Sounds like 2 different problems:
1) FI operaton for start/run (No-Start)
2) FPReg for "residual" pressure (Not a no-start problem)

"now it is totally dead,spark is there but no fuel comming from pump(regina).replaced pump still won't start."
• Spark but no pump usually means a Fuel relay (or pump/wiring) problem. Was the relay you put it a new one? Or tested in another car? Fuse 1 should be OK, unless it got blown while you were forcing pump to run for pressure test.

Relay or fuse1 are the 2 obvious trouble points for pump problem. Only other thing I know of (saw once here in 5 years) was Item 2b in my other post—where ignition signal didn't get to Regina ECU, so there was no Fuel operation. That was a bad wire from Rex (left side) across car to Regina (right side). Worn bare wire shorted the signal to ground I think.

"fuel pressure reading about 43psi when relay energized(shorting pin 30 and 87/2).as soon as i disconnect the short (pump off) the guage drops back to zero."
• That means 2 things to me -- and neither one related to no start as far as I can see. 1) FP at 43psi means the FPR is regulating pressure like it should. 2) Fast falling pressure means bad FPR (not holding pressure), leaking injectors or leaking Cold Start Valve (can't tell if you have one without knowing car year).
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Bruce Young
'93 940-NA (current), 240s (one V8), 140s, 122s, since '63.