Hello from Spain, and sorry for muy bad English.

I supose this it's an usual problem
I have a 3.1 1990 Firebird, that have been stopped 2 years, I only move it some kilometers this year. Last month I wanted move it, buy it didn't starts. It cranks, but nothing happens. I didn't heart the fuel pump the fisrt seconds. I proved with cold starter spray in the air admision and he want starts, but it's not enough. The fuel pump fuse under the wheel stering it's OK. I think the fuel relay near the windshield it's OK, and I have changed with the acondicionated air relay too.
The fuel indicator in the dash was in the middel, and 3 liters more. The day after the fuel arow indicator level , was on top, full.

The fuel pump conector under the car have 3 wires. With the switch ON betwen the black wire and the brown ( I think the fuel sensor level ) I real 6.5 V. And betwen black and yelow ( I think fuel pump switch ) I read 0 V. If I connect the black and the yelow directly to a 12 V batery the pump works ? I have an old pump and I try it, but nothing happened.

To the fuel pump relay arrives 5 wires, red, green/white, grey, orange and black/white, do you know witch voltage must arrive to each one with the car stopped and with the switch connector ON ?

Another reason that make it's doesn't runs ?

 

You can temporarily install a jumper wire between the orange and gray wire at the fuel pump relay connector. This should provide power to the pump. If the pump does not operate with this jumper wire installed, investigate the 12V supply at the orange wire and wiring to the pump from the gray wire.

 

Hello, I connected the orange with the gray with no contact key, and I heard a "clac" that I could not locate, but not a "zuuum". Then I turned the contact key and the electricity of the car was missing. I checked the fuses and they were all fine, so I turned the contact key ON and the electricity was OK again. And now with the ignition ON it does not sound nothing, and when want to start it still does not run. Can I give power directly to the pump connector under the car? What can it mean that the fuel level arrow is on top ( full )? Could it be that it does not have enough oil pressure? I just changed the torque converter for a repaired one. Thank you,

 

You can directly route power to the fuel pump to test it. If the pump does not run with power applied, the pump may have failed. My suspicion is that in the process of transmission removal and installation something was not correctly reconnected, such as a ground wire or connector.

 

Check the fuse beside the battery. As suggested above if you test suppling 12 volts to the pump at the rear bulkhead and the pump works it's wiring. If you supply 12 volts directly to the wire that goes to the fuel pump at the relay bypassing the relay then it's probably the relay, relay socket. If you hook up a test light to the trigger wire at the relay it should light for 1-2 seconds when you turn the key to run position. If it doesn't have 12v here then check the oil pressure switch. I've had them pull the voltage down so that the relay wasn't getting enough volts.

If the pump runs when wired directly but the car will not crank then could be an ecu issue, either the ecu itself or power supply to it.

Does the security light turn off after a few seconds? If not VATS could be going bad.