mrfred

iTrader: (50)

This is for the AEM?

Drill_Sergeant

iTrader: (21)

oh yes im sorry. this is for the AEM UEGO

Danieln

iTrader: (1)

Danieln, the "x" is strictly for logging with serial cable under the "external wideband" option.

the placement for the formula you input is for the "wideband AFR" option shown here:


I just realize that after I read more of your posts.
Thanks a lot

mrfred

iTrader: (50)

You're formula is correct for an ideal analog input, but often there are ground offsets in the analog input signal. When I checked my rear O2 analog input, there was a consistent offset of around 3/255 which is approximately 0.1 AFR for my LC-1 calibration. See this post:

https://www.evolutionm.net/forums/ec...ml#post5537603

If the AFR read via the analog input is low, then add to the offset, e.g., use:

0.03913*x+10.2

If its reading high, then subtract the amount its reading high, e.g., use:

0.03913*x+9.8

Drill_Sergeant

iTrader: (21)

^^^^^^^^ thanks

mrfred

iTrader: (50)

NP. That was an easy question. :-)

Drill_Sergeant

iTrader: (21)

i'll be testing it out tomorrow

Drill_Sergeant

iTrader: (21)

mrfred what should i do if its low by 0.05?

that's about as close as i cant get to perfect?

mrfred

iTrader: (50)

Within 0.05 is pretty good, but if you're sure its consistently low by 0.05, then increase the offset by 0.05.

Drill_Sergeant

iTrader: (21)

actually looking at it sidebyside on excel, it shows its pretty dead on during idle, but when WOT it's -0.2 to -0.3

mrfred

iTrader: (50)

Assuming you did a good job grounding the AEM controller, then it sounds to me like either the calibration that AEM provides for the analog out is incorrect, or the gauge is reading incorrectly. Probably safe to assume the gauge is correct and the analog out cal is wrong.

Assuming that WOT is richer than idle, then to get the analog out to match the gauge, you need to decrease the slope (multiplication factor) slightly increase the offset a bit. If you tell me your AFRs at idle and at WOT for the guage and the analog out, I can work out the correct formula for you.

Drill_Sergeant

iTrader: (21)

how about i email you the log?


PM me for my email?

mrfred

iTrader: (50)

Not sure I have time to analyze a log. Try 0.03693*x + 10. With that slope, AFRs should be high/low by the same amount at idle and WOT. Adjust the offset to get rid of any difference.

Drill_Sergeant

iTrader: (21)

here is a small clip from the log...



also i posted a question in your logging boost thread about a P0108 code upon start ups.

hediki12

i think i may have figured out why the analog is off.. i have 2 harneses for my car so i have tons of ecu pins and looking for a pin i noticed that the wire going to the rear o2 (from the spare harness) has a plastic wrap over it. so i pealed back a little and found that the o2 wire is surrounded by insulating wire connected to a ground wire so i cut the whole thing and used it. im wondering if the insulated wire thats grounded is used to stop interference /static? like how a room with alot of copper piping will stop cell phone signals. i havent been able to test this as that i just installed it (yay) and the o2 sensor i buy is dead (fml) . so let me know your input on this.