Can the oil sensor cause the car not to start

Not clear on your question but the crank & cam sensors if bad would not allow the engine to start.

Meant to say that i have changed oil pump, crank sensor & sub-block as well as top gasket, but my car wont start. What could be the problem?

Spark plugs smell of petrol but when i feel it it is cold. It feels like it is not sparking

But the way it is a 2L non-turbo

Then you have to verify that there is no spark, then diagnose the ignition system. It could be a number of things.

It does crank though. How do i verify that there is no spark? Which sensor actually causes the car to spark?

You have the coils that could be tested, ignition control module which can be tested, if the crank and cam sensors are bad then the coils will not discharge its spark, all assuming all the wiring is good.

Thanks, i'll test it later on

Best option is to replace coil pack/spark plug N camshaft sensor...the sensor should be below oil filtet, if u cant see/find remove coolant expansion tank for more room then on the wall u should see 5 different colors N u want to follow the grey one all the way down N u shoul find i...it bolt in with a screw N its hex key forgot what size... Good luck