Thread: ECU with enabled VE map-fuel issues - in Nistune

Can someone help/explain how works VE table in Nistune? I have problem with fuel tuning:

As was already mentioned here: viewtopic.php?f=11&t=1115&start=15

there are some ECUs-in my case Almera N15 SR20DE, ecu 1N4XX- that have enabled VE map. Another point is that this ECU have enabled O2 flag in entire fuel map. Now my issue-simply said, this ECU does not respond to values in fuel map at all... Im able to affect AFR by K konstant and by altering VE map. But even in VE map, I dont understand exactly how it affect AFR, as reaction is like random and I didnt found any system here... With connected OEM labmda, I dont have an issues with idle or with crusing, but full throttle AFR is somehow generated...Change of VE map will affect AFR, but it is really not possible to set whole load range to desired AFR. VE map have different RPM/load scales, spacially RPM scale is limited to 6375rpm, however rpm limiter in my case is at 8500rpm... I would really appreciate any help or input here...Thanks a lot

just to add that N15 Pulsar/Almera SR20DE ECU 0A5XX, 1N96X, 1N97X doesnt have VE table nor O2 flag in entire map...

Thanks

Matej

VE maps are not properly enough defined/known to really mess with them. If you have the O2 flag enabled for most of your map, your input will be ignored in those cells.

Now remember that the fuel map is not a real target AFR map, because our cars never shipped with a WBO2 sensor. Thus in your WOT cell's expect to see crazy high or low numbers and in real life you will have something completely different.

OK, but than there is no way how to adjust AFR properly in my ECU with Nistune... Or how to solve it?

Based on my experience in working with Nistune on my own car here's what I can try to help answer for you.

1-Because of what Vadim pointed out, when working with the fuel map I always use the Raw Values view. The Estimated AFRs view is always way off and not even relevant anyway.
2-A value of 128 in any cell when looking at the raw value will indicate it's attempting to follow the O2 sensor. Raising the value will make sure that cell is not following the sensor reading.

Many thanks,

but We have already sorted our problem out... Raddy did it for me:
Nistune Forums • View topic - ECU with enabled VE map-fuel issues

Nice link good info, VE maps have always been confusing, now it's clear as muddy water lol.

The VE fuel map would be very simple to tune is the damn tracer actually followed the correct cell block being accessed, its very frustrating and I have zero faith in it what so ever, however if this trace ever gets figured out you can very easily make your fuel map values actually match your wideband.

There is a lot missing to the VE fuel table and it sucks for now hopefully it'll be figured out.