been wiring up my zetec,i came across a cam sensor,(above no 4 inlet port)cant find the plug on the loom that went on it and no mention of said sensor on megasquirt.....so do i need it?

Is it the zetec equivelant of the crank sensor? Or is there one of those as well?

there is a crank one as well,vauxhall have these.....but ive forgotten their perpous...awaits entry of ns dev

You only need a cam sensor for sequential injection, or Coil On Plug ignition, so the vast majority of megasquirt installations will never need one.

cheers mike.my injectors are wired in pairs (gixer) so i dont need it?

No you don't. Whilst megasquirt has two injector outputs that can be fired independantly, it's still a variation on batch firing, i.e. they are not synchronised to a particular cylinders firing stroke.

However,

If megasquirt can be tailored to make use oif the signal then sequential ignition should provide a useful gain in fuel economy.

I am not sure if MS can handle it though!!

It's a bitch when they go wrong though, as they tend to on some French models.

cheers chaps