Fuel Pump problem

[rjordan5749]

Well I had dropped my tank to replace the sending unit and reuse the pump. Had to go out of town for 4 months so didnt get around to putting it back in the tank for about 6 months. Installed it all today and u can hear the pump turn on but no fuel being pumped. Not even before the filter. Everything in the tank was replaced but pump. Could the pump be bad even though you can hear it turn on?

 

[dyeager535]

Were all the lines hooked up, and the sender mounted in the tank?

My first thought is you left a line/lines open, and a mud dauber got in there and plugged the outlet.

 

[rjordan5749]

Yea All the lines are hooked up i did leave the lines open. So i guess ill drop the tank again. and check to see if clogged. Can the pump come on and not pump?

 

[dyeager535]

I'm sure they can, don't hear of that being a problem that I can remember, but it could still be the pump I suppose.

Before you go further...you know that the pump only runs for a few seconds unless the engine is cranking or running, right? Just didn't hear how you tested it. You need to put 12V to the red wire hanging off the fuel pump relay connector to force the pump to run continously. Only thing I'm getting at here is that if there is no residual pressure from the pump after the two second prime, it could be losing pressure quickly.

 

[Thunder]

Yes. The pump can run and not pump. If you are going to drop the tank i sure would install a new pump. Buy a good one from GM or a Walbro pump.
Also
Check the small hose between the pump and sender outlet many times they crack with age and leak bad.
New pumps come with a new hose for this reason.

 

[dyeager535]

x2 on that hose. Numerous times here I've seen that be a problem. You'll see it if that's it!

 

[rjordan5749]

Well to check it i had put 5 gallons in a bone dry 31 gall tank. Turned it on and off a few times. Then Cranked for a few min and tryed that several times. Fuels not making it to filter. But pump it turning on for 2 secs and while cranking. When replaced sending unit i replaced everything but pump that includes that little black tube and clips that hold it on. Is 4-5 gallons in tank enough?

 

[trikstark5]

You didn't switch the wiring around did you? If the wires are backwards, the pump will acutally run backwards therefore no fuel.

 

[rjordan5749]

I dont think so but anything is posible at this point. i cant remember if the wires can clip on one way or u could put them on backwards. I guess need to check that.

 

[dyeager535]

Sending unit wiring harness on TBI is a keyed connector. No way to do it wrong unless the wires were cut.

4-5 gallons should be plenty on relatively flat ground.

It should only take a split second to get fuel from the tank to wherever you have the line open...no minutes of cranking, just wears the starter and battery down unnecessarily.