Fans come on, Fuel Trims drop from 125% - 70%

[TurboGeoff]

Got a small problem, maybe some of you have had this problem before, the car idles perfectly with o2 trims of about 125%, but as soon as the fans come on, the o2 trims drop to ~70%. Any ideas what this is from? It also sometimes will randomly just not start.

-Geoff

 

[WhiteTsiAwd]

Well there is no O2 trim. There fuel trims and an O2 voltage. A lot of these cars act weird when the fans come on but your fuel trims shouldnt change. And if you mean that your fuel trims change from 125-70 then there is a big ass problem. That should not happen. but as for an answer, I dont know. Sorry.

 

[TurboGeoff]

There is an O2 trim buddy, its called FT02, its the trim that changes based on o2 voltage value. Please dont respond if you dont know your head from your ass.

 

[LousyDriver]

The FTO2 is the short-term fuel trim, and changes with the O2 reading. It is normal for it to bounce from one end of the spectrum to the other, just like it is normal for the o2 voltage to go from 0 to 1.0. When most people talk about fuel trims they only talk about the long term fuel trims. FLTL, FLTM, FLTH, which is probably the reason for the confusion. It may just be a coincidence that the fan comes on at the same time. Don't worry about it. And try not to be such a jerk.

 

[TurboGeoff]

Its no coincidence, when the fans come on, the stft goes down, when they go off, the stft goes up. Im wondering if it has to do with electronic draw and the change in voltage.

 

[WhiteTsiAwd]

There is an O2 trim buddy, its called FT02, its the trim that changes based on o2 voltage value. Please dont respond if you dont know your head from your ass.

Ok there is but how many people do you know that call it that? Hardly any. It is most commonly refered to as FTLT like Lousy said. So no need to be an ass.

 

[90 GSX]

It's an old thread, but I found it searching. Try putting your aircan back on... i can almost garuntee that's the problem.