So I bought a 91 300ZX for $400 and came with the engine and trans, but obviously it being a project car, it don’t start. We changed the Starter, new Fuel Filter, and brand new NGK Spark plugs. Also, the fuel pump and the fuel sending unit was HEAVILY corroded with rust as well as the tank, so I threw both away. What we’ve tried doing is feeding the fuel (gas) thru the fuel filter and through the 2 fuel lines to see if it can start, but obviously nothing. I’m wondering, will I need the fuel pump and fuel tank in order for it to turn on, or will I need new injectors or other miscellaneous things? (Water pump, timing belt, gaskets, etc). Also, when I try starting it, the MPH needle vibrates a lot instead of it being still. Any help is greatly appreciated

Whooooo.... Welcome aboard.

You've got a lot going on there. First off, you're gonna need the tank and fuel pump, because it's a closed, pressurized system. It's not carbureted, so unless you have a way to pressurize the fuel line, you're wasting your time.

Second, if the tank and pump was shot, the sender is probably crap, as is the pressure regulator, the injectors, and most likely the rail.

Yes, you'll want to go through all that other stuff, but you need to know if the engine is even worth saving - Compression test would be first on my list.

You're not ready to try and start the car - One step at a time, starting with a compression test, followed by all new fluids and filters... then you can start thinking about fuel delivery,

Thanks! And thanks for the reply! Yea I was going to check the compression later this week. Do you know whats the best compression reading for a VG30? And I figured I needed the tank and what not as it’s pressurized. We also changed all the fluids in the car so it’s why we tried giving it a go.

Use the factory service manuals provided on this site, its at the top of the page. The Z32 manuals are very comprehensive.

UPDATE!

So some times has passed and I was able to do ALOT to the engine. I took the timing cover off and noticed the Timing Belt was WAY OFF! So I bought a new timing belt and fixed the timing. Also replaced the Fuel Pressure Regulators, new hoses all around, new thermostat, new tensioner pulley (I snapped it lol), all 3 new belts, new gas tank, and a new radiator. So I basically need a Fuel Pump and Fuel Sending Unit and hopefully after that, it should crank. Also, the 6th cylinder is at 125psi while all others are at 190psi. My goal is to get it running so I can take it to a Autoshop that specializes in this car (found one near by) so they can run a diagnostic and see what I else my Z needs replaced

Be prepaired that #6 piston hit a couple of valves , "timing way off" , it's an exhaust valve I believe when timing cams become way retarded due to slippage you mentioned.This the #1 thing to check on,good luck.
A situation like yours a "project car" , you don't need it by Tuesday , and we all see so many get a car and be anxious to hear it run , anticipation does this to us. But a "mystery motor" - if you can/want to - do a FULL and thorough timing asessment . Manually turning crank slow to feel compressions and both w & w/o plugs , and most importantly GET ONE TIMING COVER OFF and examine . Bent valves in the least is head job,and who just does one side ? or now continue "busting down " into block at that point.

About the only positive in that scenario is a complete rebuild done completely ?

If the valves hit on number 6 compression would be even lower, or non existant, more than likely it's just from the usual issue of number 6 having lower compression because of casting flash in the block