1992 Vectra A 1.7TD ISUZU Why does the fault not light up 

That engine has no ECU so the fault light is dysfunctional in the diesel versions. It's only for EFI petrol engines.

you need to put a little bit oil because its low

Hello, the engine of my car is a 1.7 turbo diesel Isuzu engine, it starts late. after starting, when I turn it off, after waiting for 20 minutes, it starts late again but when I turn it off and don't wait too long, it starts quickly within 5-10 minutes