I'm not entirely sure as there may not be a widely known 'Pump Fiction' in mainstream media. It could be a very specific or indie creation. Maybe it's a story about something related to pumping, like pumping water or gas in a fictional and creative context.
I haven't heard of 'Pump Fiction' being a widely recognized book or movie. It might be a self - published book or a very low - budget independent movie. Without more information, it's difficult to say for sure whether it's a book or a movie. However, if it's a story - based work, it has the potential to be either medium depending on how the creator chose to present it.
It could be that 'pump it up' is used to describe the way the 'pulp fiction' elements are presented. Maybe it means to make the pulp fiction more exciting, like pumping up the volume of a story. For example, increasing the action scenes or making the characters more flamboyant.