Hi Eric While trying to troubleshoot my problems last week, the frequency valve was one of the things I looked at. Having a "spare" DeLorean next to mine made this sort of thing beautifully simple :-) One of the things I did was put 12v across the valve and check that it clicked. With no voltage, there's no flow through the valve (was blowing air through it), with 12v across the terminals, air flowed (slightly). Therefore the signal is generated elsewhere - I would be very surprised if it doesn't run on 12V and certainly 0.5v sounds very low - who can confirm? It sounds like you're using the scope correctly - if you can wait for a week or two, we'll scope up the signal on mine. (disclaimers apply!) All the best Martin #1458 www.delorean.co.uk Eric wrote: > Does anyone know what the VOLTAGE going to the frequency valve should > be. >