Hi P
Hi Psi it is used on all throttle application (sudden throttle application) and sometimes can be a tedious process, usually and I say usally above 4000 rpm no throttle pump is needed or very little is need and as we go backwards down the RPM range more is needed .Some widebands can capture it depending on how quick they respond and positioned in the pipe the closer up,front the better.
And like someone has mention just previously it's like the accelerator pump on a carby if you look down a carby you will see the pump squirt fuel down the throat same principal accept in the EFI world that figure that's inserted in transient pump is then added to your base iIDC. Hope this helps a bit