Hey guys, I am restoring a 74 450sl that has been sitting in the previous owners garage for a few years and i unfortunately cant get it to start

So far I have:
compression test (good compression)
new spark plugs
new spark plug wires
new fuel filter
new fuel pump relay
new working fuel pump (tested connecting directly to battery)

When i turn the car to the second aux position and starting I dont hear the fuel pump turn on for a second or at all and the car just keeps cranking and cranking with no start. i sprayed some starter fluid into the intake manifold and the car actually started for a second so i know i am getting spark. is there more than 1 fuel pump relay?

also some issues i noticed are

1. the tachometer goes straight to 7k rpm and stays there when the key is switched onto aux.
2. when you turn the key to start the engine the key stays there and the car keeps cranking if you let go of the key. its like the spring in the ignition tumbler spring broke which after starting the car puts the key back into the aux 2 position.

could either of these known issues be affecting the fuel pump circuit or show signs of a short?

here are some pictures of my fuse box and relays

I assume the box with the orange circle sticker is the fuel pump relay as its the only relay with 6 pins, all the other ones are 5.




here is the new relay i installed. I dont feel it click when i turn the aux on when connected to the orange circle 6 pin connecter but when i connected it to one of the 5 pin terminals and i felt it click with the ignition


heres a picture of my fuse box



and here is a pic of the 450sl i am restoring for my mother.


and here is a pic of my other cars/projects





thanks for the help in advance guys

 

Unplug the fuel line from the fuel filter to the engine (be careful - the system is pressurized and gas will spray out when you remove the line). If the line doesn't have pressure then most likely the fuel pump is not drawing from the tank, or the filter is plugged. Could also be other simple issues with the fuel injection like a plugged return line. Consider draining the tank of the old gas (just unplug the line to the fuel pump) as your tank may be full of crud.