14 ram stoich fa not responding

[[email protected]]

I have a 14 ram that im trying to get the stoich fa to be lower than 14.7. right now its .0688 and id like to get it to .0700 but in the scanner the commanded afr is still reading 14.7. do i leave pe alone and mess with the inj and fuel mass tables to try and achieve the afr i set in the stoich table?

[HaasExp]

It has factory N/B O2 sensors thus regardless of what you put in the stoich FA it will always target lambda 1 which is 14.7 for gasoline when in closed loop. Changing the stoich FA will just skew the fuel trims in CL but it will affect the actual AFR under open loop conditions.

[Higgs Boson]

It has factory N/B O2 sensors thus regardless of what you put in the stoich FA it will always target lambda 1 which is 14.7 for gasoline when in closed loop. Changing the stoich FA will just skew the fuel trims in CL but it will affect the actual AFR under open loop conditions.

stoich for ethanol free gasoline is 14.7

stoich for E10 is 14.08

depends what's at your pump. if you are running E10, which 99% of the US is, changing stoich to 14.08 will reduce trims.

[[email protected]]

so pretty much im stuck with the 14.7 stoich ratio, while in closed loop. what if i was to lower the throttle votlage so that i can use the wot fueling table to get the afr i want ? i ask this because im getting some spark knock while accel but not wo accel.

[B00STJUNKY]

so pretty much im stuck with the 14.7 stoich ratio, while in closed loop. what if i was to lower the throttle votlage so that i can use the wot fueling table to get the afr i want ? i ask this because im getting some spark knock while accel but not wo accel.

Disable o2 sensor feedback. You can command whatever Lambda value you want when in open loop, and won't have any o2 sensor feedback stepping in to bring you back to Lambda 1.0.

[skala308]

If I may chime in here. The FA in our tunes (factory) of 0.0688 = 14.53AFR.
It is true, that using a wideband stuck in the tailpipe of my Jeep at CL gave 14.7AFR.
I have also changed the stoich tune values and the fuel trim (FT) log histogram becomes more red (lean) with a lower FR value and more green (rich) with a higher FA value.

so, how do we get our motors to run more economical? Can it be done by leaving the FA value at factory of 0.0688 and adjust the VE tables so that the logged FT is within +- 5% in CL conditions?

Thanks for the info so far.

[HaasExp]

so, how do we get our motors to run more economical?

To attempt this with what you have would require you to run OL all the time, setting the stoich to something leaner and tuning the VE to match the target AFR (set by your stoich) by using a WB o2 sensor.
However, you will then have no closed loop fueling feedback and therefore, all your temp/baro corrections/multipliers must be spot on to try and maintain your target AFR with reasonable accuracy.
This could help with economy

[skala308]

Thanks HaasExp, I get it and it is as I understood with all the meaningful inputs form yourself and other guys (Hemituna, Ben Charles, Janettyracing) on my previous queries.

So, know what is your fuel blend, set the tune stoich for that and the NB sensors will target lambda 1.0 and ECU will either add or subtract fuel to maintain lambda.
Then from the logged data, the main VE table values can be adjusted to give +-5% logged data. This will reduce the over/under fuelling at different cells and should improve fuel efficiency for the fuel you are using.
This is disregarding the other adders such as ETC, IAT, Baro and driver demand, and also staying in CL. This will also take care of PE or WOT, without changing any of the PE settings.

I have reduced the WOT voltage to 2.8 (also in torque driver demand), plus set the delay to 0.000ms. My Jeep drives well.

In South Africa we have about 5% ethanol in our fuel, so for my Jeep, as most Chrysler 5.7hemis, the factory stoich of 0.0688FAR is good. That = 14.53AFR.