can anyone please help me, ive not got a clue when it comes to cars, i can tell you the problem and put some pics on here and see what people think (who know what they are on about)

its a 1.7 td astra 1999

there is diesel squirting out of what looks like a connector on the right hand side, i dont know what they are called, there are tubes connecting the first to the second, the second to the third and third to fourth, but the connector on the fourth is open and squirting diesel

can anyone let me know what is supposed to be on this connector please....