sixto, everything checks out fine with the glow plug system.

Very hard to start again this morning but once started restarts are fine. Lots of smoke coming out of exhaust when it's trying to start which indicates to me that fuel is not a problem.

I'm wondering if there is another cutoff circuit in the iginition chain somewhwere that may be acting up?

I tried replacing the glow plug module with a second new one and it behaves the same. I do notice that the new glow plug module has a soft click to it when the ignition is turned on whereas the old module had a very distinctive hard click sound?

Any ideas?