Why would my fuel pump only be getting around 9 volts? The fuel pump relay is working fine. It was blown across the coil but I've replaced it and I hear it click. When I check for power at the pump I have around 9.5 to 10 volts. Pump is not on. Looks like a new pump but has been sitting for over 10 years not running. Even if the pump is bad, shouldn't it still get 12 volts? I haven't tried jumping the pump to force a 12v source to it just to see of it makes a noise. Kinda worried I'd blow a fuse or link or something.

 

I'd disconnect at the pump terminals and do 2 things to figure out the problem.
1. Measure the voltage on the disconnected wires. Is it 12V? If not, problem is between there and the battery. If it is 12V then do #2.
2. Apply a known good 12V to the pump. Does it pump? If not, it's the pump. Is it pumps then I'd suspect the connections to the pump. Make sure you clean and ensure good contact.

 

Start tracking the wires back to the power source. Always start at the problem, the fuel pump. Leave it connected with the key on and work your way back to the relay. This could be a dirty relay contact or a cheap poorly built relay or a bad connection in the fuse block. You don't say what year your car is and there are difference in the years.

 

Sorry I thought it showed under the 1981 280zx turbo thing. The relay is brand new i checked it with a multimeter the old one showed out of limits on the coil so I knew it was bad. The fuel pump control thing above the computer only give it a ground so if the power is coming from the relay and in the trunk and then down the ground is there due to the voltage showing across the wire it must be resistance somewhere not allowing a full 12v. I have a new pump coming today I will install it and see if it wasn't just old gas clogging up the pump making it not come on.

 

Update. After snapping off the fitting in the inline pump engine side and having to replace it i now have a running engine. When I try to give it gas it shuts off but it runs idle just fine at 38psi fuel pressure and I have a leak where the fitting goes into the pump. Scared ill break the only fitting I have left. Now I need to find out why it shuts off when I open the throttle.

 

You will need to do some diagnostics. Check the TPS for correct function and make sure you check any and every wire connection for green corrosion. Corrosion is a voltage killer and it is VERY common on your car. None of the electrical connectors are waterproof so the moisture in the air causes the corrosion.
You will also want to check the AFM and its connection and check the rubber boots for vacuum leaks especially on the boot between the TB and the AFM.
The diagnostic procedure for your car is in the FSM.
Free here
S130 FSM