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fuel issue.

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xsmokey11499x

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hi all. my problem is with my 87 k5, Tbi. 350,700r,208 .
I went to start my truck . and it just cranked and cranked. I poured a little gas in the TBI. the truck fired then died. I pull out the sending unit. to make sure my fuel pump didnt fall off . ( its happened before) it was still connected, I looked at the wires from the sending unit, and the plug was melted a bit, so I snipped the plug off, and bypassed it. Still nothing. I have had No signs of fuel pump failure etc. How can I test the fuel pump ? or what else could be the problem? Fuses are good
 
Did you clean and reconnect the ground to the frame? This step may have been missed if the tank is hanging down under the truck.

Are you getting power to the pump?

You can get all the power in the world to that pump and it will do nothing if that ground is not connected.
 
496truck said:
Did you clean and reconnect the ground to the frame? This step may have been missed if the tank is hanging down under the truck.

Are you getting power to the pump?

You can get all the power in the world to that pump and it will do nothing if that ground is not connected.
Click to expand...


sorry should have said I have an "access panel" cut out from the PO. in the bed. just above the sending unit so no dropping the tank.
 
Gotcha. Still check the condition of the ground. It's common for the wire to break off or just be corroded to all hell. That will stop a fuel pump in it's tracks.

The burned connector is a clue. Something pulled some amps through there. Could be that the pump is shorted. Did you check for power?
 
Agree, check for power and ground at the pump. Realize that the pump won't have 12V after the ~2 second prime, unless the key is cranked. Or, you run 12V to the single red wire just hanging off the relay going to nothing.
 
It's a ground wire that goes from the sending unit over to the top of the drivers side frame rail. Everything in the tank grounds through it. IE: the pump and the level sender.
 
yeah the ground is good, I unhooked it to see what happens, and my fuel gauge tacks out Past full. I hooked up a wire from the battery, to the red wire on the fuel pump relay, still nothing. Fuel pump isnt kicking on.. maybe it just gave out.
but it was running 100% yesterday.
 
They can die, just like that. Couple weeks ago I drove my daughter to gymnastics, shut the car off (my wagon not the K5), walk her in, come back out and the car just cranked away. Nothing. Main fuel pump (the car has 2, low pressure in tank and main under car) just up and died.
 
496truck said:
They can die, just like that. Couple weeks ago I drove my daughter to gymnastics, shut the car off (my wagon not the K5), walk her in, come back out and the car just cranked away. Nothing. Main fuel pump (the car has 2, low pressure in tank and main under car) just up and died.
Click to expand...

im going to pick up a tester. and see if Im getting power to the pump.

is there a way to physically test the pump? IE pull it out of the vehicle and test it
 
Yeah, connect it to power and ground. It'll make the pump spin but wont get you any pressures.
 
I have another test for any one reading this. Have someone crank the truck while you hit the center of fuel tank right where fuel pump is! Have to do this in first 2 seconds while priming or when cranking. Has worked a couple times for me and good diagnosis of elelctrical connections or electric motor in pump going bad.

2 good pumps I know of are AC/Delco and Carter. Carter is a better pump but is noisier. Some other cheapies just don't last.
 
alright well heres another problem, didnt want to create another thread since It's still fuel related..
I put the new pump in yada yada yada. now when I go WOT. or even 1/2 throttle my truck is bogging down.

would that be.. the filter?
 
alright well i got the hesitation or whatever figured out. my sending unit also went out. ( gas gauge quit working)

I put a BRAND NEW sending unit in, put the fuel pump in etc. wired it all up
but now when im a Little low on gas say 1/8 of a tank. and i make a turn. my truck acts like it's running out of gas. and sometimes shuts off!
 
I have heard of that in tank hose on the pump going bad. If it cracked, it could create those symptoms. Did the new pump come with one? If you buy one, it MUST be submersible. Make sure you specify that.
 
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