Cosworfh

Can somone please explain if the live feed on the ignition coil is switched through ignition or is this a permanant live to the battery.

Basicly i'm fitting a YB lump into an E30 and need to understand how the ignition system on the rwd wiring functions where does it get power from and what triggers the spark. Also on sierras is the rev counter get the input signal from the negative of the coil?

tabetha

Tacho does indeed feed from the negative of the coil.
The positive of the coil comes from the main control relay(pin 87) which also feeds the fuel pump relay, this feed goes from pin 87 to pin 4 of the TFI module(ignition module and also branches off to the coil +.
Hope this helps, it doesn't have to be as ford did it so long as it gets feed etc then do whatever is the easiest way.
tabetha

Cosworfh

How do i identify the main control relay? does this relay have a permanant live to the battery and the fuel pump relay where is it located or how do i identify it.

Does the coil have a permanant live via the main control relay and what does this TFI module actually do?

tabetha

The TFI is ford speak for ignition amplifier, it does what it says on the packet, pm me your email addy and I'll pop a drawing in the system for you.
tabetha