The ECU will increase the injector pulse width based on the AFR target, fuel trims, other run time variable parameters, and environmental conditions. This is NOT the actual injector pulse width. Base fuel schedule is the theoretical pulse width that the ECU would have to run in order to maintain a 14.7 AFR. The BASIC formula is current MAF value times K value = BFS. This is the multiplier that the ECU uses to determine the base fuel schedule (BFS). Increase the values to richen the AFR and decrease them to lean out the AFR.

This is one of the tables that you will use to correct the AFR so that the ECU hits the AFR targets that you are telling it to hit in the Fuel Target table. Above 100 is adding injector PW, and below 100 is taking injector PW out. Once the coolant temperature gets up to 80 C, then the ECU will switch to the Main table.įor both tables, the values represent a change to base fuel schedule (BFS) as a %. This table is only used when the vehicle is still in warm up stage. Fuel Compensation Main is the primary table that every ROM uses.įuel Compensation Cold is only used on some of the newer vehicles. There are 2 types of fuel compensation tables to be aware of depending on what ROM you are working with. X – Axis = UNKNOWN theoretical value Y – Axis = RPM It should hit new targets with little to no tuning once the other fuel parameters are dialed in. Once you have the fuel compensation and MAF curve tuned so that the ECU is hitting the targets you’re telling it to hit, then adjusting the tune to run new targets is as simple as changing this table. If you try to adjust this table to get the ECU to hit a desired AFR, but that AFR is not what you put in the target table then the ECU will trim to the targets you’re telling it to hit instead of what you’re tuning it to hit and it will likely throw bank rich/lean DTCs.

You should be using the fuel compensation table or MAF curve to correct the injector pulse widths so that the ECU hits the targets you’re telling it to run. Once the table is setup the way you want the car to run there should be no reason to adjust it again. This table should be set to the AFR targets you WANT the ECU to run. The values in the table tell the ECU what AFR target to try to run. X – Axis = BFS (theoretical injector PW), Y – Axis = RPM The “MASTER” ROMs are the ROMs that overwrite any older versions. Then reference that number against the “ROM Support Matrix” which can be found in the UpRev directory or under Start > All Programs > UpRev > ROM support matrix. To find out what ROM should be used on a given vehicle, check the ECU part number with any of the UpRev software. Keep in mind that some ROM versions have parameters that other ROMs do not.

Nissan altima ecu tuning