ECU with enabled VE map-fuel issues

[Matt]

Monitor the injection time at which you are making the changes and also get me a log and I can resimulate it here.

Also make sure you are adjusting the highlighted maps (if the knock maps is highlighted then main map wont have an effect)

[raddy]

Just remember that the VE map is used in cruise conditions. The accel increase map appears to be the TPS threshold at which the fuel map starts getting used

VE map trims additional fuel on top of the 14.7:1 stoich settings. VE map when adjusted will command these cruise conditions. You can always turn it off by disabling O2 flag and then just use the fuel map

Or otherwise adjust the accel increase map to use more of the fuel map instead if necessary

Just a quick note. I've always had my o2 flag disabled. If I understand correct the above, I've had the VE table turned off all the time. However, I was still not able to make changes in the fuel table which to result different AFR under certain conditions (mostly noticeable while in cruise).

from my experience it doesnt matter, if O2 flag is on or off in fuel map. With both options, it react to the VE map, but just very strange way... And also, it doesnt react to the main fuel map in both O2 flag conditions...

[Matt]

However I was not talking about O2 sensor in the fuel map. You should not turn it off in the fuel map on VE enabled ECUs (it is disabled in the software)

All values in the fuel map are 128-255 (raw value)

Feedback Control > O2 flag should be disabled instead. This will then stop the ECU from using the O2 feedback to trim in conjunction with the VE map settings as I observed during my investigations

[martin7937]

The only way to disable the o2 is by turning the flag off. Otherwise it is impossible to disable it on the fuel map (which fuel map is actually 100% flagged).
I will try what you say and will let you know.

[Ligouri Rd.]

I downloaded Matt's new Workshop Training Notes and need a bit more clarification. I have a '95 KA24DET ecu with a calum daughterboard for reference.

So The VE Map is accessed on top of the fuel table when the TPS is below the line in the Alpha/N Increase Fuel map, correct?
Once above the TPS level indicated, the Ecu refers only to the fuel map?
But setting the Alpha/N Increase Fuel map to 255 across the board will make the ecu access the fuel map only under all conditions? -This does not make sense since now we would always be below the Alpha/N Increase Fuel line.

Is the Alpha/N Increase Fuel map the same as or a revision of the Acceleration Inrease Fuel table (in the Nistune Mapping Guide)?

In the Workshop training notes it states "Turbo charged vehicles with no VE maps should disable this (Alpha/N TPS) flag or set(ting) the map to maximmum TPS voltage (raw value=255)" What should one do if they have a Turbo charged vehicle with VE maps?
-Use the VE map the tune out the AF Alpha trimming when in cruise (no boost)?
-Then use the primary fuel map to set the fuel in boost?

[Matt]

Alpha/N Increase Fuel map the same as or a revision of the Acceleration Inrease Fuel table

Yes it is the same

So The VE Map is accessed on top of the fuel table when the TPS is below the line in the Alpha/N Increase Fuel map, correct?

This is correct. I have noted that below this line the VE map coefficient is added to the fuel map coefficient

Once above the TPS level indicated, the Ecu refers only to the fuel map?

To be confirmed that it is not completely accessed

But setting the Alpha/N Increase Fuel map to 255 across the board

Is done for vehicles which are turbo charged and do not have VE maps

R34 Skyline for example has fuel + VE maps and this table is
126 126 126 126 158 190 190 190 190 190 190 190 190 190 190 190

Which is the point between VE+Fuel and Fuel being used.

This does not make sense since now we would always be below the Alpha/N Increase Fuel line.

Only for the earlier vehicles without VE maps, which access the last column only once above this line

[UNISA JECS]

Alpha/N Increase Fuel map the same as or a revision of the Acceleration Inrease Fuel table

Yes it is the same

So The VE Map is accessed on top of the fuel table when the TPS is below the line in the Alpha/N Increase Fuel map, correct?

This is correct. I have noted that below this line the VE map coefficient is added to the fuel map coefficient

Once above the TPS level indicated, the Ecu refers only to the fuel map?

To be confirmed that it is not completely accessed

But setting the Alpha/N Increase Fuel map to 255 across the board

Is done for vehicles which are turbo charged and do not have VE maps

R34 Skyline for example has fuel + VE maps and this table is
126 126 126 126 158 190 190 190 190 190 190 190 190 190 190 190

Which is the point between VE+Fuel and Fuel being used.

This does not make sense since now we would always be below the Alpha/N Increase Fuel line.

Only for the earlier vehicles without VE maps, which access the last column only once above this line

Seems as though a method for tuning the "AlphaN Increase Fuel" would be to log and view your tune and where the target AFR on the fuel map are not being followed adjust the "AlphaN Fuel Increase" to a point just below the threshold, this in turn should register as "RED" when the right criteria is meet and the VE Map will be ignored? Is that correct?

[Matt]

I havent used it that much. I would use the VE map (and alphaN if necessary) to adjust fueling outside the fuel map to make the AFRs line upto what the AFR display shows in the fuel map

[UNISA JECS]

1N4XX ECU/83JXX ECU

Now my issue-simply said, this ECU does not respond to values in fuel map at all.

whole table Accel increase fuel vs TPS voltage was set for 2000mV. I have strong feeling that this table actually contain condition of TPS voltage versus use of VE or Main fuel maps. By my opinion its not obvious acceleration enrichment....

As you have found Fuel map / VE usage is dependent on the Acceleration Increase fuel values. In older ECUs this table was used to use the TPS voltage to determine access the last column on the fuel map.

However with the VE map ECUs this table appears to determine if the fuel map values are used in addition to the VE map table. With my ER34 the AFRs at the lower end never needed adjusting so we did not noticed these same issues or needed to adjust the VE map. However I did note that adjusting VE did not have the expected effect. Now we know why since the table is TPS based

Accel enrich table
If you increase these (TPS) values for the specified RPM area then it will start using the fuel map in addition to the values in the VE map. This has been noted to work on the bench during investigations today

Note: The main thing during testing is monitoring the injection time (which consequently will be reflected by the change in your AFRs on the particular RPM/load point you are modifying)

Increasing the corresponding TPS value for the current RPM index on the accel increase table would make the ECU use the fuel map values as expected rather than trimming back on fuel map increase and just depending on the VE map values

Fuel map
It also was noted that adjusting the fuel map (increasing values) would actually reduce the injection time when O2 sensing feedback switch was enabled and the values in the Accel increase table were lower.

When disabling O2 feedback, the ECU is no longer looking at the O2 input and adjusting injection to maintain stoich trims. Same with increasing the values in the Accel increase table, the fuel map cell increases then took effect

VE map and trimming
Watch the injection trimming (AF alpha and AF alpha learn - short and long term trimming). Adjusting the VE map will result in additional trimming to occur in the map and injection to respond to making these adjustments. It may take upto 10-15 seconds for the ECU to monitor the O2 sensor and then adjust the injection to corresponding trimming (to reach 100%) as noted in the consult gauges (watch using the logger) in response to VE map changes

Trimming adjustments made by the ECU will affect all injection (global adjustment, similar to how K constant works). So watch for any trimming adjustments during tuning and then check the rest of the AFRs throughout the fuel map if the ECU has been trimming after VE map adjustments

Now if you are using the 0.12.11 version the VE map tracing has been fixed to follow the TPS position. I found that after bench testing that it will follow VE map changes. I noted today cells need to be changed one cell to the left of the cursor in this version. It appears maybe the trace needs to be moved left by onel. I will monitor next time I have the R34 plugged in

Let me know how you go given this information. All fuel map and timing scalers appear correct for these ECUs (so only inverted for K11 Type 5 ECU)

I see what you are talking about Matt

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

[Matt]

discussed in other thread. The TPS voltage < 500mV will go negative and throw off the tracing. May need to recalibrate this lower