Good morning, all. Here's my issue. I have a 2003 Excursion (V10) 4x4, with 159,000 miles. Recently it will die while driving down the road. Complete loss of power and all of the dash lights come on. When you go to start it, it acts like it's out of fuel for a minute or so and then will start back up. It will run a few minutes and do the exact same thing. Starting from the cheapest part, I replaced the fuel filter two weeks ago. It was REALLY plugged! I drove it every day for the past two weeks and it ran great. This morning it started with the same symptoms again. My initial thought was the fuel pump, so I tested it this morning. It's running at 37psi with the key on and about 34psi while it's running. I left it hooked up for awhile and didn't notice it dropping at all. Sooooo..... what should be my next step? Will a bad fuel pump make it lose all power like that? I've read up on the regulator too. I like to do most of my own work, but I'm just looking for help on where to go next? Thanks in advance for your help!

ALSO..... I did have a Coil 3 misfire a few weeks ago. I chalked that up to the plugged fuel filter, but I went ahead and replaced that coil. A couple years ago I blew a plug out of the cylinder, but had a heli put in to fix it.

 

Your fuel pressure looks fine. Did you scan the current fault codes?

 

Yes, sir. It showed the cylinder 3 misfire as a "pending" code, but other than that, nothing. I'm at a loss. I just can't figure out the intermittent stuff. I've had fuel pumps go out before and they just quit.

 

I don't know if this applies to the gas engine versions, but for the 7.3l there is a common issue with the pickup screens in the tank being clogged. One way to find out seems to pull off the fuel line or return line and blow air back through the line to kick off some of the dirt in the screens.

 

His pressures aren't indicating that. Sounds more like a pump wiring/ground fault since it doesn't show up on the pressures until it just dies.

As for the cylinder misfire, one cylinder won't cause a v10 to die, run rough, yes...but not die.

How up on the regular maintenance are you OP? MAF cleaned, air filter fresh, COP boots and spark plugs recent etc?

A bad fuel pump can symptom like this, but you'd have to catch it failing on the gauge at the time it just dies. If you see the gauge at time of engine fail, you should still have pressure above 30 if the pump is ok....more like 35. This would mean running a gauge where you can see it and catching it in the act.

Check my other posts if you need a pump and can wait a few days, I found my original Bosch NOS on ebay of all places. Link in that post to the vendor etc.

 

Thank you, sir.

I'm pretty up on maintenance, except for the obvious fuel filter issue. Plugs and coils are all new within the past 12,000 miles. Air filter is maybe 3000 miles old. I haven't cleaned the MAF, but that's a thought. I've read up on the regulator being a potential problem, but also something about the relay.

 

Just another addition. The first time this happened, it died on my wife 4 times in less than 10 miles. Same symptoms as mentioned before. I drove to where she was, started it and it idled just fine. I decided to see how far I could go to get closer to home. I made it the last 15 miles without any issues at all.
This morning it went about 2 miles and died. Started up and went about 2 blocks and died again. It would run at an idle for about 2 minutes. Finally, it started and I drove it to work without any issues.

 

Based on this I think you're barking up the wrong tree. This description sounds to me like what would happen if you cycled the key off and back on. "All of the dash lights come on" is what happens when you first turn the key on.

I would look for an issue in the ignition switch. Sometimes they get loose or wear out. Importantly there's a different between the ignition cylinder, and the ignition switch. Either could be the problem.

Another cause that is down-stream of the ignition switch is the main power relay.

 

Thanks! I've been looking at that as a possible issue too. The only thing I keep going back to is how it sometimes acts like it's starved for fuel when I'm trying to start it back up. I just hooked up the fuel pressure tester and I'm going to drive it around for awhile and see if it drops at all.

 

Nothing wrong with checking fuel pressure.

Too much fuel and too little fuel behave the same way, it could also be too much.

Assuming you don't see fuel pressure suddenly drop, next time that happens before trying to start it again floor the gas pedal and then crank. If it fires back up faster then it's actually flooding out from being cut off suddenly while running at speed. Wide open throttle is how to quickly start a flooded engine, or extended cranking will clear itself more slowly.

 

Thank you. What would be a possible cause of too much fuel?

 

My guess on this one is it's an electrical problem turning the vehicle off, so you have injectors running much higher duty cycles than at idle when things are suddenly turned off.

Port injection sprays fuel mostly on the closed intake valve before it opens, especially when you're not just idling. At any moment you have several cylinders with fuel just sitting pooled on top of the intake valve, if you suddenly turn the power off the engine still spins a couple times around before stopping so those valves open and fuel gets in the cylinders but there's no spark event to ignite it without power.
To compound the problem cranking is something done "rich" where more fuel that normal is injected to get things going. Cranking however always assumes you're starting with a clear cylinder. If the cylinder is already loaded with fuel you can get too much in there and it won't fire. It was more common knowledge in the time of carburetors that an engine could be flooded, and the way to clear a flooded engine is to crank while the throttle is wide open. Fuel injected cars can still do the same flood clear with the throttle wide open, they have programming that says if the throttle is wide open don't actually fire the injectors while cranking.
If you've actually flooded the engine it will then often fire on just the fuel already in the cylinder. If you crank without flood clear, the flooded fuel will still usually expel out of the exhaust faster than new injections will replace it, so it will eventually get back to a combustible mixture but it'll crank longer to get there before it fires up.

So too little, or too much fuel, can cause that symptom where it is a longer time cranking before it starts. Given your description of the cutoff being immediate, plus the lights on the dash going on, my SWAG is you have an electrical issue with the ignition turning off as if the key is turned off and then back on. Running out of or low on fuel isn't an immediate off situation, the power will drop off over a couple seconds and then finally cough and die.

 

Thanks! I appreciate it. I'll read up on how to test to see if it has anything to do with the ignition system.

 

I'm swinging in the dark a bit here, but my wife's 2004 Expedition (4.6) had nearly identical symptoms. One of the symptoms was that when cycling the key, the instruments would get no power. After a few cycles, everything on the dash would peg, as if the electronics was doing a startup check.

I asked a mechanic friend about this and he blamed a module that was allegedly under the vehicle near the left rear wheel well. That module turned out to be the issue, but Ford put it some place else on the 2004s and I couldn't find it. The wife took it to another mechanic that found that the block where the module plugged in was heat damaged and the module wouldn't maintain good contact so both the module and block were replaced and we've had no more issues.

Your truck's issue and the Expedition's sound similar enough that I thought I'd share this. With both vehicles being 2004 Ford trucks there's bound to be a lot of commonality.

 

Your fuel pressure seems off.

At idle you should be around 28 to 30 psi.

18 in of hg vacuum is about 8.8 psi. So engine running and vacuum line disconnected or with key on and engine not running you should be about 37 to 39 psi.

Your difference is about 3 psi which is not right.
Check engine vacuum and fuel pressure regulator.