Tunerpro Fuel Mixture Settings: Where To Adjust For Performance

To change the fuel mixture in TunerPro, you will need to download the software and a matching set of Bin and XDF files. You will also need to download a Hex Editor. After opening the Bin file in the Hex Editor, you will need to double the code by copying and pasting it at the top. You can then open TunerPro, load the new Bin file and the XDF file, and set your injectors. You can then follow the steps in the source material to adjust the fuel cut setting, MAF multiplier, MAF scalar, timing, octane, and AFR tables. You can also adjust the fuel injector deadtimes, fuel trims, and MAF compensation.

Injector Deadtimes

Injector dead times refer to the amount of time from closed to open that a certain-sized injector takes to open under a certain voltage and fuel pressure. This is not a very important value in reality, as it is more of a "fine-tuning" aspect that helps keep a steady idle at night or when there is a load on the electrical system.

To get the injector dead times right, it is important to first install the app and ensure that your car is assembled, will start and run, and has a working electrical system. Next, get into the "dead time" or battery volt compensation map and zero all values, making sure you are at normal operating temperatures and zero out any air temperature or coolant temperature trims in these ranges while setting the dead times.

Get the car running to where you have the best voltage you can normally get, and then disconnect the vacuum line from the AFPR and plug the leak/hose to keep the fuel pressure constant. Set the AFR at this idle to something like 14.7 and adjust the pulse width for all the cells around the idle's current cell to the exact same value. At this idle, your volts should be at their best/highest average value, and make sure all electronics are off. Set the dead time (volt comp) in this area at a low even number and take note of the AFR.

Turn on enough accessories/lights to move the volt comp/dead time cell to its next cell over, and then increase the dead time at this lower voltage until you get the same stable AFR as before. Repeat this process for the next cell, taking note of the amount of pulse width/ms changed in the two cells you adjusted, and then average them out. Make the new value your initial full voltage dead time, and add the amount of values you got from the previous two steps to fill in the next two cells.

Repeat this process for the remaining voltage cells/dead time cells, and then hook your fuel pressure vacuum line back up. As for the values when fuel pressure rises with boost, this is what your pulse width takes care of.

In terms of where to change the fuel mixture in TunerPro, the software allows users to discuss anything tuning-related, including fuel pumps and injectors. Users can also download bin files and XDF definition files that identify where each parameter is located in the bin file.

Fuel Cut Setting

The fuel cut setting in TunerPro can be adjusted to prevent fuel delivery to the engine when certain conditions are met. This is typically done to protect the engine from damage. The fuel cut setting can be customised using the TunerPro software and a compatible chip burner or emulator.

To remove the fuel cut, you can use TunerPro's hex editor, found under Tools -> Advanced. You will need to manually enter the code for fuel cut removal, which can be found on hwnd.org. It is important to "save as" so that you can always revert to the stock bin file.

For Bosch (Porsche, BMW, Volvo, etc.) engines, the revlimit soft limit acts as a fuel cut. To set an ignition cut instead of a fuel cut, you can try retarding the ignition table and setting the ignition dwell time to 0. However, this may require further adjustments, such as disabling ignition secondary current monitoring, as otherwise, you may encounter coil fault codes and fuel cut issues.

MAF Multiplier

The MAF Multiplier is a crucial aspect of tuning, as it directly impacts the air-fuel ratio (AFR) and, consequently, the engine's performance and fuel efficiency. Here's a detailed guide on the MAF Multiplier, specifically tailored for the TunerPro software:

Understanding the MAF Multiplier:

The MAF Multiplier is a crucial factor in Mass Air Flow (MAF) sensor-based systems. It essentially scales the MAF sensor's voltage signal, which represents the amount of air entering the engine. By adjusting the MAF Multiplier, you can correct the MAF sensor's reading to match the actual airflow more accurately.

Locating the MAF Multiplier in TunerPro:

In TunerPro, the MAF Multiplier value is typically found within the software's tables or functions. It may be labelled as "MAF Multiplier for 2g mass" or something similar. The specific location may vary depending on the vehicle's year, make, and model, so it's essential to refer to the correct documentation or a trusted forum for your specific vehicle.

Calculating the Correct MAF Multiplier:

To set the appropriate MAF Multiplier, you'll need to understand the relationship between the MAF sensor's voltage signal and the actual airflow. Here's a general guideline:

• Determine the Target AFR: Start by deciding on the target AFR for your engine. For example, a common target AFR for optimal performance and fuel efficiency is 14.7:1, which represents a balanced ratio.
• Measure Actual AFR: Use a wideband oxygen sensor to measure the actual AFR your engine is running at. This will give you a baseline to work with.
• Calculate the Correction Factor: To bring the actual AFR closer to the target AFR, you'll need to adjust the MAF Multiplier. Here's the formula:

• For increasing airflow: Multiply the current injector size by the target AFR and then divide it by the new, larger injector size.
• For decreasing airflow: Divide the current injector size by the target AFR and then multiply it by the new, smaller injector size.

Apply the Correction: Take the correction factor and apply it to the MAF Multiplier value in TunerPro. This will scale the MAF sensor's voltage signal accordingly.

Fine-Tuning and Considerations:

After applying the MAF Multiplier correction, it's crucial to test the vehicle's performance and monitor the AFR using a wideband sensor. Fine-tune the MAF Multiplier as needed to achieve the desired AFR and ensure smooth engine operation.

Additionally, keep in mind that changing the MAF Multiplier only affects the MAF sensor's voltage signal and not the injector pulse width. If further adjustments are required, you may need to tune the injector scaling or pulse width separately.

Remember, proper tuning requires a comprehensive understanding of your vehicle's specific systems and careful monitoring of its performance. Always refer to reliable sources and seek guidance from experienced tuners when in doubt.

MAF Scalar

The MAF Scalar is a value used to keep the values in the MAF tables below 256 so that the values do not go out of range. The MAF Scalar is used in conjunction with the MAF tables, which are altered based on changes made to the MAF sensor. The MAF sensor calculates the amount of airflow bypassing the wires, which then causes the engine to lean out.

When the MAF tables are changed, the MAF Scalar must also be changed. This can be done by setting up the MAF Tables Conversion to be Y/256*X, with Y being "Other XDF Item Output" and "Choose Reference Item" being set to "Maf Table # (each table matches to each scalar) Scalar". This will automatically update each table's equation if the scalar is changed.

It is also possible to change the injector flow rate constants by a certain percentage, rather than adjusting the MAF tables and scalars. This method will not require a MAF recalibration, but the load (LV8 calculation) will not be entirely accurate.

Injector Scaling

It is important to note that when using significantly larger injectors, you may also need to scale the cranking fuel maps to prevent the engine from being flooded with fuel during cranking. Additionally, there may be other areas of the tune that need to be adjusted when changing injectors, such as dead time settings by voltage.

For those using TunerPro with a MAF-based system, the Injector Flow scalar can be found in the AFM Constant Map. For those with a VSII V6 Auto using TunerPro RT with the OSE Plugin, the Injector Flow scalar can be found by using the Ctrl+F keyboard shortcut to search for "injector".

For those with a BMW M42 318, the WOT fuel and ignition maps can be expanded by right-clicking and editing the XDF info.

Frequently asked questions