This shows the intank.
the e30 has two fuel pumps, one intank on the fuel pickup and one external.
The external is the main pump and is the larger of the two.
Here is a diagram of the fuel pump control.
Fuse #11 is the primary fuse.
Shorting the pin 30 to pin 87 on the fuel pump relay will bypass all controls.
Fuel pump relay is outside the fuse box and the wires to it are the
Red, Red with white stripe, Green with Violet stripe, and Brown with green stripe.
If the pumps work with the fuel pump relay bypassed the issue is a fuel control signal.
There are a few things in that circuit.
Fuse #21, OBC relay, Main relay, and the ECU signal.
I hope this helps,