simple question, how do i know if im running rich, i mean i noticed i think that my gas milage wasent as good, i mean i only got like 240 miles to a tank of gas, how many gallon gas tank an s5 got, so what do i check to see if im running rich, and messing with the idle screw on the intake, would that make it run rich, i mean i screwed it out quite a bit and now i can here the fileter sucking really loud, it that my prob????

Help gas cost too much

 

240gl to a tank seems normal.. maybe alittle below normal.. have you changed your o2 sensor lately? makes a big diff in cruising gas mileage.

 

Im stupid where is the o2 sensor, and how do you check it, how many gallon gas tank

 

Go to this writeup, find the ECU pin for the S5's O2 sensor. Put the positive meter lead on the pin (helpful hints on how to do this are in the writeup), and the negative to ground. Drive the car...Watch the meter...

When warm, during cruise in 5th gear, you should see the meter needle (or digits if digital) bounce back and forth between .4 and .5 volts- that's the ECU in closed loop operation, and that is your best A/F ratio...Anything above .5v is running rich (you'll notice about .8v at idle, if yours is like mine), and anything below .4 is running lean...

Same scenario applies when you're romping on her...

Oops, forgot the writeup

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/troubleshooting-your-car-ecu-340578/