As expected, Grant's response is much better in detail.


The residue from my recent travails include some ignition switch parts. Not fun to remove and open, but, definitely doable. I did. Mine was a mess. Dirty and worn.
A fresh one fixed a lot of things.


In Jagspeak, brown wires are always hot. One or more go to the switch. In Jagspeak, solid white is hot with key on. Several of these leave the switch. powering several circuits, fuse boards, etc. One is to the coil + post.


As Grant says, there is the rub. it should be a nice healthy 12v, not a wimpy 7!!!!


So, when the ballast reduces that, he coil gets mebbe 3 or so. Nope, nowhere near enough to get a nice fat blue spark to "distribute" to the spark plugs. You seem to be on to that.


So:


1. Jump the 12v to coil post + to verify the hypothesis




or


2. Go right at it and remove the ignition switch for service or to replace. Caveat, teeny screw and little ***** to lose. How do I know.....




Stick with it, you are very close....


Carl

 

Now half awake.

The PreHE has a "Main Relay", and that is a Pommy term for Ignition relay. Its MAIN task is to switch ON the fuel ECU/Fuel pump/and general ignition systems. It is on the RH side of the radiator top support panel on those down here.

It is LUCAS, and would be in dire need of contact points cleaning by now. I reckon it is working, coz the pump is working etc, but a simple 40 year clean up will do no harm.

I dont think that relay has anything to do with the coil/ballast supply, its been a while, that is purely DIRECT from the ignition switch.

When you get that electrical section out of the mechanical section, place it INSIDE a plastci freezer bag BEFORE opening it up. That way the spring/pawl/***** will only fly around the frezzer bag, and even blind old me can find them. The shed floor is a LOST ZONE.