It's never the coil

[svenedin]

Sometimes some of the wire strands captured in the crimp connection fracture but the actual spade bit still makes a tight connection. That’s even trickier to diagnose. If in doubt and you have the tools anyway, crimping on a new connector is easy to do. Usually affects wires subject to high vibration (such as the dynamo mounted Morris coil).

[geoberni]

Sometimes some of the wire strands captured in the crimp connection fracture but the actual spade bit still makes a tight connection. That’s even trickier to diagnose. If in doubt and you have the tools anyway, crimping on a new connector is easy to do. Usually affects wires subject to high vibration (such as the dynamo mounted Morris coil).

Try finding a fault where someone has crimped the insulation but not the conductor.....

[stuffedpike20]

The car in question is notorious for having a delicate wiring loom.

Thanks.

[stuffedpike20]

I would suspect a Hall Effect device to be the most likely culprit - assuming, of course, that it is an ignition fault.

And the winner is...........oliver90owner!

I thought I had diagnosed the problem as a loose wire on the coil.

Conked out today and waited for the AA. It turned out to be......the Crank Sensor.

So on a 31 year old car; it's never the coil, and probably always the crank sensor. Well done oliver.

Thanks everyone.

John.

[keith rogerson]

1987 in my third Mog, a lovely convertible, I happily drove through France in to Italy, and back home.
Not one problem even after 4000 miles, same engine and gearbox etc since it was made.
I had that particular mog for 25 years.
I'm hoping with my latest mog Wilf, a new coil is going to be the solution and another solid 20 years of mog motoring.