If as your post says this is an Hdi you can't adjust the pump manually it has to be done electronically by changing the mapping. The easiest and cheapest way to do this is to fit a tuning box.
PeterN wrote:If as your post says this is an Hdi you can't adjust the pump manually it has to be done electronically by changing the mapping. The easiest and cheapest way to do this is to fit a tuning box.