modifying AFR tables??

[theMelvster6]

I think this is the most posts I've ever seen in one thread by you ICH! Without arguing too...LOL I read a lot of info and what people are doing and I was lost on this one. At least I know I'm not a complete idiot. I'm starting to understand this stuff...it takes a lot longer to do proper tuning when you are piecing together tid bits of info along with trial and error without forking out tons of cash to have someone teach you or do it for you.

[lawdog]

You are right on! The devices you were talking about earlier are ones that either interface with the temp sensor to read a colder temp or interface with the nb o2 sensor to read slightly leaner. Both are used to "trick" the ECM into adding fuel which I do not recommend! Poor solutions to proper tuning. They are pretty popular with the Harley crowd.

[theMelvster6]

Is there any benefits or even drawbacks to limiting the CL and CLL areas? Constraining them to a smaller area on the fuel maps?

Also, afrBins...How does the ecm use them? if a NB o2 is only trying to achieve 14.7 (stoich) within closed loop, what do the afrBins do? or Are they included in the fuel maps for tuning purposes when comparing WB o2 data against the afrBins to adjust the fuel cells to target each AFR cell? (for examaple running veAnalyzer in MLV)

[ich]

or even drawbacks to limiting the CL and CLL areas? Constraining them to a smaller area on the fuel maps?

what's wrong with closed loop, except that those braindead monkeys at buell were too retarded to map it correctly?

How does the ecm use them?

it doesn't. there are no afr tables.

[Sirius815]

Couldn't you just tune the cl to where you wanted it and then keep the ego correction locked into 100...? (was it ego that you could lock in - I don't have ecmspy open in front of me at the moment)

Of course that would keep the ecm from keeping afr's to what you tuned them for due to changes in temperature, humidity, etc...

[theMelvster6]

Okay, so the ecm doesn't use the afrBins, I get that. but I don't understand what Ich is saying "there are no afr tables"...it's clear there are afr tables (afrBins1 and 2) within the map file to tune the fuel values. Are they just there for reference when tuning? Or what? all I'm reading is "there are no afr tables"...

[jstav]

My understanding is that the afrBins would be more useful when using a WB sensor, and when using a NB, they would be less accurate the further away from 14.7 that you target. This is interesting:
http://www.autometer.com/tech_faq_an...x?sid=1&qid=48

[lawdog]

You are correct. The AFR Bins are for your use in tuning. The ECM stores a front and rear fuel map that instructs the ECM a certain fuel injector pulse width based on the RPM and throttle position. No AFR bins/tables in the actual ECM itself. You are changing the fuel map in the EEPROM to control the IPW.

Is there any benefits or even drawbacks to limiting the CL and CLL areas? Constraining them to a smaller area on the fuel maps?

I tightened my cl and cll areas so I could run a richer fuel mixture at idle/off idle.

The whole purpose of a nb is for emissions. To maintain the best burn for the least emissions. Manufacturers are required to meet emissions standards, 49 CFR 86. You can richer for more power, leaner for more fuel economy, but manufacturers have a difficult time trying to tune to meet noise, emissions, and fuel economy standards. Hence such a huge aftermarket for tuners. Especially for motorcycles and air-cooled engines.

[theMelvster6]

Thanks Lawdog...That is what I was trying to get to the bottom of.

Ecm functions off the fuel maps

The fuel maps are tuned off the afrBins via WB o2 sensor and datalogging (or Dyno if accessible)

Closed loop should be tuned to 14.7 (stoich) to maintain 100% afv with NB o2 input to ecm

Open loop can then be tuned to desired afr for regions outside of closed loop.

The purpose of tuning is to achieve desired efficiency, performance, stability, etc with minimal corrections learned in closed loop being applied to the fuel maps while operating in open loop.

The answer to my own question...you should leave the closed loop region of the fuel maps at 14.7 (stoich) within the correlating cells of the AFR table (afrBins)...but you can modify the values in the afr tables that correlate with the open loop region of the fuel maps...AFR tables are used for fuel map tuning purposes only and not used by the ecm.

Is the flow of this understanding correct? Thanks everyone for helping understand this.

[lawdog]

Yep.

Option 1: Turn off closed loop and run any AFR anywhere.
Option 2: Tune closed loop and closed loop learn regions at 14.7. Everything else tune to your desire.
Option 3: Modify regions, tune CL and CLL to 14.7. Everything else to your desire.

I use an excel spreadsheet to tune but from your description it sounds like the software is comparing the target AFR that you want with datalogged data to calculate a change for the EEPROM or even the corrected IPW.

The fuel table is stored in the EEPROM in hexadecimal format. You then convert from hexadecimal to decimal format which corresponds with the IPW for the front or rear cylinder. You modify, or the program you are using, modifies the IPW to control how much fuel is injected based on rpm/tps. 255 is the max based on the 8 bit limitation of our ECM. (Well not just ours technically) So 255 in the table is max fueling.

Here is one of my old open loop fueling tables to give you an idea.