1991 Nissan 300zx will turn over but will not

According to OBD standards it should be reachable when you are sitting in the driver seat. Since it is made before 1997 it is a OBD1 not OBD2 connector.

the ecu is located behind the passenger kick panel , there is a little window at the top of it which has 2 lights in it red and green, turn the key to the on position, do not start engine, push gas pedal all the way down then release, the lights will start blinking, for example if you get 3 green blinks and 2 red blinks that means code 32, 5 green and 1 red code 51, there is a list on the front of the ecu that tells you what each code means

not that i remember

try partstrain.com, they claim to have it when I searched.

Check brake fluid level , if low will turn on light when brakes pushed.Dash lites is possibly a fuse or turned off on the dash.

open the valve cover and feel all your lifters to see which is loose.

spin your push rod with your fingers while tightening your rocker arm(should be 5/8) once you can not spin the push rod any more give it 3/4 of a turn and your good to go repeat for any loose rocker arms.

If you are telling the compression it fine i advice you to to put new spark plugs then see what it gives,then you will know what step to take after ,hope that help you and solve it.

if they have marks, you just need to rig up a tool to turn them untill they line up, turn them the direction they rotate when running, be easy as not to damage the sprokets...

first here is the service manual http://www.300zx-twinturbo.com/cgi-bin/manual.cgi

next is the kick panel http://209.85.62.26/12640/0/upload/p979648.jpg

These should be right or very close .

If the car idle on high rpm check if when you will step on the gas pedal over 2500 3000 rpm the car will start shaking and the will die if thats happening then check your mass air flo sensor ,or if there is no air leak that avoid the mass air flo sensor