The detection of gravitational wave GW170817 along with the electromagnetic counterparts has open up the speculation of the existence of quark matter in neutron stars (NS). There is a hint that the collapse of two NS to ultimately a black hole happens via an intermediate step of nuclear to quark phase transition (PT) in them. However, the GW signals coming from a single rotating NS (pulsars) are still beyond the scope of modern GW detectors. However, if there is a phase transition in NS, then the GW signals can get quite intense. In this talk, I will present the prospect of such PT from nuclear matter to quark matter in NS and the possibility of GW signals coming from such PT. The nuclear quark PT is assumed to be a shock-induced PT or to say combustion. Such combustion hints at the existence of a maximum mass in the QS. Such burning is accompanied by a strong GW signal with timescale smaller than GW170817.