Hey All,

I'm currently in the midst of changing my fuel pump on my 2001 Ranger with a 2.5L. I'm not seeing any pressure at the fuel rail (confirmed with a pressure gauge). I pulled the pump and did a quick test hooking it directly up to 12V and heard it make a little noise, but no clue if it's how it should sound. The somewhat concerning issue is when I test the voltage, I'm only seeing 5.5V with the key on. Is this normal? I'd hate to replace to pump if it's not that at all.

Another piece that's a bit concerning is that the 20A fuse for the fuel pump that's under the hood never sees any voltage when the key is on.

Just a quick backstory on when the truck stopped running... I accidentally killed the engine in traffic yesterday and was very low on fuel. I then tried to restart and it wouldn't. I put 2 gallons in but still no go. I tried starter fluid and got it running, but it would die immediately after stopping spraying.

I'd be glad to give any more info if need be, and really appreciate any help you all have.

Thanks!

James

 

Welcome to FTE.

I'll see if I can get things started & maybe others will chime in.
Good input on how the problem began & checking pump & fuse voltage & fuel pressure with a gauge.

Seeing as how our fuel pump power relay is often a problem part, try swapping it out with a known good like one not needed to run the engine, like the A/C power relay & see if the pump will wake up & run for a couple of seconds & shut off at KOEO & let us know how it goes.

 

Good call on swapping the relay. Unfortunately, I already swapped it for a known working one with no luck.

 

OK, good feedback on trying the fuel pump power relay swap. SO, lets think about this some more. If the fuse you say doesn't have power to it is the under hood 20 amp fuel pump fuse I think #23, its supposed to have B+ power to it at all times. So if power isn't there, then the fuel pump won't run to prime the system for a start.
So make sure you have B+ on both sides of the fuse at all times..

 

Yeah, it's the 20A fuse in the block under the hood with the other fuses and relays. When I checked it for power, I pulled it and checked the voltage across the two terminals. Should I be checking it to ground instead?

Can you explain what you mean by B+ power?

 

Yup, you should be checking B+(Battery +) to a good clean, un rusted, non corroded or unpainted ground, bolt, stud, bare metal surface on the body or engine, in order to get a good eletrical connection & know if the fuse & its B+ feed are good. With the fuse removed, only one of its connections is hot/with B+ voltage all the time. If the fuse is in place & its good/not blown/open circuit, you'll read B+ to ground on both sides of the fuse.

If you have B+ to & through the fuse, go inside the cab, passenger side footwell on the firewall just above the carpet line, find the fuel pump inertia cutoff switch & make sure its not tripped/little red post atop it sticking up, if it is, push down to reset it & back probe both of its electrical connections to make sure B+ is there for a couple of seconds at KOEO. This will confirm battery voltage is making it that far, which is most of the way to the fuel pump tank electrical connector. If you already have access to the fuel pump electrical connector, just cut to the chase & back probe the B+ lead to ground there, to see if battery voltage is making it that far without voltage drop.

If KOEO B+ is low at the tank connector then measure it at the output lead on the inertia switch & if low there, try thumping the inertia switch to trip it, then reset it to see if a new position makes it right. If resetting puts the fix on it, replace the inertia switch, as its internal contacts are likely corroded. There have been reports of faulty inertia switches.

If all looks ok electrically, maybe look to a clogged fuel filter from running it low on fuel. More thoughts for consideration, let us know what you find.