WIBIMMERS

Am looking into a buddies 92' 325i with 97 S50B32 m3 engine swapped in that he wants to sell, it has low miles on both car & new engine as well as the m3 quad exhaust installed & a new fuel regulator however the engine shuts off after 10 mins & won't go back on for 30 mins after that?? Could this be an oil pressure/temp simple fix or something much more expensive? As far as I know the engine(under 60k miles at swap) was in great working condition at time if swap(or else he wouldn't of bothered w the project) any advice or info would be greatly appreciated... Btw I do have experience & have rebuilt e30 engines from scratch so I'd it were simple it would be possible & worth it for me as he only wants 2500$ & the car itself is beautiful w all aesthetic m3 parts added.