Thanks Tony, I have checked for the signal down to 50mv/division,if i wiggle the wire sometimes i can get a signal of 100mv-negative 100mv(200mv amplitude),but most of the time there is nothing although there was when i first tested it.The resistance measures 4.9 kilo ohms.I still can't see why the rev counter works & the timing is ok & then it isn't even with the lift sensor not working. Regards, Andrew