Hi all

A while ago our cab had a faulty electric fuel pump so we changed it for a new one. When it was fitted this started playing up so we suspected the wiring.... We have wired the pump direct to the 12v on ignition and now it pumps the fuel ok, but the engine idle is now all over the place...mainly running very high. Id like to put it back to the original way but the wiring is butchered.
Can anyone help with what I would need and maybe a wiring diagram for plumbing it in as the engine idle is just ridiculous.

Many thanks in advance.
Nick