Need to release the pressure in your 300ZX’s fuel lines? You might want to do this for a number of reasons, such as changing out the fuel filter or removing the fuel injectors. Without releasing the pressure between the fuel pump and those items you will have a spray of high-pressure gasoline when you try to take the first hose or injector off – which is not just inconvenient but potentially dangerous. The techniques below may not completely remove the pressure, so it is wise to take all necessary precautions against spraying fuel – wear safety equipment and remove any connectors with a rag surrounding them to reduce the chance of fuel spraying somewhere you don’t want it to.
Essentially what we want to do is to disable the fuel pump and crank the engine, drawing through any fuel in the fuel lines and removing the pressure. You could remove the fuse which protects the fuel pump, or unplug one of the connectors in the boot/trunk underneath the carpet:
Disconnect the blue connector:
Now crank the engine – you should see it fire up for a second or so before it dies. Crank it briefly a couple more times to try and get any remaining fuel out of the lines and you should now have released the pressure as much as you can.