Fuel Trims...

[JiP]

Who knows a lot about fuel trims and o2?

I put my stock air filter back and my o2s were normal at idle, at wot was totally lean, makes no sense becuae with my K&N shortram i was running really rich. I reset the ecu (pulled neg bat cable), and now o2s are normal again, but datalogger shows 17% short fuel trim, and at partial throttle long and short are in the upper 10%. Is this because I reset? Cause otherwise my cars dumping fuel like crazy.

[pinoyesv6]

did u give the electronics a chance to relearn everything b4 hooking up the datalogger?

[JiP]

<div class='quotetop'>QUOTE(PinoyESV6)</div><div class='quotemain'>did u give the electronics a chance to relearn everything b4 hooking up the datalogger?</div>

Of course not I drove for 5 min until it was warm and plugged in...I just like to panic right away :roll: https://www.thegalantcenter.org/style_emoticons/default/biggrin.gif

I get very scared seein 16% dumps if you been reading my posts I get like 10mpg for the past few months. The other day put the stock box back and new copper plugs and I was up to 24mpg again. Until I reset the ecu today and boom sucking fuel again..for today atleast.

Do you know how many trips or driving time it takes for the ecu to be "learned" or is it just a random thing?

[IllestGalant]

you have to be careful with fuel trim. if it is adding fuel this is making the fuel richer. the fuel trim is adding fuel because there is a lean condition, not a rich one. You must find out what is causing your car to run lean.
Usually means a loss of fuel. How many miles on the car? How is fuel pressure? when was the last time you changed your fuel filter and can you blow through the filter, is it clogged? are your injectors dirty or clogged? How is fuel pump voltage? Is the fuel pressure regulator leaking, does the fuel pressure regulator vacum hose smell like fuel?
those are usually the cause :shock: