Need help with fuel system!!

[amikk97]

Hello guys,
Im new here, and this is my first post. I have a 1987 GMC Sierra R1500. I just replaced the gas tank because of a nickel sized hole in the side of the tank. I ordered a new one and hooked up the straps and put in the fuel sending unit, plugged in the lines and electrical stuff, filled her up with 5 gallons and now she wont start she just cranks and cranks but wont turn over. the wiring seems alright because the fuel gauge is working, but it seems that the pump is not working. i read on other sites that priming the pump by turning the key to the on position will help and you should be able to hear the pump whirring or buzzing, but all i hear is a click after about 3 seconds. i know its probably the fuel pump, but i wanna see if it could be anything else because i am really NOT looking forwards to taking the tank down again. any ideas? please help.

[Stepper86]

Did you re-used all the original stuff, and just replaced the fuel tank? And the truck was running and driving before you took it apart?
Go back and check that you re-connected everything, old dirty connectors can sometimes look like they go in, but might not be seated fully.
The pump should switch on when you turn on the ignition, it will run until fuel lines are pressurised. You don´t need to crank the engine for this.
Check fuses, maybe something shorted out while you were working on it.

[Just call me Sean]

Did you hook the pump ground back up?

[Dead Parrot]

To verify the no start is due to no fuel, dribble a few drops, don't need much, into the intake and try to start. If if fires, even just a little, you have a no fuel problem. If it doesn't, you likely have other issues that happened at the same time you changed the tank or maybe because of it. It sometimes doesn't take much wire wiggling to blow a fuse with old wiring. Or knock a connector loose.

[amikk97]

i checked all fuses all are fine. ill take a closer look at the lines tomorrow. the truck was running and driving fine before I replaced the gas tank

[amikk97]

and yes the ground is hooked up, but not to good. could that be the reason it isn't pumping

[pontgta]

Can you hear the pump? If you can hear it there is good ground, but make sure everything is tight. Make sure you hooked up the lines corrrectly(yes i did make this mistake one). Vent to vent return to return and fuel to fuel filter.

[cadillac_al]

Originally Posted by pontgta

Can you hear the pump? If you can hear it there is good ground, but make sure everything is tight. Make sure you hooked up the lines corrrectly(yes i did make this mistake one). Vent to vent return to return and fuel to fuel filter.

My buddy has an 87 and somehow he got his fuel lines hooked up backwards too. I didn't lay under there to look at it but that is hard to do on the older trucks because the lines are different sizes. Are the lines on the 87 the same size?

[amikk97]

Im pretty sure the lines are correct, but they are different sizes. im gonna take a closer look tomorrow afterschool and make sure all the wires are hooked in right.

[amikk97]

Now that i am looking more into this i am starting to think it could be the relay. does anyone know where this is located on an 87 sierra? could this be why it is not starting?

[amikk97]

I should also mention while i was waiting for the new tank to come in i had disconected the tank and FSU from the truck, and my idiot friend tried starting it. nothing was hooked up to the lines. could this have done somthing?

[Just call me Sean]

Originally Posted by amikk97

I should also mention while i was waiting for the new tank to come in i had disconected the tank and FSU from the truck, and my idiot friend tried starting it. nothing was hooked up to the lines. could this have done somthing?

No.

Relay should be on the firewall. It has a red wire hanging from it that you can put battery positive to and hotwire the pump.

[amikk97]

Thanks Sean, ill take a look when i get home from school

[amikk97]

well good news guys it started up! it took about 3 tried but on the 3rd it sputtered to life. must of been the cold weather as it is mid 60's today. now I just gotta get these sqeaky belts fixed.