Has anybody modified this table in getting to help get AFR's to 14.7 during cruise? Im trying to get to a decent AFR during cruise .. Is this the right table to use?

Right now .. with "factory" table .. I run 13.2-13.4 AFRs BLMs are pretty much on the money.

I have started to lower the #'s in the table and its getting better but seem to find a few odd things going on with the ECM.

During low rpm/high load conditions the WB is reading 13.2's and the ECM is adding as much fuel as possble? So do I pull the #'s even more down in that MAP range?

I cant find any reference stuff ... so any leads/suggestions would be appreciated.

Rick

 

There are 3 tables that need to be changed. Typically they are set up as high, low, and center values. See the Tuning Guide sticky for a link under the '8746/'8063/'7747 ECM chapter about 'fueling.' This explains the O2 window operation.

At low RPM & high MAP the ECM may be in PE mode. Is the commanded AFR still 14.7:1?

RBob.

 

You can also check out a thread that that I made a spreadsheet for making the adjustments easier. The concept was to increase the tables by 100mV and then have the "coolant" modifier table subtract out the 100mV added to the others. (This maintains the stock settings)
Then by only adjusting the values in the coolant table, you could shift the windows/ranges together. Its about 1/2 way down the thread. Has the stuff graphed out so you can see what is being adjusted.
Do a quick search on "how to command a richer A/F in CL?"

 

Not in PE mode.. I had made sure of that ... the commanded AFR is 14.69

Rick

 

So "reversing" this can "lean" out the motor???

Rick

 

You can go richer or leaner with this method by adjusting the only the "coolant table".
The coolant table can only subtract from the o2 table values.
By adding 100 to the o2 tables, they are richer but the 100 being sub'd out by the coolant table makes it equal the stock setting.

Adjusting the coolant table to "50's will make the tables 50 mV higher.
Adjusting the coolant table to "100"s makes stock settings
Adjusting the coolant table to "150"s makes the tables 50mV lower.
This only works if you have added the 100 to the other tables first.

I sugest only 25 to 40 mV adjustments until you confirm the reaction and then fine tune at 5mV or less increments from there.
Added link from other thread. Couldn't do it before for some reason.
http://www.wideopenwest.com\~Johnand..._TABLES_8D.xls

Edit: make sure to confirm you add 100 to the coolant table values. My sheet shows "0" for all the original coolant table entries for AUJP. Other bins have values in the table that "If" doing this mod should have the 100 mV added to them and not just use the 100 value.

 

Thank ya!

Rick

 

Edit: Nevermind.. figured it out.

 

[Sorry for bringing back from the dead, but I'm finally running again and just got a chance to play with this]

Thanks for the info, easy enough to understand.. A couple notes:

1) The Coolant table listed in the sheet and XDF don't really MATCH the source code. The table is acually 14 cells (not 9) and referenced to coolant temps, not MAP values. By missing the top 5 cells, these changes will not work correctly with higher coolant temps.

2) You're doing an offset of mV in the Coolant table, when it's actually "counts" that are being stored. I finally figured out that you're converting counts to mV to equate to the O2 tables which makes sense when folks are actually modifying them using the XDF. (It's only confusing for folks that try to add 100 counts to the coolant table after reading the source and finding the O2 sensor pegged at 0.040mV for the entire test drive.. :-( )

Thanks again!