Pressure has nothing to do with the fuel pump turning off when you turn on the key. It is on a one second timer inside the computer.
Note that one second is longer than most people think.
The computer has no idea what the fuel pressure is at any time as there are no pressure sensors in the fuel system or pump.

 

You also need to see what codes are in the computer memory and see if the truck passes the electrical KOEO test.
Note that the computer memory (CM) will be cleared if the battery is disconnected.

 

The red wire is common to all fuel injectors and also the fuel pump relay coil along with the computer power. So the EEC Power relay is supplying power to the red wires as the pumps run with pin #6 grounded.
Sounds like you have some open wires on top of the engine as the red wires should be hot all the time the key is on. The computer grounds the fuel injectors to fire them.

 

Should fuel pump run all the time when pin #6 is grounded and switch is on? Note check engine light never has been on except when I grounded #6

 

Yes the fuel pump should run all the time pin #6 is grounded and switch is on.

 

How do I read the codes can it be done without a scanner

 

Koeo Elec test how do I do that

 

In post #19 above shows the self-test connector that has pin #6 in it. You can use that connector to count the flashes or you can use the CEL in the cluster to count the flashes of the codes.
Just ground the STI wire and turn on the key with the engine not running and count the flashes of CEL or test light. Make sure you get a paper and pin before starting so you can record the flashes.

For more information on reading the codes go to this link:
Fuel Injection Technical Library » How To Run a Self-Test

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The KOEO Electrical test is the first set of codes that are read out. Then there is a space (one flash) and then the CM is flashed out.

 

Guess I'm too slow this morning.

 

Ok thanks. Did grounding #6 and fuel pump staying on confirm computer is good

 

No it bypassed the computer for the fuel pump test.

 

Sti wire is located where?

 

The STI wire is the gray one wire plug that is setting on top of the red self-test plug in post #19 above.

 

Did self test showing codes 21 63 24 34 85 most relate to voltage of certain components