Thanks Steve,
Frequency valve is buzzing, someone suggested low fuel pressure on The MBZ Discussion list, I will check that monday, I read somewhere that volume could be checked by disconecting the fuel return hose at the distributor and running a hose into a container and measuring the volume for a specified time, Monday I will try to look that up, you don't happen to know do you? Or maybe what the fuel pressure should be at the distributor? Thanks phill