After prolonged periods of sitting there are some preventive inspections / interventions are recommended:
- Checking the inner side of the fuel tank for debris / rust (small debris particles will damage the fuel pump)
- Flushing the old fuel out from the fuel system with fresh petrol
- Replacing the fuel filter
- Replacing timing belts (the rubber layers may suffered permanent deformation due the static load, and
might tear or jump during starting attempts or later when the engine is running)
- Checking operation of the injector valves (by supplying DC power to them one by one, audible click should be heard)
- Inspecting the inside of the distributor cap and the rotor arm (cleaning them if necessary)
- After the first successful startup replace the engine oil and the filter.
- Besides the timing belt the power steering and alternator belts should be replaced too, after the belts are off the water pump need to be inspected (does it turns freely, and there's no excess axial and lateral play of the shaft)
- It is also recommended to replace the engine coolant, as they tend to turn acidulous
If the engine turns over normally without abnormal noise, then probably there's no damage.
Sometimes the piston rings are get stuck, resulting low compression, and hard starting.