Yeh if you know how to disable them try that first.
I am on ots maps so no soft changes...
I wonder how much an emission would set you back if you want to try this?
Honnestly, I have no idea if the C_CONF_CAT to 00 is the way to disable rear sensor, probably not, but i will give it a try since :
"00 - limited learning, only checks front lambda sensors and assumes no rear o2 sensors."
and it's 2 minutes of map write.
What do you mean ? you mean if i want to pay for a voluntary emission test ? it's around 30$
Ah never mind, I thought you or someone mentioned they are due for emissions test so just wondered how much the financial loss if they go to the test with disconnected rear sensor and the test fails (perhaps due to out of calibration front O2s and running rich as some people claim) ...
Basically If the front O2s really go out of calibration I don't know how that can be measured and proven other than a sniffer emission test?
Yes, that was me, i failed my "MOT" due to emissions, during the MOT they verify lot of things (like braking force, security stuff, handling) including emissions (they measure lambda and CO). I failed emissions, and i have a delay to resolve my problem and try again, i have unlimited try during this delay, but it's not free, it's around 30-40$. But i guess if i ask in some MOT, a voluntary check of my emissions (outsite the MOT official protocol), they will ask me something between 20-30$ in cash or something, or a kind MOT guy could also maybe do it for free. If i can't resolve the problem in the delay, i do not have the legal right to drive the car on public road. If i get arrested, i probably get a fine, and worst case, they confiscate the vehicle.
My MOT failed due to high CO, and i think that oscillating AFR aren't helping while probably dumping useless fuel indefinitely on primary cats that do not exist anymore. Secondly, i hope i could lean a bit the fuel map too to reduce CO (I am affraid that the oscillating AFR is kind of taking over the AFR value you set in your fuel map)
Anyway, i will try the C_CAT_CONF asap and will report here, probably tomorrow.
If you're going to change C_CONF_CAT to 0, do not forget to reset "variant adaptation" in INPA. Lambda sensors are considered a variant by the dme and unfortunately MHD does not have a variant adaptation reset procedure.
This combined with disconnecting the rear o2's would be the proper way to calibrate them out
Thanks, you are right !! I was about to prepare a C_CONF_CAT set to 00 bin for today for testing, but after reading your message, i read again the post of hobbit382 where i originally read about the C_CONF_CAT :
"The dme has built in logic to run off single or dual bank O2 sensor all the way back as far as ms41. This is factory programming, no trickery involved, you just need to know how to tell it to do so. the switch to do so is C_cat_config. This tells the dme if its running single bank pre cat O2, dual bank pre cat, single bank post, dual bank post, or no post O2. On top of all that, it has a switch for self learning of the configuration. For ease of use I use the later, switch the config switch to 0, and program the vehicle. Once the programming is done, unplug the bank 2 pre cat and post cat o2 sensors. Next use inpa or ista and clear the "learned variants" in the dme. turn off the car then clear any faults stored and enjoy not roasting anymore o2 sensors. It seems most people are using the latest sw versions so ill give the address for those. for MSD80 on I8AOS its located at 428C6 in the full or 28C6 in the parital (is anyone even using the partial?) for MSD81 on IJEOS its located at 4C4A2 or C4A2 in the partial."
I assumed wrongly that i could try this solution without unplugging physically the sensors, but i guess it's not possible.
I still may give a try but probably not today, won't have the time to check my INPA laptop and unplug the sensors.
Now what did @hobbit382 mean about not roasting anymore o2 sensors?
It’s been a while now but i vaguely remember having pre-cat o2 issues that were i think solved when i unplugged my old post-cat o2’s
But yes I came from MS43 days which are also made by Siemens and used the same abbreviations and C_CONF_CAT was one of the big toggles to get forced emissions readiness
It’s been a while now but i vaguely remember having pre-cat o2 issues that were i think solved when i unplugged my old post-cat o2’s
But yes I came from MS43 days which are also made by Siemens and used the same abbreviations and C_CONF_CAT was one of the big toggles to get forced emissions readiness
Hmm i don't know, i think they were trying to find a solution for single turbo users.
I seen on a old thread you were talking about trying other value c_nr_conf_cbk_ex aka "Enable Single Rear 02", in the XDF description, they only talk about 02 (use both rear sensors) and 04 (just bank 1 rear), did you try 00 or 01 ? Maybe one of these is to disable both, i think about 00 ?
So are you saying there is already a proven proper way of disabling secondary O2s and primary afrs will be fine e.g. not going out of calibration rich or lean?
00 is not a defined value
01 is for a single bank (whatever this means)
02 is standard twin bank
03 is for no post cat o2 on bank 1
04 is for no post cat o2 on bank 2
Technically yes this would be the proper way of disabling the secondary o2's, but we have yet to see if it will stop the AFR/AFL (airfuel-rich/airfuel-lean) cycle the dme does. I'm hoping it will stop it.
Thanks.
I wonder if there is a way to apply these changes to MHD OTS maps as I dont want to go through custom tune only for these minor changes?
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