I know this thread is a bit old but the PCU(Pump Control Unit) on top of the tddi injection pump is NOT sealed and can be repaired. I know i have had mine done for a £100 +7.50 P&P
Plus if you take the PCU off and send it off to him for repair, there is no need to reset the timing , i removed and reinstalled it in 15 minutes and it started first time
He does all makes and models his ebay id is twardyp