EKB18BPR3

hey i just built my car and it cranks but wont start. well its narrowed down to spark or fuel. i got the spark tester from autozone. so checking for spark is no problem. but checking for fuel is another story. the guy at autozone said i if i dont wanna make a mess with fuel all over the motor for unplugging the fuel line and turning on the car to see if fuel flows, i can spray fuel injector cleaner into throttle and see if it fires up. if it does than its a fuel problem. has anyone ever done it this way to check for a fuel problem? is it healthy for my car....i dont really like using additives and all the cleaner stuff.