2001 5.0 no start

[Ford94sho]

Towed a trailer with a big zero turn home Thursday, fuel did get pretty low on the 25 mile trip, but was running fine. Came of Friday morning and would crank over fine, wouldn’t start. After holding the throttle wide open it finally started and I moved it for the weekend. Added 3-4 gallons of fuel yesterday, still wouldn’t start. Nothing from the shrader valve under the hood. Did finally get it to start again last night with lots of throttle pumping and holding wide open? No CEL light, no codes in the system. Did unplug the TPS and it acts like it wants to start but won’t. Plugged it back in, right back to cranking over zero start. I know it does have a Napa fuel pump that’s 2.5-3 years old. Like I’m pretty stumped, kinda feels like a TPS issue Vs Fuel Pump

 

[J_C]

If you are getting no fuel out the fuel rail shrader valve once the key is in the on/run position (without even trying to start it) the pump is acting up. I'd get a pressure tester to confirm this if it were under pressure, but with nothing, has to be the pump.

I mean there are some less likely things that could cause the pump to be intermittent, like a dodgy fuel pump relay, or inertia shut-off switch, or corroded pump connector, frayed wiring, but ultimately the question is whether 12V is getting to the pump when you're not getting sufficient if any fuel pressure, then if you are, pump is at fault. If you aren't, backtrack towards where 12V stops. Wiring diagram attached.

 

[8TZX]

Turn the key to the run position without turning it to the start position. Listen for the fuel pump. You should hear it running with a consistent tone. If not, probable fuel pump issue.

 

[crunchie_frog]

fuel pump, running tank low on an old, old fuel pump is a sure fire way to kill it.

 

[Mbrooks420]

fuel pump, running tank low on an old, old fuel pump is a sure fire way to kill it.

This is a myth. I run my fuel tank to the light every single time and get the typical 150k+ lifespan out of the pumps. They don’t run hot enough to need special cooling. If so they’d make a pretty poor choice to run in a flammable liquid.

 

[crunchie_frog]

This is a myth. I run my fuel tank to the light every single time and get the typical 150k+ lifespan out of the pumps. They don’t run hot enough to need special cooling. If so they’d make a pretty poor choice to run in a flammable liquid.

you may very well be correct. I am basing it on having to replace two fuel pumps in my daughter's car, both time failure happened after tank ran very near empty.

 

[J_C]

I'd guess low quality or factory defect pump that does run hotter than it should and the low fuel just exacerbated that, accelerated its demise... IF it is the pump itself. On a newer vehicle that is most likely but after two decades, could be anything from road debris hitting a wire, rodent chewing on it, rubbing from vibration causing an intermittent short... Telltale sign is whether voltage is getting to pump when it should be running and if staying fairly high near 12V.

 

[RoyKelly2]

you may very well be correct. I am basing it on having to replace two fuel pumps in my daughter's car, both time failure happened after tank ran very near empty.

2.5 - 5 years old is not an old pump. I usually get10 years or so on a pump, unless there is crud in the tank that gets sucked up when the tank is nearly empty, but there are bad pumps out there

 

[Mbrooks420]

Or, it was just the pumps natural end of life, and had nothing to do with the level.

 

[Mbrooks420]

With the cheapo pumps (airtex, wells) you can expect them to fail in a year or two, if you’re lucky.

 

[Ford94sho]

Thanks for everyone’s input. Def looks like I’ll have to do some wire chasing, shot some starting fluid in the throttle body and she fired right up. Ram it for about 45 mins & shut it down, wouldn’t restart

 

[Mbrooks420]

Sounds like a fuel pump, not wiring.

 

[RoyKelly2]

Sounds like a fuel pump, not wiring.

Agree... or start the wiring check at the pump. If you have voltage there when you should it's the pump

 

[christopherjost]

Agree... or start the wiring check at the pump. If you have voltage there when you should it's the pump

Got 20 years on my first pump but I also fill at 1/4 remaining. Pump is cooled by gasoline and if you were pulling a load, the pump was running hard. And it’s June. And you probably didn’t want to stop often for fuel.