What am I missing?

[Stepside Billy]

Trying to get my 1987 G.M.C. running. I went to start it, she fired up and died 15 seconds later. When I went to start again I didn't hear the fuel pump like I usually do. I replaced the fuel pump and relay but still don't hear the pump and she still won't start. I checked the fuse in the fuse box in the cab but it was good. She will start when I pour a little gas in the TBI. What else can I check? I don't mind changing parts out because I have no idea how old they are. I have to get her running for work. Thanks! Oh, 5.7, auto, V1500.

 

[yevgenievich]

Does the pump run when key turned on for few seconds? Will the pump run if the relay is jumped across?

 

[Stepside Billy]

No, I don't hear the pump. It's a new relay.

 

[yevgenievich]

on the relay, check the orange wire, it should have 12 volts on it with ignition in the on position. Next there is a red wire that would not be going anywhere. If you apply 12 V from the battery to that wire, the fuel pump should run. If the red wire is not there then other way is to apply 12 volts directly to the tan/white(or gray) wire. If pump is not working after applying power here, next step is to go to the pump and test it there and check for loose ground as well.

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[Stepside Billy]

Ok, I'll try that. On doing some research, my truck had dual gas tanks but a p.o. Pulled the passenger side tank out. I read about the tank switch possibly causing problems. The truck had been running fine but right before my problem the check engine light came on throwing code 24. Again, thanks for the help!

 

[yevgenievich]

Ok, I'll try that. On doing some research, my truck had dual gas tanks but a p.o. Pulled the passenger side tank out. I read about the tank switch possibly causing problems. The truck had been running fine but right before my problem the check engine light came on throwing code 24. Again, thanks for the help!

selector switch could cause problems too, but if the pump is not running at all, then that would be the first thing to figure out.
Code 24 shows speed sensor fault. It might either because there are problems with 12V source in the wiring or might be completely unrelated issue

 

[Stepside Billy]

Well I got her to run but it's leaking around the seal! Out comes the tank again!! #%^*€£¥!!

 

[Stepside Billy]

Pulled the tank and reset the seal. Tested it BEFORE I bolted the gas tank up!