Hello again guys. Further to my earlier posts in Members Questions re: my 2006 l200 k74 starting up no problem, revving up for a second then shutting down. Sometimes the engine management light comes on, other times not. The fault code that sometimes occurrs is 21 NE Sensor (main). This I believe is the crank angle sensor. This was replaced with a new reluctor blade as well. An instant before the engine dies it revs up for a split second, the rev counter then drops to zero followed by engine shutdown. Today on about the sixth start the engine continued to run at a smooth idle speed but with the rev counter reading zero. The engine would not rev up however. So (at last) to my questions: What powers the rev counter and gives the ecu its required information? I had previously tried disconnecting the speed sensor? on the side of the injection pump and the rev counter still worked. Does the ecu have two engine speed inputs? My brain is beginning to hurt. Any help much appreciated.