Bryan,

My "hands-on" time has been almost exclusively 240. And though much fuel and ignition stuff is shared across all 3 platforms, I think it's not the same for all years. That is, I think your '88 740 may have the LH 2.4, which didn't get to the 240 till '89. Best I can do for openers is comment on parts of your post that caught my nit-picker's eye, and offer a rare but recent and personal 240 failure that shares your symptoms (but maybe not the cause, however).

"This what I have swapped out with my 90 744ti, , power stage, fuel pressure regulator and coil."
• Terminology? I'm guessing your "fuel pump" relay is my "Fuel Injection" relay. The white one that powers the pumps, and much more: AMM and ECU for example. Your FI relay? Maybe the "Interference/Radio Suppression" relay in the engine compartment?

"The fuel pumps do not come on when the key is turned on but they will come on when the relay is jumpered. The engine will not start with the relay jumpered."
• I don't know just how you "jumpered" the relay. It has two critical outputs. The pumps are just one of them. You're saying the pumps aren't the main issue, right? You can force them on by jumpering the relay, but still no start. Give me "jumpering" details please.

"I am getting fuel pressure at the rail."
• "Residual" pressure (from when the pumps last ran) can be misleading.

"I am getting 12 volts to fuse 11(I checked the correct fuse but..."
• Fuse 1 is the main FI fuse, #11 is for tank pump. Do you have any wiring diagrams?

My recent 240 failure was the FI relay, but in a way I've never seen -- or heard of here. That white FI relay is really 2 relays in one package. The "Main" relay comes on with Key ON, to power the AMM and ECU. It also puts power on the Fuel relay coil. But it's up to the ECU to energize the Fuel relay by giving its coil a ground (as with injector control).

The ECU can ground the Fuel relay at Key ON (LH 2.4 only -- 2.2 doesn't do this) to "buzz" the pumps. And then during cranking and running, but only if it gets timing pulses from the Ignition CU.

However, none of that will happen if the first relay (or its output terminal) fails -- no AMM, no ECU, no power to the fuel relay. You can "force" the pumps, but without the AMM and ECU nothing happens.

That's what happened to our 240, and it was a "first" for me. We had to jumper from the FI relay input (terminal 30) to BOTH outputs -- 87/1 for the AMM, ECU, Injectors, Suppression relay, etc., AND to 87/2 for fuel -- the usual suspect.

On your car, I think you can check for voltage from 87/1 (Key ON) at AMM pin 5 or RSR (Radio Suppression Relay pin 2. It should be a blue/yellow wire if colors were constant over time as in 240s. My diagram is for the '93 940.

Sorry for all the rambling, but this is sort of a fishing trip at this point.

--
Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.