This engine has a mechanical fuel pump.It is mounted behind the carburetor below the valve cover .It is very close to the firewall with the fuel line going to it.You will have to remove the air cleaner housing to access it.It is about the size of a tennis ball and goes into the valves area which operaterates it.
IT'S LOCATED ON THE PASSENGER SIDE OF THE HEAD AT THE REAR OFF THE MOTOR UNDERNEATH THE AIRCLEANER.
There is no "reset" switch for the fuel pump on that vehicle.
YES it will fit right in. But now hears the problem that you will have. The 91 is a fuel injected computer controlled engine and the 86 is not. Therefore you would need the entire wiring harness and computer plus the fuel pump that's in the 91 fuel tank. You will run into all kinds of problems trying to get the 91 engine to run in that 86 truck. It would be cheaper and easyer to get a carburatored engine and put it back in the 86 truck.
If the engine is fuel injected, it is an electric pump and is located in the fuel tank. If not, it is located on the engine block and is a mechanical pump.
You may have a bad fuel pump relay or a blown fuel pump fuse.
Under the hood, on mine.
the 1986-87 lg4 engine had a mechanical fuel pump and an electric in tank pump.
The 86 has a mechanical pump. There are no electrical connections.
If the inline fuel pump can deliver a constant 9 to 13 psi it should work. Wire it to the original fuel pump wiring harness and mount it as close to the fuel tank as possible.
GM vehicles do not have a fuel shut off/inertia switch
Mounted on top and inside the fuel tank.
Most likely