I just analyzed some data I logged last night from my stock 2002 Z06 and here is what I found.

Cruising around town slowly through the gears my cruising cells (0-17) averaged out to the following:


Cruising at 55-75 on the highway my cruising cells (0-17) averaged out to the following:


B1 is running leaner and is getting more fuel than B2


I blasted WOT through the gears and got the following for Cell 22


B1 is getting more fuel than B2, just like closed loop. B1 O2 readings look richer than the B2 O2 readings.


Here is an average of that blast


Average LTFT B1 is sending more fuel than average LTFT B2. Average B1 O2 readings are richer than average B2 O2 readings. LTFT values definitely seem to have an effect on WOT PE.

 

Damn! I'm still learning here so could someone explain what this means? I have perused SEFI tech books on the vette but I'm not familiar with all the abbreviations...

Sorry for being an idiot on this one but I want to learn this stuff... :confused: :yesnod:


[Modified by Bertrand, 12:12 PM 8/9/2002]

 

:lol: :yesnod:

 

FTC = Fuel Trim Cell
RPM = Engine RPM
O2 B1S1 = Oxygen Sensor Bank 1 Sensor 1 voltage
O2 B2S1 = Oxygen Sensor Bank 2 Sensor 1 voltage
LTFT B1 = Long Term Fuel Trim Bank 1
LTFT B2 = Long Term Fuel Trim Bank 2

You should read up on how the LTFT and STFT values work. Start here:
http://www.vetteguru.com/mods/howto/
http://www.cee5forum.com/diy/ltft.php


Change cee5 to c5 in the above address

Please note that the trim cells listed in the above pages are wrong. For the correct 2002 Z06 trim cells read here:
http://forums.corvetteforum.com/zerothread?id=359147


I basically log data with AutoTap and then import the data into Microsoft Access. I then run queries on the data in MS Access to see what is going on. I zipped up and posted an Access 2000 Database containing 5 logs from last night. You can download it in zipped format here:

http://www.rbartick.com/cf/rb_aug08.zip

Unzip it and open the Database with Access 2000. Go to the table tab and you will see 5 tables. These table are 5 raw data logs. They are:

Tables
1-AUG08_9s
This is my first drive of the night. It is a slow run on a light controlled road. I went WOT once at low RPM.

2-AUG08_9n
This is my second run of the night. It was done after the car sat and got heat soaked for about an hour. You can see that my IAT temps started out very high. It was a fairly mild drive on the same light controlled road, but I did go WOT a few times at low RPM.

3-AUG08_amboy
A fairly slow run through the gears on a windy back road. No WOT

4-AUG08_18S
A Highway cruise. I went WOT a few times at low RPM.

5-AUG08_18N
A 0 - 100 MPH WOT blast, and then a few seconds of cruising.


Go to the queries tab to see some of my summations

Queries
1-9S_LTFT_Cell<18
Shows the average LTFT values for cruising cells 0-17 in Table 1 above. Used to see how accurate my MAF is at closed loop. If the MAF is inaccurate then WOT A/F ratio will be changed as well.

2-9N_LTFT_Cell<18
Shows the average LTFT values for cruising cells 0-17 in Table 2 above. Used to see how accurate my MAF is at closed loop. If the MAF is inaccurate then WOT A/F ratio will be changed as well.

3-Amboy_LTFT_Cell<18
Shows the average LTFT values for cruising cells 0-17 in Table 3 above. Used to see how accurate my MAF is at closed loop. If the MAF is inaccurate then WOT A/F ratio will be changed as well.

4-18S_LTFT_Cell<18
Shows the average LTFT values for cruising cells 0-17 in Table 4 above. Used to see how accurate my MAF is at closed loop. If the MAF is inaccurate then WOT A/F ratio will be changed as well.

5a-18N_LTFT_Cell<18
Shows the average LTFT values for cruising cells 0-17 in Table 5 above. Used to see how accurate my MAF is at closed loop. If the MAF is inaccurate then WOT A/F ratio will be changed as well.

5b-18N_Wot
Shows the WOT (Cell 22) data points for Table 5. Important parameters are shown.

5c-18N_Wot_Avg
Averages out the WOT (Cell 22) data points for Table 5. Important parameters are shown.


[Modified by rbartick, 11:57 PM 8/9/2002]

 

I forgot to mention that I do not like the Excel Template on this page. First of all it includes Idle Cells in the LTFT Average. Secondly, it bases WOT on TPS when averaging the O2 sensors at WOT. I feel that WOT should be based on Cell 22, not TPS. Cell 22 is when the PCM thinks the car is in WOT.

 

wth? What do all these cells tell me??????