Using the FA Stoich and FA Stoich Even and Odd tables we can set a desired FA ratio. This works fine for open loop conditions, but it seems like closed loop always targets 14.7 AFR or .068 FA regardless of what the requested FA ratio is at that time. Has anyone found a way to adjust the target points for closed loop conditions for the modern Hemi engines.
Its actually not commanding 14.7, the scanner just translates the commanded ratio, whatever you put into the tune to be lambda of 1, then when you ask it to convert to gasoline itll just show 14.7.Originally Posted by mxatunerjg
Think of it as you are redefining stoich before any translation, you are saying ok make lambda of 1.0 be 14.5 AFR. then you go to log and you log 1.0, kind of pointless. I just create a custom math that is whatever stoich value I really want, and use that in my error math for commanded versus actual. If you ever got down to the nitty gritty in the log, you will see your fuel trims go to 0% right around whatever commanded stoich you actually input.
Let me try to re-explain that. If I set a FA Stoich in the tune to say .0769 or approximately 13.0 AFR....our dyno still says it is idling at approximately 14.7 AFR even though the log is showing a target of .0769 FA. If I watch the STFT and LTFT it also zeros out around the point where our dyno is reading 14.7 AFR. Not really a scanner issue as much as it doesn't seem like my commanded fuel is actually being applied in closed loop.
is NN still on? not sure those settings do anything with it still on.
I've tried it both ways. Currently I am tuning a 2012 Charger with NN off. I made an attempt to try it on this car last week just to see what happened. No luck
This ended up being a wideband sensor issue, had two wideband sensors going out at the same time. Found it when the sensors were very slow to react during large throttle movements, replaced the sensors and all of a sudden here we sit idling at 14.0. Exactly as commanded.
Do you have closed loop completely disabled? If not, I'm surprised that the trims didn't bring the lambda back to 1 (14.7:1) regardless of what's in that table as the narrowband sensors used for closed loop are only capable of reading between about 14.6:1 and 14.8:1 and can only be used in closed loop to target 14.7:1.
Or am I not understanding how the closed loop works with these ECUs?
closed loop brings it back to stoich for whatever is in the tank, not just 14.7
the FA ratio in my 2014 Wrangler is set for stoich at 14.1 so that Stoich in the tune matches stoich for E10, which is more than likely what will be in the tank.
this is to keep fuel trims close to 0 due to fuel type.
this does not mean you can edit this value and idle or run richer or leaner (in closed loop). fuel trims will still correct back to stoich for whatever is in the tank.
couple this with variations in wideband controller reporting/conversions from lambda to AFR and you can really confuse yourself when you are in closed loop.
my advice is to tune your car in open loop with a wideband reporting lambda (do not use AFR). When you are done and go back to closed loop, set your stoich table for whatever is in the tank. 14.1 for E10, 14.7 for E0, 9.85 for E85, etc)
there are 2 enable\disable switches for closed loop
1) Engine>Fule>Open & close loop> close loop enable
coolant temp ( above which closed loop will be enabled) => keep it as it is if you want your afr 14.7:1 at ideal
2)Engine>Fule>Open & close loop> close loop enable
ECT rear (must be above this to enable closed loop fule for rear O2) =>try to max this value and disable O2 S2B1 and O2 S2B2
Higgs Bosun is correct.
Some are kidding themselves if they believe that the narrowband sensors used in closed loop will target anything but lambda 1.00
They cycle under and over lambda 1.00 and that is the limit of their capability.
You can 'command' whatever FA Stoich you like and they will trim back to lambda 1.00
So although changing FA affects OL fuelling, it really only changes fuel trims in CL.
Best to set FA stoich to the fuel type you are using and then tune the engine.
Then if you ever change fuel from gasoline to E10 etc, adjusting FA stoich changes ALL the fueling to suit.
I have no rear sensors on my hellcat and I get 02 feedback. I did have one bank get funky when I tried disabling them the first time and I selected one front and one rear because hey I was in a rush to start. So that seems off.
Ok but what if i want to run 15.4 AFR(0,0650) for economy...the only way i see to do that is to change the stoich...havent seen where you could switch to lambda 1,047 instated in editor.
You can't, quite simply.....unless you want to run full time open loop, i.e. no fuel corrections.
I was just replying to the 02 feedback response to Jay but Higgs is right.
Just curious but is this the Innovate DLG-1? I'm running into an issue with that device giving me horribly lean readings in my HPT, despite the car being rich. The owner recalibrated too. I'm reading 14.x, his gauge is reading mid 12's and at the dyno they read him in the 11's. It's always easy to tune with bad data.
2013 Dodge Challenger RT Plus - Shaker
Sounds like an incorrect transfer function or a bad sensor
The new innovate o2 sensor fails alot....alot!!.
Reply With Quote