Been a long time since I've posted on here.

So my 2005 6.0 is broken down. Died on the highway last night at 30 miles per hour, I was accelerating after coming out of some light traffic. Coasted to the shoulder of the exit ramp. Attempted to restart the truck, wouldn't restart. Similar symptoms to when I had to replace my dummy pipes last year. Got the truck towed to the house. Truck started fine this morning, so I was able to park it the way I wanted it in my driveway and get it prepped for the teardown.

No CEL, no pending codes. I'm thinking, based on the fact that the truck started fine this morning that the issue is a high pressure oil issue, just like before, but that most likely I should be looking maybe at the HPOP STC fittings. Any thoughts? My truck is a 2005, and I'm seeing that there is a difference between STC fitting kits for early 6.0 engines and later model 6.0s. Did the Excursions follow the engine updates? Or did they get screwed with the engine update the same way they did with the front suspension update?

If this is an HPOP STC issue, as I suspect, how difficult is this? I'm expecting maybe a day to tear down, day to build up kind of thing? Good time to do the EGR cooler and oil cooler, while I'm in there.

 

Another 6.NO break down, sigh, feel for ya, and glad i got the V10.

If it shut down i would suspect fuel supply.

 

Definitely fuel supply related, but based on the fact that it waits until the engine is hot to die, then restarts when cold, I'm thinking that it's related to the HEUI system. Since the 6.0 injectors are fired off by high pressure oil, driven by the high pressure oil pump, here is my logic: Oil viscosity reduces when it gets hot, allowing oil to bypass through leaks in the system. Once the leak has been "sprung" by the hot oil, the truck cannot be restarted until the oil system cools and oil viscosity returns to its normal thickness.

 

i see the logic, and it is possible, but if the leak is big enough to cause that big of a problem, i would not expect the viscosity change to be enough to control that all by itself, it should be barely running as it is with that kind of a leak, and then when the oil gets hot, shutting down, it wouldn't be running normal when cold if the leak was that severe. i would be shocked if that's all the issue is.

I would more likely attribute it to a fuel pump, and here is my logic from that, based on having it happen to me several times now.

Fuel pumps are not an on or off component, they vary in output greatly, even if they are not variable output pumps, worn out pumps usually tend to get weaker and weaker, and the problem is easier to track down, however 3 times now in my case, i have had pumps that would shut down if they got too hot. Take this example.

1. Vehicle starts up fine, no apparent power loss, drives good, but then on the road 30-45 minutes or more into the drive, suddenly stumbles a bit, and a few seconds later stalls completely and refuses to restart.
2. Vehicle is towed home and parked for an hour or two, or overnight, and fires right up, no problems can be found, even a 10 minute test drive comes out perfect.
3. Problem repeats again next time you go on a long drive.

I forget on the 6.NOs but is the pump in the tank or external. For in tank pumps, i discovered a quick temporary fix was to fill the tank, the fuel level gets over the pump and cools it down and it becomes operable again until the fuel level falls too low to keep it submerged and thus cooled. But eventually the pump usually fails within a month or two of this being the problem.

If you can get it to shut down again, spray something over the pump to cool it and see if the engine fires back up, if it is external of course i mean, i think the 6.0 was external if i recall.

 

Wow, that's a really good point. Thanks.

Interesting theory. The fuel pump is internal, and cooled by the fuel.

As a troubleshooting measure, filling the tank completely could be a way to test the hypothesis. I'm down to test it.

 

i just looked your pump up on rock auto and it does not look like mine, with the fuel hat on it and all, like an in tank pump.... Maybe i looked up the wrong one, but this one almost looks like it might go on the motor.

 

This would be better to be posted in the 6.0 area since it's common to trucks and the Excursion. Much more audience...

 

I got it wrong. For some reason I thought there was a primary fuel pump in the tank and a secondary boost pump on the frame rail. The one you found is the fuel pump, and you're correct, it's located on the frame rail, approximately under the driver's side door. Also doubles as the fuel filter housing.

 

Well that sounds like an easier fix than dropping the tank, if it is the pump.

 

Years ago I had a mustang that would act like this. It would start cold and run fine for 15-20 minutes and then choke out and die. If I let it sit for 30 minutes I could get a few more minutes of driving before it died again.
After chasing suspected problems I figured out it was a clogged fuel filter. Is it was running the gunk in the tank would obstruct the filter. As it sat for a while some of the debris would settle to the bottom of the filter and let enough fuel to pass to run properly for a while before obstructing the flow again.

It might be worth checking the fuel filter.

 

Good suggestion, my filters are new though. I just changed them a couple of weeks ago when I did my oil change. Not a ton of debris in my pump housing filter or my secondary filter.

 

Agreed. I'll have to take a look at the fuel pressure. Anyone have guidance on how to measure fuel pressure at the rail?

 

Update: Just purchased Forscan Lite app and a bluetooth device to sync to my phone, so I'll be able to do some troubleshooting. Hopefully I'll get answers.

 

Measure fuel pressure at the secondary filter housing with a sending unit and gauge. I won’t run mine without being able to monitor fue pressure.

 

White & Blue MaxTow Double Vision 100 PSI Fuel Pressure Gauge

So something along the lines of that setup?