Tuning VE Fuel Map

[UNISA JECS]

So Matt what do you think about me adjusting the VE values where they do not follow the target AFR's? I suppose this should increase fuel correct?

Attached bin and log only consist of a couple 1st 2nd and partial 3rd gear pulls

These are just some time lapsed screen shots of the problem areas (more of the same can be seen if you view the log and bin file.

[UNISA JECS]

After making changes basically all the (105.5) looks like AFR are going in the right direction just look at the VE FUEL TABLE Column 96 in particular and you'll see were I made changes the AFR are now about 2 AFR richer in the right direction

p.s. I will be making more changes and posting them up but im happy to see these changes actually working.

p.s.s. You might catch that I actually extended my VE Table to 255 as standard it goes to 128 but I think this way gives much more resolution instead of flying right over to furthest colum to the right.

[UNISA JECS]

Ok I think I figured out my problem as to not being able to make my fuel table AFR match my wideband AFR and the answer was to enable
"Alpha/N TPS" and most importantly adjust the mV down low enough so that the main fuel map would be followed instead of whatever else its doing with the VE map wish I knew.

[Matt]

That table indicates that TPS position is required to determine when to use the VE map (which itself is TPS based). It seems to affect fueling based on TPS position rather than TP like used in the fuel maps

Adjustment to the VE table will affect fuel injection accordingly which can be used to trim AFRs instead of the fuel map

[UNISA JECS]

Hey Matt its seemed I stumbled across something that you may want to correct, it appears the VE FUEL MAP tracer is off, perhaps its mirrored, I included a video to prove this, I have literally been tuning/messing around with this VE FUEL TABLE all day and I believe this is why I been having scattered success, it would be really nice to have this tracer corrected, thanks.

Incorrect VE fuel map tracer video below:

I recommend you watch FULL SCREEN 720p so you can see that I am making changes on the fly to the fuel table and watch the results via my wideband, changes are instant.
http://youtu.be/BfINxg2yIIs

[UNISA JECS]

Hey Matt is it possible that maybe this VE map trace is tied to the TPS Sensor and that it needs to be calibrated to the TPS sensor in some way that it is looked up automatically?

I look at the VE Fuel Map as 4 parts so I did the following I figured at closed throttle my TPS voltage is .48v and WOT is 4.1v so I then took .48v multiplied it by 204.6 got 98 then divided it by 4 and got 24 then I did the same for my WOT voltage which is (4.1v * 204.6) / 4 = 209

I got 204.6 from 1023 bit = (5v)

(TPS(v) * 204.9) / 4 = X

Heres a video of the map trace (modified) I know it does not follow 100% accurate but perhaps its leaning towards the right direction its really frustrating cause not having the tracer exactly where it should be is useless for tuning the VE map to correct the AFR, but if it was spot on accurate it would be child's play! Hopefully this can be figured out.

http://youtu.be/o10ZTsVJB4k

[unreal-]

This is quite interesting topic. I had tried using the "set ve to 255" method and my car was freaking out some reason it wouldnt respond properly to the ve table. It would be awesome to have the ve table actually trim the whole fuel map instead of going immediately to the right once you get into boost.

Since im running open loop at the moment the ecu seems to be following the fuel map pretty closely for some reason, but my afrs are decent...but could be better.

[UNISA JECS]

This is quite interesting topic. I had tried using the "set ve to 255" method and my car was freaking out some reason it wouldnt respond properly to the ve table. It would be awesome to have the ve table actually trim the whole fuel map instead of going immediately to the right once you get into boost.

Since im running open loop at the moment the ecu seems to be following the fuel map pretty closely for some reason, but my afrs are decent...but could be better.

No matter what you do weather it be unchecking the Alpha/N TPS (Add Fuel) Flag or move the Alpha/N Increase Fuel vs TPS voltage below idle TPS voltage or above WOT voltage the Fuel Volumetric Efficiency table remains active and will have an influence.

The Fuel Volumetric Efficiency table cursor follows the TPS voltage voltage, it just so happens for what ever reason the way that it is set up stock (Max 128) that's 1.86v and if you increase it to (Max 255) that's 3.72v

Following that trend:
0 0v
128 1.86v
255 3.72v
383 5.00v

or

0 1v
128 2v
256 3v
384 4v
512 5v

I just have this feeling there's some relationship here

Hey Matt would it be possible to see how this works out by increasing this scale to 383~ and enabling the RPM scale to be adjusted further?

See video below:

http://youtu.be/1lb6kaK0STs

[UNISA JECS]

Another thing I noted is that if I change my VE RPM Scale to match my Fuel RPM scale which by the way the VE RPM Scale is limited to 6375rpm this does at least put the VE Fuel Map cursor on the correct horizontal plan which is helpful but the vertical plan is still off by varying amounts of columns.

[Matt]

I'll have to hook hardware maptracing upto the B14 ECU and try it out again. I did notice that the AlphaN table affects how the VE table is used but does not stop it being used completely when TPS exceeds the table values

Currently I have (TPS - 500) * 64 / 1000 as the forumla where TPS is in millivolts. That is what I used on my R34 to calibrate the cursor on the maptrace. This was matching the hardware trace against the calculated software trace

For your vehicle the 480mV this ends up negative which is why your video shows an incorrect location. The video did not show any adjustment to TPS (going above 500mV) only that you were changing the AFRs in cells to the left (and lower).

Try and keep the discussion for this in one thread as there are three separate threads going at the moment and become difficult to follow up from this end.

Wont be able to look at this for about a week since got other workload at the moment

[UNISA JECS]

I'll have to hook hardware maptracing upto the B14 ECU and try it out again. I did notice that the AlphaN table affects how the VE table is used but does not stop it being used completely when TPS exceeds the table values

Currently I have (TPS - 500) * 64 / 1000 as the forumla where TPS is in millivolts. That is what I used on my R34 to calibrate the cursor on the maptrace. This was matching the hardware trace against the calculated software trace

For your vehicle the 480mV this ends up negative which is why your video shows an incorrect location. The video did not show any adjustment to TPS (going above 500mV) only that you were changing the AFRs in cells to the left (and lower).

Try and keep the discussion for this in one thread as there are three separate threads going at the moment and become difficult to follow up from this end.

Wont be able to look at this for about a week since got other workload at the moment

Hey Matt have you had anytime to look into this?

[Matt]

Not yet. I've got several other things going. Trying to remove OBD-II codes from the later ECUs at the moment. This is proving very difficult

[UNISA JECS]

Not yet. I've got several other things going. Trying to remove OBD-II codes from the later ECUs at the moment. This is proving very difficult

Ok........so from what it appears from what you said that the trace is kinda dependent on what your base idle TPS voltage is, if that is the case wouldn't it be better to have some way of Nistune determining what your base idle TPS voltage is since everybodys idle TPS voltage will vary from vehicle to vehicle and the range as per the FSM for the B14 SR20DE is .45-.55v


P.S. since you stated that you worked on the trace for the VE MAP on a R34 what voltage did you set your idle at perhaps I can for now just re-adjust my idle TPS voltage in the mean time.

Thanks
Charlie