Another more advanced form of fuel volume function monitoring is the reverse pulse check map. This map has a maximum upper limit for injector opening time on the Z axis with axes of engine speed and Rail pressure. This map is very smart and picks up on two things.

1. If the tuner has incorrectly adjusted the injector calibration map to trick the ECU in to adding more fuel then this map will detect it and put the car in to limp mode.
2. If the injection quantity is increased quite a lot, or this map is set very strict from the factory then the ECU will detect increased fuel flow and then put the car in to limp mode.

The solution to this map is very easy, you simply need to check your injection durations for all requested fuel quantities in the remap and adjust this map accordingly, and of course never adjust the injector calibration map!

Part 4 – Lets talk tuning protection