94 Blazer, W style. The problem is this: last week I did a big road trip and then came home no probs. Next morning the truck would not start, turns but no ignition. I noticed that the fuel pump was not running so I had it towed to the local garage where they replaced the 'defective' fuel pump, $630.
4 days later after visiting a friend the same problem happens- silent fuel pump, no start. towed again to same garage next morning. The mechanic starts it up right away and it starts all day long- no apparent problems! I told him that I cannot have this happening due to my line of work as a fishin guide so he puts in a jumper wire under the hood that is supposed to turn on the fuel pump in emergencies by bypassing all the other wiring, all you do is hook one end to the negative battery terminal. This sounds great to me.
Any ways, 2 days later at the end of a fishing trip the same problem happens-
silent fuel pump=no fuel pressure=no go. I think great, I'll just use the jump wire. It does nothing! silent fuel pump. It was towed again this afternoon back to the same garage.
Any ideas? I think it's a bad connection/wire somewhere.

 

check for voltage at the actual pump. then check the fuel relays on the firewall!!

 

thanks hillbilly, i gotta wait til monday. truck is at shop now and me at home.

 

mechanic tested and found 12 V at the harness near FP so he has ordered another FP and asked the sales rep to pay for the re install and part but rep is gonna be tough. Relay is good. They put new one in as tester and no change in problem.

 

my blazer is doing the same thing. i checked the plug got a really dim light with the tester. going to get another pump. any ideas. i put a new relay on it. chanded filter .friday i had 20 psi today none. can it be that my sending unit can be bad??????????????

 

I had the same problem, replaced the fuel pump, it worked for a short time and failed again. I took the pump out and tested it and it worked. I had a bad sendng unit, replaced that and it now works fine.