Modifying the BIN
Injector K Value - K Value, in short, is a multiplication factor for injector pulsewidths. Now Dave from TunerCode was able to see that the K value does a lot of things within the ECU. This is why with TunerCode you don't modify the K value for new injectors. Since a lot of things depend on this multiplication factor, it's best to keep it as close to the stock value as possible (B13 K Value=31206, B14 K Value=298).
If you don't have TunerCode, then you are required to modify the K Value, because there is no other way get the new Injectors or MAF to work. Just remember to rescale your TP Scales. If you don't you might be running too much timing or not enough fuel while you are in boost.
How is K value calculated?
TP = (VQ x K Value / CAS Value) / Number of Cylinders
Formula for new K Value:
(Old INJ Size / New INJ Size) * Old K Value = New K Value
In this example we take a stock B14 tune and add 370cc injectors to it.
(259cc / 370cc) * 298 Old K Value = 208 New K Value
Injector Latency - This controls how long the injector stays open. Bigger injectors don't need to stay open as long, because they spray a lot more fuel, thus this value needs to be adjusted down. You will see the biggest difference when you adjust the values at idle.
Injector Scaling Constant (B14 Only) - CC value for the injectors. Probably is used for a calculation. I haven't noticed the Scaling Constant on B13 BIN's. You can find a good number of
Nissan VQ Tables here.
MAF Voltage Point - Low: If your MAF voltage falls below this voltage for a certain amount of time, the ECU will enter into Limp mode. If your MAF is old and tired and you can't replace it yet, you can lower the the low MAF voltage point. If your MAF idles below 1.0v, then it's defective and needs to be replaced,
more on this.
Operational MAF Voltages as per FSM.
VQ Table: The MAF reads voltages based on airflow, this table helps the ECU match the voltages from the MAF to the values that the ECU can understand. If you have a proper VQ table and voltage match-up, you can use any 0-5.12v MAF on this planet.
When you change MAF's, you need to update the VQ table with the new MAF's values, you will also need to update the K Value, which means you have to update the TP Scales too. Unless you have TunerCode, then you can get your AFR's up or down using the Current Injector Size scalar.
TTP Min(B13 Only): Minimum Total Theoretical Pulsewidth for injectors at a given RPM. Since bigger injectors don't to stay as long as the smaller injectors, adjusting the TTP Min helps avoid extra fuel richness.
TTP MAX: Maximum Total Theoretical Pulsewidth for injectors at a given RPM. As you get more power, TTP Max might restrict you from flowing any more fuel. Adjust accordingly.
Warning don't even bother adjusting the Fuel/Timing Maps without a wideband.
Fuel Maps
There are four fuel maps total; Primary No Feedback, Primary Feedback, Secondary No Feedback, Secondary Feedback. It's still not exactly clear what the secondary maps are for, some say they might be low octane maps. What I've always done is copy the primary no feedback map and paste it onto the secondary no feedback map.
No Feedback Map
To get started, open the No Feedback map, everything that is not in 100's can be modified in this table. You will use the No Feedback map to tune the partial throttle to full throttle. If you try to modify any ~192 valued cells, TunerPro will change them to be 100, thus you have to use the Feedback map to modify those items. This is actually a TunerPro feature, maximum value per cell, you can increase it, but then your cell coloring will become blander.
Feedback Map
In the feedback map, you can tune your cruising/light driving cells. You will notice that the cells that used to show 100+ values now show regular 0's and 10's.
How Feedback works for fuel maps: When you are in the No Feedback map, you will see a bunch of rather high numbers, around 192. That means that is the part of the cell where the O2 sensor feedback will be used. Tuning the O2 feedback areas is not as important as tuning the higher load/RPM areas, because O2 sensor readings will be used to keep the car near 14.7 AFR's. You still want to tune the Feedback portion of the map though, they will be used as the AFR base for the ECU to compare against the actual O2 sensor readings, plus if your O2 sensor gets disabled, ECU will use the values in the cell's for the fuel amount.
You can also easily convert feedback areas to not have feedback at all.
192 = 0, just subtract 192 from all of the feedback cells. You will get the actual number that the ECU would use.
For ECU's that use Target AFR's (Mainly OBD2). Feedback enabled portions are 14.7's. Anything above 14.7 is still used O2 sensor feedback by the ECU, anything below that uses the map instead of O2 sensor.
It is a lot harder to lean out ECU's that use Target AFR's. You basically have to keep the values below 14.7 and turn the K value way down. This is not a good idea either, because OBD2 ECU's rely heavily on the O2 sensor and tend to lean out under boost for a few seconds.
Note: Before tuning the fuel maps, disable your O2 sensor, and adjust your K value (if using TunerCode Current Injector Size) so that your cruising AFR's are as close to 14.7 as possible. Then start adjusting the Fuel Maps to get the proper air to fuel ratios while under load.
This is a OBD1 map, OBD2 maps have target AFR's which are more self explanatory.
Timing Maps
There are four timing maps; Primary and Secondary, Normal and knock map. Timing maps control the spark advance, the higher the value in the cell, the earlier the spark will fire Before Top Dead Center (BTDC). Fire the spark too early and you will get detonation.
The feedback and no feedback maps work exactly like the fuel maps do, except feedback starts cells with 128*.
How Feedback works for timing maps:
All of the values above 128 have the Knock Sensor feedback enabled.
You can also easily remove the knock sensor feedback areas,
128 = 0*, so subtract 128 from all of the feedback cells.
RPM Scales: You can define which RPM points you want to show up on the Fuel and Timing Maps so that you can adjust the fuel and timing. The ECU will interpolate between two RPM points and extrapolate above the maximum RPM point.
There are two RPM scales; one for the Fuel Maps and the other one for the Timing Maps. It's generally a good idea to keep these consistent for easier tuning. The ECU will always round up to get the next top cell.
TP Scales: Similar to the RPM scales, accept this is for engine load. ECU will interpolate in between the TP Columns, and extrapolate if your TP is higher then the maximum TP. Adjusting the TP scale is very vital to make sure you have the right amount of fuel in the higher loads, especially when in boost.
With TP scales, you do want to keep the TP values fairly close together so that the ECU doesn't have to interpolate too much. I've noticed a lot of engine knock simply because my TP scales where too far apart and while the ECU was interpolating it didn't pull the timing back fast enough under boost.
To find the maximum TP, do one run while datalogging your TP and see what was the highest TP that you hit. Set the last column to be a little above that (ie: if you hit max 105TP, then set the last column to be 110 or so), that gives you a little head room.
If you set your TP values too high, ECU will never reach them, depending on how your tune is, you might be in the column for 5 psi while you are boosting 10 psi. This could be fetal to your engine. If you set your TP values too low, then you run the risk of dumping too much fuel while not having the sufficient airflow because your engine load is too low. I personally ran into this issue, when I was first beginning to tune, pressing the throttle slightly would give me 10-11:1 AFR's. This made my performance and gas mileage suffer. By properly adjusting the TP Scale, you should be able to get your AFR's be just right.
0200 - TPS Enrichment Trigger:Unfortunately this one is only available to the OBD1 ECU's. Simply put, when the voltage is above the listed TPS Voltage, based on RPM, the ECU will go to the right most column of a fuel map and use the fuel amounts from that column. This is done to give a little more richness to help compensate for fast throttle opening, even though there is a Fast TPS enrichment table too.
This Enrichment trigger is only used on NA cars by Nissan. Turbo SR20 ECU's have this this disabled and all of the voltages set to 5.10v. Otherwise you will use fuel amounts for say 10psig when your still in vacuum. Which means very rich AFR's and you are just dumping fuel and loosing power until you build up airflow.
I personally like my ECU to use what's on the specific column for the TP I'm at, and not the right most column, thus I disable this for my NA and turbo bins.
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Please refer to the
Z32 ECU Tuning Guide for a more in depth descriptions of most of the tunable items
Beginners Guide to Chipped ECU Tuning
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Originally Posted by Calum
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