fuel trims adjustment with SafcII

[talon14turbo]

My fuel trims are driving me crazy. I have a wideband a/f gauge that reads lean at idle and cruising speeds. If I tested WOT it reads rich between 10.1- 11.1 depending on my afc settings. I'm confused because if I add fuel using the SAFCII I would start to see that A/F gauge start to register at around +20 or more but my stft's would start to run in the neg numbers (i.e -14 or more). When I lean the SAFCII to around -3 or so my stft's & ltft's would show 0 - +3 on the logger but my wideband would not register because it is lean. Any help would be appreciated.

 

[wimploki]

When was the last time you check for boost leak or maintenance? Whats the condition of your spark plugs, plug wires, etc...? Heck, your front o2 sensor might be kicking the bucket soon.

If your wideband is properly installed and w/ a good working wbo2 sensor, i would trust the wideband reading over your logger. Then again, having boost leak issues can throw off your readings.

After making adjustments to your safc ii w/ the aid of your wideband, give it some time for your ecu reading to recalibrate itself.

Good luck

 

[JayRolla]

To get a good 14.7 at idle I had to add alot of fuel. At the 1000rpm mark Im at about +30%. At the 1800rpm mark im at +10%. Get the wbo2 reading 14.7 while cruising and then reset the ecu. Let it readjust and see what happens.

 

[matthewdesigns]

I just got back on the road with my Keydiver/SAFC setup after being down for a few months, and was having issues with the setup. On the advice of Jeff, I reset my afc to 0 across both lo and hi ranges, and logged my LTFT's. He suggested setting the LTFT's by way of fuel pressure rather than afc adjustment. Said it's like matching the injectors and fuel pump to the chip. My LTFT's happened to be right at 0 after I rezeroed my safc and drove at a cruise for a few minutes. Confirmed it by driving another 30 minutes at a steady 55mph and they never changed, though my cruising afr was around 13.8:1 which is a little rich. I can see this technique being OK unless you are more than 3-4psi away from stock (43.5psi for a 2g). Then I'd start to question other things, like big intake leaks and bad narrow or WB o2 sensor as suggested already. He then said to adjust my STFT's with the safc.

Before I did this I was all over the place with my afc trying to correct the idle vs. WOT vs. part throttle and was not satisfied with any setting. I was about to order a reburned chip from him to make the large (+14) corrections instead of the afc. Right now I'm on the pump 91 image (pump91/e85 dual image chip), at 23psi, +4 correction at WOT above 4Krpm, and -1 at idle, and only the occasional count or two of knock. Afr's drop to 10.7:1 against a target of 10.5:1 at WOT, and idle is ~15:1.

Hopefully this will help you get straightened out.