When I let off the throttle my afr goes really lean 22:1 (pegs WB) How can I stop this or at least not make it so drastic of an afr change.
I believe that this leads to the stall that I get when pressing in the clutch.
I have found that if I am going rather slow so that there is not a long period of 22:1 before the clutch is pressed in it doesn't stall.
However, if I am say doing 45 or more and it is at this afr for a while because I am off the gas and then I press in clutch it stalls.
I did a bit of messing with the decel fuel cut-off moving the upper and lower limits, still get the 22:1. Also moved the speed below which decel is disabled mph limit from 35 to 80. No effect.
would be the best locations to concentrate on to solve this?
Here is some of the data on throttle%, RPM, MAP and AFR
You can see where it stalls when the clutch is pressed in
--Tom
I believe that this leads to the stall that I get when pressing in the clutch.
I have found that if I am going rather slow so that there is not a long period of 22:1 before the clutch is pressed in it doesn't stall.
However, if I am say doing 45 or more and it is at this afr for a while because I am off the gas and then I press in clutch it stalls.
I did a bit of messing with the decel fuel cut-off moving the upper and lower limits, still get the 22:1. Also moved the speed below which decel is disabled mph limit from 35 to 80. No effect.
would be the best locations to concentrate on to solve this?
Here is some of the data on throttle%, RPM, MAP and AFR
You can see where it stalls when the clutch is pressed in
Code:
ThanksTPS % RPM MAP (2-bar) Target AFR % RPM KPA 16 2825 43.15 14.9 0 2750 24.4 14.6 0 2825 17.37 14.5 0 2725 15.81 17.8 0 2775 15.81 20.5 0 2725 15.03 21.3 0 2775 15.81 22 0 2725 15.03 22 0 2725 15.81 22 0 2700 15.03 22 0 2700 15.81 22 0 2650 15.81 22 0 2700 15.81 22 0 2625 15.81 22 0 2625 15.81 22 0 2650 15.81 22 0 2625 15.81 22 0 2625 15.81 22 0 2550 15.81 22 0 2575 15.81 22 0 2575 15.81 22 0 2525 15.81 22 0 2525 16.59 22 0 2525 16.59 22 0 2500 16.59 22 0 2425 16.59 22 0 2475 16.59 22 0 2475 16.59 22 0 2400 16.59 22 0 2400 16.59 22 0 2400 17.37 22 0 2450 16.59 22 0 2400 16.59 22 0 2350 17.37 22 0 2325 17.37 22 0 2350 17.37 22 0 2375 17.37 22 0 2350 17.37 22 0 2325 17.37 22 0 2325 17.37 22 0 2275 17.37 22 0 2275 17.37 22 0 2250 17.37 22 0 2275 18.15 22 0 2250 18.15 22 0 2250 18.15 22 0 2250 18.15 22 0 2250 18.15 22 0 2225 18.15 22 0 2225 18.15 22 0 2225 18.15 22 0 2200 18.15 22 0 2200 18.15 22 0 2150 18.93 22 0 2175 18.93 22 0 2150 18.93 22 0 2150 18.93 22 0 2125 18.93 22 0 2100 18.93 22 0 2075 18.93 22 0 2075 18.93 22 0 2025 18.93 22 0 2050 18.93 22 0 2050 18.93 22 0 2050 18.93 22 0 2025 18.93 22 0 2000 18.93 22 0 1975 18.93 22 0 1975 18.93 22 0 1975 19.72 22 0 1975 19.72 22 0 1950 19.72 22 0 1900 19.72 22 0 1925 19.72 22 0 1900 19.72 22 0 1900 20.5 22 0 1875 20.5 22 0 1875 20.5 22 0 1875 20.5 22 0 1825 20.5 22 0 1800 21.28 22 0 1800 21.28 22 0 1775 21.28 22 0 1800 21.28 22 0 1775 21.28 22 0 1750 22.06 22 0 1750 22.06 22 0 1725 22.06 22 0 1700 22.06 22 0 1675 22.06 22 0 1650 22.06 22 0 1625 22.06 22 0 1625 22.84 22 0 1575 22.84 22 0 1575 22.84 22 0 1550 22.84 22 0 1575 22.84 22 0 1500 22.84 22 0 1525 22.84 22 0 1475 22.84 22 0 1450 23.62 22 0 1450 23.62 22 0 1450 23.62 22 0 1425 23.62 22 0 1400 23.62 22 0 1375 23.62 22 0 1350 24.4 22 0 1350 24.4 22 0 1325 24.4 22 0 1300 25.18 22 0 1275 25.18 22 0 1250 25.96 22 0 1200 26.74 22 0 1200 26.74 22 0 1125 28.31 22 0 975 29.87 22 0 800 32.99 22 0 650 37.68 22 0 450 43.15 22 0 325 52.52 22 0 200 59.55 22 0 200 59.55 22 0 200 59.55 22 0 0 59.55 22 0 0 59.55 22 0 0 59.55 22 0 0 59.55 22 0 0 59.55 22 0 0 59.55 22 0 0 59.55 22 0 0 59.55 22 0 0 59.55 22 0 0 59.55 22 0 0 59.55 22 0 0 59.55 22
--Tom
Senior Member
AFR - Open Loop AFR - closed throttle
AFR - Open Loop AFR
Look at those 2 tables. Sounds like you or somebody else changed them from stock.
AFR - Open Loop AFR
Look at those 2 tables. Sounds like you or somebody else changed them from stock.
RednGold86Z
Supreme Member
close
May 8, 2026
It's going lean from decel fuel cutoff - DFCO (not decel enlean - DE). Almost all EFI systems do that unless it's disabled. I don't recommend disabling it, but it's your car. It has some RPM and MAP thresholds that you can raise to exit the cut earlier - start there. Exit it at 1400 and 24 kPa and see what happens. Also, make sure you have some timing there (greater than 20 degrees - is there a closed throttle table for timing in $58?? else use main table) Make sure you have some VE there too. The stall is likely from too small VE in everything below AND above idle MAP AND RPM below IDLE.
Quote:
Originally posted by RednGold86Z
It's going lean from decel fuel cutoff - DFCO (not decel enlean - DE). Almost all EFI systems do that unless it's disabled. I don't recommend disabling it, but it's your car. It has some RPM and MAP thresholds that you can raise to exit the cut earlier - start there. Exit it at 1400 and 24 kPa and see what happens. Also, make sure you have some timing there (greater than 20 degrees - is there a closed throttle table for timing in $58?? else use main table) Make sure you have some VE there too. The stall is likely from too small VE in everything below AND above idle MAP AND RPM below IDLE.
I will have the DFCO a try, I had already moved the Upper limit from 1600 to 2800 and the lower limit from 1100 to 1600. However, I did not change the map which was set at 43kPa. Originally posted by RednGold86Z
It's going lean from decel fuel cutoff - DFCO (not decel enlean - DE). Almost all EFI systems do that unless it's disabled. I don't recommend disabling it, but it's your car. It has some RPM and MAP thresholds that you can raise to exit the cut earlier - start there. Exit it at 1400 and 24 kPa and see what happens. Also, make sure you have some timing there (greater than 20 degrees - is there a closed throttle table for timing in $58?? else use main table) Make sure you have some VE there too. The stall is likely from too small VE in everything below AND above idle MAP AND RPM below IDLE.
So my values are already higher than what you recommended if I read what you are saying.
$58 does not have a closed throttle spark table just ve, so I checked values in main table and they are 20 ish.
I guess I will have to concentrate on the closed throttle ve tables.
I was reading more up an defco
Does anyone know where the location for KDFCDTMR is located?
I was not able to find it in the hacks
This is suppose to be the timer for dfco.
Does anyone know where the location for KDFCDTMR is located?
I was not able to find it in the hacks
This is suppose to be the timer for dfco.
Supreme Member
Quote:
Originally posted by novass
Does anyone know where the location for KDFCDTMR is located?
I was not able to find it in the hacks
Nothing I have shows it.Originally posted by novass
Does anyone know where the location for KDFCDTMR is located?
I was not able to find it in the hacks
LC370: FCB 80 KDFCOSPH Decel Fuel Cut-Off Upper RPM Limit, NTRPMX Units 2000 RPM
LC371: FCB 56 KDFCOSPL Decel Fuel Cut-Off Lower RPM Limit, NTRPMX Units 1400 RPM
LC373: FCB 128 KDFCOG Decel Fuel Cut-Off Multiplier Step Value 50.00 %
You might try setting the KDFOSPH, and L to some values higher then you normally use, and then use the closed throttle table instead of DFCO. I thought there was a temp enable for the DFCO, but I couldn't find it.
Might try playing with the KDFCOG.
Not having had a stick just guessing here on what to try.
Could it be something else becides dfco?
I basically disabled DFCO my setting at 372 KDFCOMAP to 10
and 37B KDfcoslk to 90.
Still when I lifted off the throttle my AFRs went to 22?
This should rule out DFCO, or some how I am not disabling it.
I also increased my low map buy 35%values in both closed throttle tables and regular ve tables and still AFR went to 22?
From my understanding when the rpm's are above 1600 it uses the VE from the standard table.
Any other thoughts?
edit I also set DFCO multiplier to 10% and had same results.
I basically disabled DFCO my setting at 372 KDFCOMAP to 10
and 37B KDfcoslk to 90.
Still when I lifted off the throttle my AFRs went to 22?
This should rule out DFCO, or some how I am not disabling it.
I also increased my low map buy 35%values in both closed throttle tables and regular ve tables and still AFR went to 22?
From my understanding when the rpm's are above 1600 it uses the VE from the standard table.
Any other thoughts?
edit I also set DFCO multiplier to 10% and had same results.
Supreme Member
Quote:
Originally posted by novass
Could it be something else becides dfco?
Ya, could be, said DFCO. Originally posted by novass
Could it be something else becides dfco?
Could be closed throttle timing, or too *much*/ *slow* IAC.
BTW, isn't there a manual tranny flag?, and do you have it correctly selected?.
Quote:
Originally posted by Grumpy
Ya, could be, said DFCO.
Could be closed throttle timing, or too *much*/ *slow* IAC.
BTW, isn't there a manual tranny flag?, and do you have it correctly selected?.
Manual trany flag set.Originally posted by Grumpy
Ya, could be, said DFCO.
Could be closed throttle timing, or too *much*/ *slow* IAC.
BTW, isn't there a manual tranny flag?, and do you have it correctly selected?.
Raised up closed throttle timing, was a bit lower than what was in $8d. A bit better for the slower (less time that the afr's are at 22) However, when I have a long rev down and then push in clutch, still stalls.
I tried rasing the IAC power steering stall rpm from 500 to 650, no help. I even raised the inital Iac pulses from 8 to 40, did not see improvement.
How would I speed up IAC?
If I am in a long rpm rev down and press in the clutch and then release it before the stall occurrs and then press in the clutch again, it does not stall.
Also, I did not state above all tuning at this point is in open loop.
Any other suggestions would be appreciated.