New to this,got Astra van 1.7dti 16v it's on a y reg. engine management light is on OPCOM reads no rpm signal,spill valve relay stuck closed and glow device voltage low.first thing I changed was the crankshaft sensor which I was hoping would sort the no rpm signal out but it didn't,plugged OPCOM back in and the no rpm signal was still there and wouldn't clear. Second thing I did was change the edu for a different one as I've read the edu are common for solider joints and cause the spill valve relay to get stuck closed,since changeing the edu OPCOM diagnostics won't work on the van (tried a different diagnostics kit but that wouldn't work). Since the van has shown these fault codes it still runs fine apart from a little flat spot in second gear. Mot is due soon and I'm completely stuck on what to try next.iv read when the injector pump is on its way out there will be like a knocking noise and it will puff a bit of white smoke,my van has these symptoms. Is there anything else I can try or change before I buy a injector pump?