fuel (pump?) problem on GMC Sierra truck?

[greenmannowar]

I have a 2002 GMC Sierra 1500.
The truck had stopped, and it appeared to be the fuel sending unit
That unit is a canister containing the fule pump as well, and goes for about $400 retail.

To get the truck back on the road temporarily,
We changed the fuel pump (not the whole canister) and "hot wired" the fuel pump to a switched ignition 12v (fused) source.
The first time this was done, it worked fine for 1 week
(the pump burned out) .
We bought a new fuel pump and tried again.
This time, its working, but it takes 3-4 cranks before it starts.
It seems that the fuel pressure must be off, but we have no way to verify this.

1) What does the sending unit do ?

2) How many volts is the fuel pump?

(i checked the voltage at the sending unit and it was only 5 volts)


Any ideas for a solution ?
we changed the fuel filter, and have been driving it with the new pump, so there isnt any air in the lines
thanks though.,...

 

[Stargazer]

It's not the sending unit. All the sending unit does is control the fuel gauge. It looks like a toilet bowl ball...it measures the level of the fluid in the tank...same thing for the sender...it floats in the tank and measures the level of the fuel.

 

[bandit_60]

you say it works ok now but you have to crank it over before it starts ? did you bleed the air out of the lines and change the fuel filter ?

 

[bandit_60]

you say it works ok now but you have to crank it over before it starts ? did you bleed the air out of the lines and change the fuel filter ?

 

[bandit_60]

you say it works ok now but you have to crank it over before it starts ? did you bleed the air out of the lines and change the fuel filter ?