I know this has been discussed on many forums and many threads, sorry for more of the same. Currently, own a 2015 F350 6.7 with just over a 100,000 miles. This is, or was, the best truck I have ever owned, even over a 7.3, well except for DEF.
The problem started about a month ago, the low pressure fuel warning popped up and about a mile later it went into limp mode. My wife was driving and alone, not a happy lady. We got it back to our RV park in Yuma AZ and I changed the fuel filters. I am over the top careful about changing them every 8K and even had a Ford Dealership install new ones back in October along with most every fluid in the truck. This made it all better for a few days and then it happened again, yep she was driving alone. This time I took it to the local dealer, they could not find anything wrong and cleared the codes. They did say the tightened up the lower filter housing. I told them I had it up against the stops and hoped they did not go to far. The next day same thing. So I order a low pressure pump from Amazon (OEM) and installed myself, this lasted about a week and again shows same error messages. Only this time we had to get towed to the dealer. They dropped the tank and checked the fuel lines and draw tube, all good. I asked about my install of pump and the condition of the HPFP and they said all was fine. Not sure they actually checked the HPFP. They put on a new fuel cap. This was a very expensive cap. I had told them that during one of the episodes I loosened the cap thinking it could be a vacuum, it was not. Well it has been about 350 miles and guess what happened to my wife the other day on the way to the store. It did not throw a code or show an error, but the low pressure pump was humming, noticeable at idle but not loud enough to hear at highway speed. Since then it has been off and on. If we were home, it would be an inconvenience, but we are 6 weeks from starting a 3000 mile trip home with a 14K fifth wheel on the truck. Sorry for the long post, but I am getting worried. Wife says dump it, but I really like this truck and it is not like the dealerships are loaded with new ones. Any advice would be appreciated. Mr Polarlys has been kind enough to offer good advice already.
Regardless of the outcome I will keep everyone posted to the outcome, good or bad. Who knows I may have a large amount of time while sitting along the road in West TX waiting on a tow truck.

Thanks in advance

 

If you want to keep it and since it's not throwing any codes, I'd suggesting getting a device that lets you monitor the truck a little better so you can at least figure out what's happening. Right now, it's all just a shot in the dark.

 

You may want to have another dealer look at it. Also there's a pressure sensor that monitors the low pressure fuel pump pressure so maybe need to look into that sensor.

Also you need to confirm your low pressure fuel pump is actually a Motorcraft product since there's a lot of counterfeits parts out there.

 

My vote is that when the dealer dropped the tank, they didn't actually examine the tank itself, just the pickup. If you have used fuel additives in the past, the little round cardboards from inside the cap can drop into the tank. Those cardboards are about exactly the size of the fuel intake, and slosh around in there blocking sometimes, and not later.

Have the dealer drop the tank again, if you have been using additives. If you never have, then nevermind...

 

All good replies, thanks. What monitor would you suggest? The pump was genuine Ford, as were all the filters I have bought over the years. They texted me a pic of the tank on the shop floor with the inspection cover open or what ever is the big hole on the top. Said it was good, I even asked them if the tube was cracked, they said no. I did speak with a mechanic that is from WI, this guy is very good. He said that since I have gone through the tank, filters and pump the only thing left is the HPFP. So when I get to the dealer on Wednesday I will have them pull the high pressure regulator and check for metal. Really hope he is wrong, but who knows.

Thanks again for the advice and help
Carl

 

So here is the update. The service writer at Ford said he would not pull the regulator and that it was up to the tech. He actually got huffy with me. I said I would pay for the inspection just for peace of mind and if it was OK, go ahead and change the filters and I :will be on my way. My appointment was for 7:30, he insisted it was all up to the tech, he then went on to tell me that it might be a day of two before i heard anything. I waited until 8 and noticed that the truck was still where I parked it, at which time I went and told them to forget it and left. Why would you make an appointment and just sit in the Que until they get to you, I thought the whole idea of an appointment was so you would not have to wait so long. So I guess if I asked for an oil change or new shocks it would be up to the tech. I called Ford service then told me that the dealers are independently owned and that I should try another. I may stay with Ford, but it is getting to be struggle. sorry for the rant. I may not follow up for awhile, I guess I am not really feeling like a Ford Truck Enthusiast. LOL

 

Unfortunately, Ford service departments vary greatly in how they operate. I had a similar experience with one for an alignment, had an appointment, waited 45 minutes and the truck was still in the parking lot. Told them to give me my keys and I was on my way. Some are much better and are actually respectful of your time but that does seem to be less common.

 

I have given up on waiting for the truck to be worked. Nothing more frustrating that sitting in the waiting room and nothing going on. When I make my appt's the dealers I routinely deal with have loaners, so make that the request first. that usually means my appointment is booked further out since loaners are in high demand.

Nowadays, I do work from home, so I drive a lot less than i used to as well. So quite often the wife and I will drop the vehicle off the night before, and pick it whenever it is done.

 

As promised, here is the latest info. Truck has about 800 miles since dealer pulled tank and cleaned and checked all fuel lines. This AM I heard the dreaded whine from the lift pump on the frame. After a couple of miles the low fuel pressure/ reduced power warning came on, we stopped in a parking lot. While we were sitting I added additional ford 22 fuel conditioner, drained the water separator, no vacuum and no water. that got us back to the RV park. When we got back I crawled under the truck and with a screwdriver to my ear listened to the frame pump. The whining was gone,but I could hear either a bearing or the pump cavitating. When I wiggled the engine side fuel line connection I could feel the vibration and could make it worse when moving it. It was the one nearest the frame with a yellow connector. I assume the yellow is the suction/ pressure side and the blue is return. My next idea is go back under the truck and try to find a leak between the tank and the pump, but Ford said they tested all the lines and all were OK. Any advice would sure be appreciated. I have given up on the local Ford garage.

 

I watched a video from a guy in Las Vegas showing how to bleed the air from a 6.7 fuel system instead of the cycling the key. Simple enough, just remove the return line from the filter on top the engine and turn on the key for a few seconds. I put a 1/2"id hose over the outlet so I could catch the fuel in a bottle. I had a friend turn on the key and sure enough a lot of bubbling and air. We did it twice and ended up with about a pint of fuel. Afterward he crawled under the truck and listened to the frame pump, no whining or bubbling noise. Yesterday you could feel the fuel lines jumping from having air in them. Cycling the key did not remove the air. I am hoping this will be the cure, but after I got it back from the dealer it was good for bout 800 miles.

Bottom line if you are having this problem try bleeding the upper filter, you know like we did before computers, DEF and all the POS they have added.