Correct me if I’m wrong and I assure you it happens allot
Closed loop function basic explanation: The stock o2 sensor reports back to the ECU telling it that the fuel mixture just burned was either rich or lean, the computer then adds or subtracts fuel based on that report. Now for my question: Is there a table in the ECU that holds information on how many ms is added to the injector time and for how long if mixture was lean and vice versa if mixture is rich?
With the big injectors I’m running and also on other cars with injectors bigger then 440cc I’ve seen the AFR go crazy when closed loop is enabled.
Matt wrote:dare say that its not a table but a constant somewhere in the map area which it uses to add/subtract when it goes above/below voltage to correct
not sure where it is, I'm getting you're wanting the CA18 one?
Yes that would be great
Another question about idle AFRs: I have mapped cars with 550, 660 and 720cc injectors and all of them are running rich on idle. To get the idle at 14.7 the injector time needs to go under 2ms but on each car when we drop down to just under 2ms the afr goes hey wire and dances from really rich to really lean and so on. The only thing I can think of is either I’m missing something in the Nistune which controls idle injector time or the injectors them self can’t operate below 2ms. The later sounds wrong since there has been many of us running up to 720cc injectors with the original ECU just the boost cut removed and then a piggy back to modify LMM voltage to trick the computer in to giving different amounts of fuel.
and another note to above TTPmin table: John, did you disconnected standard lambda for setting idle afr? I would dont try to messing with idle if standard lambda is connected, that caused lot of problems at ca18det and any way of disabling it in nistune does not work, only really unplug it...but adjusting TTPmin can help a lot.
but cruising at closed loop should not cause any problem with bigger injectors, at all my tunes it holds 14.7:1 without any fluctuations during cruise, I used up to 660cc injectors.
raddy wrote:and another note to above TTPmin table: John, did you disconnected standard lambda for setting idle afr? I would dont try to messing with idle if standard lambda is connected, that caused lot of problems at ca18det and any way of disabling it in nistune does not work, only really unplug it...but adjusting TTPmin can help a lot.
but cruising at closed loop should not cause any problem with bigger injectors, at all my tunes it holds 14.7:1 without any fluctuations during cruise, I used up to 660cc injectors.
The stock O2 sensor is physically disconnected.
I've tried playing around with TTPmin and nothing happens whether its at the top or bottom, so for now TTPmin is 0 in all the cells.
Crusing is not a problem at all infact just starting the electric fan so a load comes on at idle makes it all work just because the engine then needs more then 2ms injection time to reach 14.7 AFR.
John wrote:
I've tried playing around with TTPmin and nothing happens whether its at the top or bottom, so for now TTPmin is 0 in all the cells.
this is not correct. My opinion is that you was changed TTPmax in reality, as in some versions of nistune are these tables reversed. Changing TTPmin at idle will definatelly affect idle AFR, for sure. Try to play with TTPmax instead at idle and watch AFR reaction. If you can get idle AFR reaction with TTPmax table adjusting, then in reality it is TTPmin table. In this case just set TTPmin (in reality TTPmax) to 255 all the way and try to play with TTPmax (TTPmin in reality) at idle.
In reality, if (real) TTPmin is set to 0, engine will die due to lean condition at idle.
John wrote:
I've tried playing around with TTPmin and nothing happens whether its at the top or bottom, so for now TTPmin is 0 in all the cells.
this is not correct. My opinion is that you was changed TTPmax in reality, as in some versions of nistune are these tables reversed. Changing TTPmin at idle will definatelly affect idle AFR, for sure. Try to play with TTPmax instead at idle and watch AFR reaction. If you can get idle AFR reaction with TTPmax table adjusting, then in reality it is TTPmin table. In this case just set TTPmin (in reality TTPmax) to 255 all the way and try to play with TTPmax (TTPmin in reality) at idle.
In reality, if (real) TTPmin is set to 0, engine will die due to lean condition at idle.
Looking at the AFRs and playing with TTPmin nothing happens.
Looking at the AFRs and playing with the TTPmax nothing happens until I reach the wery bottom and the engien cuts out.
But any way TTPmin and TTPmax are just thresholds for the injection time. If both are set to there max/min values TTPmax to 255 and TTPmin to 0 or vice versa if like you say in some Nistunes the tables are reversed, you are affectivly disabeling this function and they should not mather when it comes to injection time, Is this assumption correct?
John if you are not using innovate currently (cos the Logworks DLLs in NIStune Version 0.9.13.1b dont work) then use that particular version
Its got the updated CA18 address file. TTPmin min works and now displayed correctly. I got minimum pulsewidth to 0.5ms (k = 0, latency = 0 map cells = 0, TTPmin = 0) and adjusted TTPmin and it kept increasing pulsewidth
TTPmax on a certain high pulsewidth will reduce that width as you keep reducing the table also
