Lost Fuel Pressure

[custodian]

I was driving my 86 Dually home after putting some gas in the drivers side tank and it just cut off. Had my wife come and pull it home. I poured some gas in the carb and it run. I removed the fuel inlet at the carb, no pressure, and put an empty clear bottle on the end of the line and turned the motor over and no gas. I have dual tanks and was running on the drivers tank. I'm thinking it's just the fuel pump.

Now my question: If the tank switch goes bad would that block the fuel to the fuel pump? The tank switch had been working before. It will not crank in either the passenger side tank or the drivers side tank.

 

[nvrenuf]

Does that truck have a mechanical pump on the engine? I’d see if there’s fuel at the inlet side.

 

[custodian]

Does that truck have a mechanical pump on the engine? I’d see if there’s fuel at the inlet side.

Yes, mechanical pump on the motor, 454, and no fuel when I removed the inlet line to the pump.

 

[Broken85]

If you get under the truck and have someone throw the switch, you should hear the valve move. If you hear it working, I’d start looking at the fuel pump

 

[Ricko1966]

I'd put a hose on the inlet side if the pump, then drop that hose in a mower can full of gas. If the problem is gone.If not repeat your pressure side hose in a bottle test again. Still no gas,I'd pull the pump and bench test it. If you get gas out of the mower can start checking for broken hoses etc. on the suction side of the pump. The pump will pickup air before it will pickup fuel if there is a hole in a feed line or hose. You can also plumb around the valve with rubber fuel hose for testing.