I was trying to massively increase the amount of fuel injected during overrun (when very little fuel gets injected). Using the scalar meant that I had to make the injectors seem much smaller than they are (for example up to 8 times smaller) so that the ECU would increase the injector duty cycle. However the existing value for the injector scalar is about 1/2 the maximum possible value, therefore I couldn't increase it by more than about 2.
What you see in Romraider is the inverse of what's in the ROM, therefore bigger injectors mean a smaller raw value in the ROM. The above would only be an issue in normal usage if someone attempted to use 200cc injectors, which will definitely never happen.