VEMS overrun fuel cut

[A80Avant]

yes, that was another suggestion from the developers, that the fuel resume is as high as 800rpm from your idle, but in my car that caused hiccups esp. when cold and driving at very low revs in the city. This is why i finalised using 1300-1400rpm on resume/cut respectively.

if your car is cutting at different rpm than what specified there may be a problem with the accuracy of the rpm signal. What flywheel do you use?

[KRIENG]

stock flywheel form Urs4 Y92 manual trans

Thank you again
stock flywheel form Urs4 Y92 manual trans

In first I don't know why my engine stall,but now I understand it.
and I will try some of yours information and LOG to see how difference
and report.

[A80Avant]

hmm it should be ok. seems odd to cut out on a different rev than what log shows.

i am starting to doubt vems ability to log rpm properly as i have a modified 7A flywheel and the pin has been modified for vems to 'see'

anyway, try various combinations, you are bound to get it right.

[KRIENG]

IAC lower DC

when A/C on and decelate RPM drop&stall
I found about IAC lower DC limit,and will test

http://www.vems.hu/wiki/index.php?page=MembersPage%2FVasilisP

[A80Avant]

yes that link is my page.

my lower limit is still 29 and works fine.
However, when putting it to 29 you may find that it does nothing to the stalling issue as around that figure is when the ISV valve stays shut, while if it goes beyond that it re-opens.

[Erikk]

I almost always use the Pressure controlled overrun fuelcut, as its easy to configure.

Just rev to 4000rpm´s (while in some gear) and let off the throttle totally, you will see that pressure in the manifold goes really low, eg. 25kpa.
While rpm gets lower, the pressure starts to add up, maybe up to 32kpa @ 1600rpms, just set the Overrun fuelcut to 30kpa and it will automaticly resume the fuel @ around 1800-2000rpms.

[dkw_dude]

For smoother transition at low load <--> idle, enable "IAC follows TPS when not idle" (I'm still on 1.1.70, it's in the idle settings dialog box on this firmware) Made a notable difference on my car!
Earlier I disabled the D part of the idle PID regulator, enabled it a while ago and tuned it, it also helps a lot i keeping the idle steady. Very Motronic'ish smoothness at town driving now!

[KRIENG]

I set to this Pic and config ISV DC too

Problem are solved, Many thank you all.