I ve been trying to start my 86 rx7 and today i was trying to start it but this time i unpluged to fuel pump and i crank it and sounds like it wants to start but it cant because its not getting fuel but i hear it popping, and when i plug it back in the engine just spins but not start i dont know what it is because when i crank it i hear the compression of the engine. If there is anyone that can help respond thanks...

 

Maybe you have bad fuel. asssuming it wasnt doing this before.

 

the fuel is a few months old and i have pre mix in the gas would that also make it harder to start