Over the past three weeks I've experienced random moments where my 5.4 won't start. I've tried to identify a trend (engine temp, outside temp, rain/dry) but it seems random.

My research led me to focusing on the fuel system first. I rented a fuel pressure gauge and kept it 3 days (Max I was allowed) and the truck never had a problem starting (figures). So naturally I always had pressure. The pressure was also in the acceptable ranges per the manual.

I've replaced the relay (figured it's a cheap fix to try). Still have intermittent no starts. I've noted when it doesn't fire I don't hear the pump prime. So I am thinking the pump is having moments where it's not running. If the pump doesn't prime I can turn the key off then back on until I hear it prime, then try the ignition and it fires. If not I keep flipping from off to on until I hear it run.

I've had the codes ran twice and all clear. I do not have a flashing Theft light indicating a problem with the PATS.

The truck runs great when it fires. It's just all or nothing.

So before I drop the tank and replace the pump does anyone have any advice on diagnostic steps to determine if the root issue might be something else? I don't want to replace a good pump unnecessarily. Or do all signs point to a pump trying to go out? Thanks

 

A bad crank position sensor or a dirty connector on the cps can cause that problem. I would also check the cam sensor.

 

Thanks. Any advice on how to test those?

 

I would first unplug and check for oil,dirt or debris inside the connection. Clean if dirty. A bad or unplugged crank position sensor the truck usually will not start. If I'm not mistaken same for cam position sensor. Start with cleaning connections first. Also both sensors are relatively cheap.

 

I am having the EXACT same issues also on a 2001 5.4. I did check the schrader valve on the fuel rails by pressing it down, right after the key was turned on and i got no fuel, and it would not start.

There should be pressure at the fuel rails as soon as the key is on right? I did check it again another time after the key had been on probably 30 secs and fuel did spray out and it started right after that.

There was also one time it barely started and it was idling really rough probably about 4-500 rpms, almost like it wasnt getting enough fuel. I killed it and restarted and it was fine after that.

The truck was sitting for a year or more when i got it in may and it probably had bad gas in it but I when ahead and ran the rest of it through... probably not the best idea.

The fuel pump was kind of noisy when I got the truck but it has since quieted down.

What are you guys thoughts?

I am planning on checking cam and crank sensors tomorrow but seems like a fuel issue to me.
-Thanks

edit: also replaced the fuel pump relay and it did not fix it. Also I replaced the fuel filter probably a month after I got it, it was REALLY nasty...

 

Mine started slow and got progressively worse. If you can determine it is a fuel issue and not fire then the pump is suspect since you've already changed relays and filter. I wasn't 100% but I knew it was 14 yrs old with 150k on it so having a new pump wasn't a bad thing. Also go ahead and spend the money on a good quality pump. Ford was closed when I got my so I couldn't go OEM. I ended up with a Delphi from Napa based on input from guys on this forum.

I replaced mine 2 days ago and it fixed my no start and idle problems. I was having surges when it was cold, my guess is a lack of consistent pressure.

If you change pumps watch videos of both dropping the tank and removing the bed. Dropping the tank can be a PITA... Not much room to work. If I have to work on it again I may try taking the bumper off and sliding the bed back. I can't say if it would be easier as I haven't done it yet.

Also you can't siphon gas from most of these trucks so keep that in mind if you're still driving and fueling up. I tried to keep mine around 1/4 until I got to fix it. However if you move the bed instead of dropping the tank that won't matter.

Good luck.

 

Yep same here. Didn't start one time and it just got worse after a while.

I'll probably try to take the bed off when I do it because my dad has a tractor I can borrow to help lift it off.

I'm gonna do some more testing today but sounds like ill most likely end up replacing the pump. Ill probably go with the Delphi as well if I cant find the Motorcraft.

Do you know if there should be pressure at the fuel rails as soon as the key as on? Or is it after you start cranking? I would think it should have pressure as soon as the key is on.

 

should be there after you turn the key on when the pump primes. Be careful lifting the bed. Don't just wrap straps under it and pick up you can dent the fenders.

 

Also another poster pointed out on the supercrew the pump is under the back seat. Check that before you pull the bed, you may have to drop the tank regardless.

 

Alright I'll check that out first, thanks for the advice.