Ability to disable Ego Corr below certain AFR (failsafe)

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dnz
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Ability to disable Ego Corr below certain AFR (failsafe)

Post by dnz »

Current running a Microsquirt with MS2/Extra and have had the following scenario run through my head.

If there was an issue with the CLT sensor for example and it was unplugged, the microsquirt reads this as 85C from memory allowing the engine to run (assuming it's warmed up).
If however, there was an issue with the wideband either completely failing (no output) or giving false readings (too high or too low) there is nothing that can be done when in the middle of nowhere if you are unable to change any settings with a laptop/phone. In this case the EGO correction would eventually max out at either + or - it's max authority depending on the 'reading'.

The idea would be that if you suspect an issue with the WB you could unplug either the signal wire from the WB controller to ECU (giving 0V reading, say 7.5:1) or unplugging the power to the WB controller itself (again 0V signal). Then under EGO settings there can be a condition that reads along the signs of 'Active above AFR'.

I have a feeling I have seen this setting on MS3 setting screenshots posted in the past but am unsure.

Unless this is already possible and I am blind, is there any reason it couldn't be implemented?
dnz
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Re: Ability to disable Ego Corr below certain AFR (failsafe)

Post by dnz »

Any thoughts?
ashford
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Re: Ability to disable Ego Corr below certain AFR (failsafe)

Post by ashford »

are you talking about this?
ego.png
dnz
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Re: Ability to disable Ego Corr below certain AFR (failsafe)

Post by dnz »

Yes exactly. Below is what is currently available.
dnz
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Re: Ability to disable Ego Corr below certain AFR (failsafe)

Post by dnz »

Just to bring this up again, can anyone give some feedback if this would be useful to have or not?
I couldn't see any downsides but I may be missing something?
Matt Cramer
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Re: Ability to disable Ego Corr below certain AFR (failsafe)

Post by Matt Cramer »

dnz wrote:Just to bring this up again, can anyone give some feedback if this would be useful to have or not?
I couldn't see any downsides but I may be missing something?
It is now in the 1.4.0 code.
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Alfagta
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Re: Ability to disable Ego Corr below certain AFR (failsafe)

Post by Alfagta »

Matt Cramer wrote:
dnz wrote:Just to bring this up again, can anyone give some feedback if this would be useful to have or not?
I couldn't see any downsides but I may be missing something?
It is now in the 1.4.0 code.
He is talking about MS2
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piledriver
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Re: Ability to disable Ego Corr below certain AFR (failsafe)

Post by piledriver »

I can confirm that if your WB sensor/controller craps out on MS2e, you may currently either need to have your laptop to turn EGO off or call a towtruck.
(or have a nice tight VE table and keep the EGO authority cranked down to <~10%)

It works as you would hope on MS3 with current firmware.
You can probably even set a check engine light if its out to lunch.
Always doing things the hard way, MS2 sequential w/ v1.01 mainboard, LS2 coils. 80 mile/day commuter status.
BigLou240sx
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Re: Ability to disable Ego Corr below certain AFR (failsafe)

Post by BigLou240sx »

I'll add my vote that it certainly would be a useful feature if the implementation is possible.

I ran into some issues in overheating the o2 sensor (and causing it to report full rich for my innovate lc1) during a drift event and saw first hand how quickly things go out of wack with no failsafe on the wb input. Luckily, the sensor cooled down after a fairly short power cycle, but would be stranded (or in for a very hectic ride home) if this were a hard failure without a way to update the msq at that moment.

I likely have a workaround in that the lc1 allows you to set the fall back afr (so instead of reported 8.2:1, it can report 13.5) which would likely allow me to drive anywhere without too much hassle.
1990 Nissan 240sx / SOHC KA-T / DIYPNP
dnz
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Re: Ability to disable Ego Corr below certain AFR (failsafe)

Post by dnz »

BigLou240sx wrote: I likely have a workaround in that the lc1 allows you to set the fall back afr (so instead of reported 8.2:1, it can report 13.5) which would likely allow me to drive anywhere without too much hassle.
The thing about reporting 13.5:1 continually is that unless your afr target table is 13.5 everywhere it will still sit at the authority limit as it will creep to it (ie. if your target is 13.7 and it keeps reporting 13.5 it will keep reducing fuel until it reaches the limit). So in that case you are in no different position to it reporting 8.2:1 or whatever it may be if the sensor failed without the lc1 fall back.
BigLou240sx
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Re: Ability to disable Ego Corr below certain AFR (failsafe)

Post by BigLou240sx »

dnz wrote:
BigLou240sx wrote: I likely have a workaround in that the lc1 allows you to set the fall back afr (so instead of reported 8.2:1, it can report 13.5) which would likely allow me to drive anywhere without too much hassle.
The thing about reporting 13.5:1 continually is that unless your afr target table is 13.5 everywhere it will still sit at the authority limit as it will creep to it (ie. if your target is 13.7 and it keeps reporting 13.5 it will keep reducing fuel until it reaches the limit). So in that case you are in no different position to it reporting 8.2:1 or whatever it may be if the sensor failed without the lc1 fall back.
Ah, good point. Setting to 13.5 for failsafe would save my idle, but be pretty wrong for a lot of the other fueling conditions on my car.
1990 Nissan 240sx / SOHC KA-T / DIYPNP
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