I got this car of a friend very cheap when I start it first time glow plug light comes on and it over revvs for a few seconds . but if glow plug light don't come on it don't over rev
It will need to go onto a suitable computer to determine what faults are stored but be aware that as you said it is a cheap motor and any expensive parts/labour needed may not be worth doing.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix cars.