Project Glanza Running Well, fan then cut in now won't start

[paddy]

Right been working on a project glanza I bought from eBay, just put a low mileage gt engine it which hasn't been run for 6 years, cars been running and ticking over a few times now, ran lovely, just changed the exhaust manifold gasket started it up let it get warm for the thermostat opened, the fan cut in it then started spluttering so I switched it off now it won't start, anyone got any suggestions? there's a spark and cranks over fine just won't fire

[Ryncewind]

Is it getting fuel?

[paddy]

It's had a new fuel Pimp, tanks been off and blasted out with a jet wash, fresh fuel, new fuel filter injectors and fuel rail. Could this be a sensor of some sort?

[Ryncewind]

Is it actually getting fuel into the cylinders though?

[paddy]

It's getting fuel to the rail, the spark plugs are very black, I'm pretty sure it's getting fuel to the cylinders