If it's a N/A with Bosch pump
N/A = normally aspirated (Non Turbo

)
Looking from the front, the adjuster is on the left hand side of the pump. it is adjusted from the back of the pump under a tamper proof cap (if still in situ). undo locknut turn clockwise slightly to increase revs.
For a quick bodge fix you can tighten the cable adjuster where it fixes to the timing belt case