Speed density MAP Multiplication - idle floating problem

[TomSK]

Hi guys,
i need little help. Can anybody tell me what is "Speed density MAP Multiplication" in calculations in newer firmwares?

I cant modify this factor in VT and cant find any valuable informations about it.
This multiplication makes my idle unstable and floating at lambda 1.0, because it changes Injectors PW. All others corrections and VE values are stable. At idle (cca 800rpm) MAP readings very small floats, just 1-3kPa but this function multiplicate this MAP values and then calculation model change PW which means that lambda is floating, idle air valve is floating, etc....
When i make lambda table richer, and turn on WBO2 closed loop control, idle is stable, but engine runs lambda 0.85-0.9 on idle. 

Can anybody please tell me how to fix this problem or  where to disactivate this multiplication in VT?

Thank you very much 



http://www.vems.hu/files/LanciaSlovakia/speed-density.jpg

[Kamuto]

it's a one of the most important features to get engine working, you cant disable it and you must have it working, it's map multiplication, base fuel 6ms map 100kpa=6ms, map 50 kpa=3ms, map 200kpa=12ms with same fuel table value, so I  believe it's your injecor settings or something other causing the problem

[fphil]

Indeed but this map multiplication may not be fully linear in reality . At low rpm this multiplicative factor seems equally a bit high for me and may induce rpm instability unless one carefully tunes the VE map.. Hence the need sometimes to have a dedicated low rpm VE map

[Kamuto]

Indeed but this map multiplication may not be fully linear in reality . At low rpm this multiplicative factor seems equally a bit high for me and may induce rpm instability unless one carefully tunes the VE map.. Hence the need sometimes to have a dedicated low rpm VE map

usually that's not the map multiplication problem but injectors are not linear in low pw