Hi I dont know if anyone can help< my son has had his yb cosworth engines head rebuilt the vehicle all runs now but it has gone for an MOT and failed on emmisions, to much co2, it chuffs out black smoke and the plugs are sooted up when removed, have put new plugs in they soot up as well, have put in a new ect sensor but no joy,the temp gauge moves straight up to hot when ignition key is turned on with the engine not hot or running with the old sensor and the new one and with the wires of the sensor all together, this conversion has been put in a van anda very good job but dont know much about them myself, any ideas or what I should be looking at?