my 95 escort is consuming too much petrol and had black smoke and just after engine overhaul why?

The engine could still be getting broken in, that should last about 500 miles then clear up

If it doesn't clear up soon, check if air cleaner is clogged. Black exhaust smoke tells me excess fuel, not enough air. Being a fuel injected engine, I'm thinking excess fuel pressure. Have it tested and scan for problems with fuel regulator and fuel pressure sensor. These pre1996 cars take an OBDI scanner for codes. Ask your engine rebuilder what's going on. Excess fuel pouring into the engine can wash the oil down and ruin the rings and cylinder walls.