I have got a s2 rs turbo with zetec turbo so running coilpack. I just fitted a aftermarket rpm gauge and I've switched it 4 cylinder on back of gauge and I've run the signal wire to the one on the wires on plug on coilpack. The problem ice got is when car is started the revs start at 8k any ideas why thanks

 

If you rev it does it move? If so it may need a resistor. If it doesn’t move then I suspect you have connected it to a constant positive.

Can you not ask the manufacturer tech dept?

 

Yes it does rev higher. Aftermarket rpm gauges shouldn't need a resister

 

If you're on a coil pack, the gauge probably need switching to 2 cylinder as it will be running wasted spark and triggering the coil once per crank revolution rather than once per two revolutions.

 

Ok I will turn it to 2 cylinder and see if that works. It won't make any difference that I've wired 3 other gauge together using the same live feeds and earth will it

 

That depends on the signal that it gets.

I had a webcon ecu on a zetec in a kit car and I had to use a resistor to make the aftermarket gauge stop reading half revs.

 

I've heard about it when it reads half but mine is at 8k