Weird issue, I'm sure.

I have a 2000 Excursion with the 5.4L V8.
I've read several threads about intermittent starting issues like the PATS and so forth, so I'm up to date on that. My truck hasn't acted up since I read them.
I'll check those issues when it does, but what I've noticed is that it only seems to do act up when the fuel is low... as in like with the fuel light on.
It's not out of gas.

The motor will crank over good and strong, but not start. I can wait a few minutes and it will start.
When this first happened, I thought that I had luckily run out of gas at the pump. I'd pulled up, turned it off, and then went to restart it to pull to a different pump but it wouldn't start. I fueled up and it started.
I didn't see anything about it only doing this when the fuel was low on the threads I've read about the PATS, IFSS, Relays or any of those.
***ALSO**
When it doesn't start, excuse my lack of technical terms, there is something under the hood along the driver side firewall that looks like some sort of emmission control part that makes a roaring noise.
What is that? I've never noticed this before. Could that also be related.
I know this makes me sound very un-mechanical, but the truth is that I'm fairly experienced... just not on this issue.
I thought I'd run out of gas, but it did it again today.

 

Our fuel pumps are cooled via the fuel in tank.

Running the fuel so low that your fuel light comes on is killing your pump. I suspect your pump is on its way out now.

I personally never let fuel guage get below 1/4 tank.

Your issue was probably due to fuel pump over heat due to lack of fuel to cool unit.

PLUS once fuel pump power wires are not submerged in fuel things get dangerous really fast due to access to oxygen in air in tank. That's an explosive combination. Don't let fuel level get that low.

 

Would being low keep it from cranking even when it hasn't been running, like first thing in the morning after it has been sitting all night?

 

Cranking or starting?

Motor will crank and not start if PAS is triggered with say a bad key.

If it's not even cranking than you have a starter circuit issue.

 

It spins over nice and strong, it just doesn't start.
It did this about a week ago when I stopped to get gas. The fuel light was on.
Then, fine all week. This afternoon when I went to leave it had been sitting since Friday night and it did it again. After about 5 minutes, it started.
It did fine around town this afternoon, but I got home, turned it off and immediately needed to crank it back up again and it did it again.
After about 5 minutes again, it cranked.

Fuel is low now, too. I didn't put those two things together until about an hour ago.

 

Hi Dane,

I'm also in the camp that thinks you've got a fuel pump on the way out.

Like all parts, they have a finite life span but you can extend that simply by keeping enough fuel in the tank to cool the pump. Depending on the vehicle, the tank is about a foot tall. When the tank is 1/4 full there are 3" of fuel left in the tank. The pump is already partly exposed. When the "Low Fuel" light comes on you might have as little as 3/4" of fuel in the tank. Since the pump is 4"-5" tall, most of it is exposed to the air in the tank and can cool only from the cooling of that part of the pump that is still submerged. The exposed part includes the motor, which is where the heat is generated. Keeping the pump submerged keeps it a few degrees cooler and extends its life.

If you're not comfortable swapping out the pump, start shopping around now for somebody that can do it, and will do it within your budget. I was out of town 3 weeks ago when the pump in my wife's Expedition went out. She couldn't reach me so she called a tow truck and got it to a mechanic that she knew. $1,000 later she had her car back. That was highway robbery. Two months ago the fuel pump in my Excursion went out at work. I called a mechanic friend and we swapped it out in the parking lot. $350 for the pump and $100 for him, $450. If you're familiar with the process the pump changes in about an hour. (And is a LOT easier with the tank nearly empty!)

 

Thank you. I'm pretty mechanically competent. I've swapped them in parking lots, too, but I've just never heard that keeping it submerged will extend its life or that running it empty too much can damage it. For the last 2 or 3 months I've been running it really low, so that all makes sense,

Tanks again! (Pun Intended.)

 

I suspect that's the fuel pickup foot, not the pump. When the foot inevitably breaks, it brings the fuel pickup ~2" from the bottom of the tank AND reduces it from a 3" wide pickup to 1/4". The pickup is $30 from Ford. I've found a broken foot on every pump I've pulled.

 

On gassers? There really isn't a pickup foot on our fuel pumps, this is mine, it's sitting sideways, the end opposite the wires is the bottom that snaps into the base which is permanent in the tank bottom.

Attachment 282646

 

Sorry, I skipped some context and assumed it was diesel.

 

I wish! The only complaint I have for my Ex.

 

Thanks for everyone's response. I've kept it gasses above 1/4 tank since I forts posts this a week ago and t hasn't given me any trouble. I plan on replacing the pump this week so that it doesn't give up the ghost at the most inopportune time like on the interstate in the rain at 21 degrees and windy.

 

What is the fuel pressure reading at the test port when it doesn't start?