why i cant run leaner on low rpms

[petersouza007]

Dear people;

I am trying to adjust my base maps to run leaner so i can save fuel. I was trying to input15.4 in the bASE maps but it won't allow me to. Maximum is 14.7 the ideal. If i have an external lamba sensor and it tells me i am running a bit rich so i can tune this map down. But it doesn't allow me to do that.
Does anyone know how to overcome this. Please help.


Thanks
Regards
Peter

[pmugabi]

Adjust your Front 02 sensor scaling, this should recalibrate your 02 sensor.

If that doesn't help much you can change your injector scaling (increase it), however this will most definitely require you to increase the AFRs on the fuel maps especially at high load as you will now be running leaner everywhere.

[chuckdez]

Dear people;

I am trying to adjust my base maps to run leaner so i can save fuel. I was trying to input15.4 in the bASE maps but it won't allow me to. Maximum is 14.7 the ideal. If i have an external lamba sensor and it tells me i am running a bit rich so i can tune this map down. But it doesn't allow me to do that.
Does anyone know how to overcome this. Please help.


Thanks
Regards
Peter

Use the RomRaider MAF calibration tool.

[petersouza007]

How do i adjust the front o2 scalings -1.3ma = 11.15 a/f & 0.0ma -= 14.7 af. So do i increase it at 1.3ma or reduce it if i want to run leaner. I am confused.

[chuckdez]

Most of our cars eat gas while in open loop NOT closed loop. I would calibrate your MAF spot on first. Shoot for +/- 5% of your target MAFv. I would look at leaning the O2 if you want to squeeze a tad more MPG out of your highway cruise control driving.

I'm 100% city driving in my STI, I went from 14-16 MPG in the city to 19-21 after MAF calibration. I could get better, probably 24 MPG, however I'm not a light footed driver.

[repforenzo]

I'm not sure if you have different map options that may allow you to change what stoitchmeter level is on your cars. For me, I had to tune the car exclusively in Open Loop to get 16.0:1 for idle and 15.6:1 for cruise. If my car stays in closed loop, then I'm stuck at 14.7:1 no matter what I change in the other maps. If the Long Term Fuel Terms (LTFTs) get too out of spec, the car will run like crap.

[Cap]

I Cheated by 'Adding' Voltage to the 'Ground Side' of my pair of o2 sensors.. So when it's in Closed Loop I can still 'Dial a Mixture' by the Offset Voltage that I'm putting on the low Side of the O2 sensor pair. I used a 10 turn pot off of a Divider circuit, and By the 'Dial' on the pot. I'm bumping it about .38 volt to get to 16-17 AFR.. Too me that seems a Little High ( the offset Voltage ) but it's working.. My ECU ( Toyota MR2 Spyder '01 ) DOES NOT LIKE THE OUTPUT FROM MY WIDEBAND LC-1.. So I had to fool it this way.. I can dial up the mixture past 19.. then I chicken out .. Light Cruse only.. Now I just need to figure out how to get the ECU to Quite 'Hunting' for mixture.. It has ROTTEN fueling habits.. Stock it will 'Hunt Up' to 14.7, then after 14.7 ( With the Overshoot in mixture ) it will turn around and 'Hunt Down' past 14.7, ( with Undershoot! ) then do it all over again.. Hunt up/down.. it never gets stable.. The AFR is about 1.5 'Wide' on it's Hunt.. I've played with the Voltage Divider on the O2 input lines.. and it 'Trips' at .45 volt.. no hysteresis .. so 'Smoothing' Nothin.. It just 'Snaps Over' at .45 volt .. Thinking of using a PWM circuit outputting to the O2 Sensor Input to the ECU, to help 'Ease the ECU in' to the 14.7 range.. It's a 'Binary' input ( Over or Under, nothing Else ), so a PWM will help .. I think.. Any body else tried this?..

[repforenzo]

Wow! I can say for sure that no one has tried your method. What an interesting solution. A basic variac on the o2 voltage. Nice job. I'll stick to using the ECUFlash to lean out the mixture.