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Guys I am need of some help. I am going to give the complete history so this post will be long but probably helpful to helping diagnose.
I have a 2003 Excursion 6.0 that I bought in January with 214,000 miles on it. No upgrades have been performed that I knew of when I bought it. Truck ran great until April at 219,000. The truck started losing power on the highway. Would be fine once I got off the highway and did fine around town. I replaced the fuel filters and the problem remained. I ordered an upper fuel cap with pressure testing port. I checked the pressure at WOT and the pressured dropped like a rock. I put a blue spring kit in and the pressure was fine after several WOT tests. I also changed the oil at this time and used Amsoil 15W40 Marine and Diesel Oil.
Truck ran fine until I went to the mountains in mid-July. The EOT was hitting 235 on the hills and deltas had been 20+ at times before the trip but I was trying to hold out on the oil cooler until the fall. Well clearly I shouldn’t have done that. I had to pull off and let the truck idle quite often on long hills. But I made it back home. But I didn’t end up with a bad #7 injector on the way home. Also on the way home it started to lose power again on the highway but I wasn’t sure if that was due to the high EOT during the trip and way home.
I ordered a Ford Oil Cooler, Bulletrpoof Diesel Oil Cooler, Sinister Diesel Oil and Coolant bypass kit and did another oil change with same Amsoil. I did the coolant flush prior to the work. All the install went great. I felt pretty good when I cranked up after I was done. Felt a little overwhelmed at times as this was my first major job on a diesel. My brother helped me quite a bit throughout the project. At this time I had 225,508 on the truck. I also sent off a sample of oil to blackstone.
The truck ran fine but was still losing power on the highway. I put together a gauge that I could mount to my windshield and monitored the pressure and sure enough pressure was dropping like a rock again. It would go to zero and stay there barely recover. I figured since I had done the blue spring kit and filters 6500 miles ago it must be a weak pump. I was able to find a pump only replacement for $180 but was a Delphi. I installed and no change. Next I pulled the filters and they looked horrible. They were an off brand and I replaced them with motorcraft filters. Pressures were great I was happy.
Two weeks and 500 miles later I was pulling a car down to Wilmington, NC. I was a little over halfway and noticed the power on the highway dropping. So I pulled over and installed my pressure gauge and sure enough pressure dropped like a rock to zero and I would pull over and took a few minutes to recover back to 60psi. Was running horrible throwing codes for contribution balance. Frustrated I limped to the nearest O’Reillys and bought fuel filters. Pulled the bottom filter and it was nasty. Put the new filter in and she ran great, pressure perfect. Finished the trip dropped off the car and picked up a jeep and headed home. So the filter only lasted 500 miles I thought that was crazy.
Truck ran fine for a few weeks and the on a date night with my wife to Raleigh (about an hour drive for us) the hwy power loss started up again. I limped my way to our destination and took backroads home. Pressures were fine around town. I went ahead and grabbed some new motorcraft filters. Pulled the filters upper and lower and they were nasty so I replaced them. Pressures are back fine again. The filters had about 1300 miles on them.
I guess I must have some bad trash in the tank?? I guess I am going to have to go and get the tank cleaned this week. Anyone have any other ideas?
On a side note I have installed a Glowshift 100psi Elite pressure gauge in the fuel pressure test port on the housing. I still have the mechanical gauge on my windshield. From my understanding my mechanical gauge connected to the filter cap is measuring pressure before the filter and Glowshift is measuring pressure post filter. Is that correct? I have noticed the mechanical gauge reads around 60 idle or cruising but the Glowshift reads 60 idle but about 50-52 cruising. Also at WOT the Glowshift drops to close to 40 but the mechanical is only about 50? Trying to figure out why the difference.
Blackstone Comments: Thanks for the notes. We might find some wear-in metal next time from the parts you just replaced, but wear looks good in this sample from your 6.0L. Better than average, really, and our averages are based on a run of about 5,600 miles. Our one concern here lies with fuel. 3.5% is cautionary, but cold sampling can also leave fuel in the oil. Watch for a rising oil level, and let's see if fuel sticks around before calling a problem. A thin viscosity is normal to see for these engines, and fuel can cause that too. The TBN is strong at 6.8. Check back in about 7,000 miles.
I have a poly tank. I forgot to mention that around the first time i had the pressure problem and before the blue spring I saw a video about some filters in the tank that get clogged up so i had my brother drop the tank to clean them and found out i just have a screen on the bottom of the pickup but no internal filters.
In thinking about this I think in both cases they take the readings from the same side
of the filter.
I'll have to go take a look. But the pressure port in the cap that you are using
sits in the cage at the top of the filter and the pressure test port is also on the
outside of the filter. The filter has a seal in the lower end that the stem fits onto
and the stem is screwed down to the base with a seal between it and the base
where the 2 ports are at.
I have thought about bad fuel but I always fill up at my local BP and one time was at a Speedway in Boone. However, my brother always gets his fuel at the same BP and was with me and got fuel at the Speedway in Boone and he hasnt had any issues, he has 02 F250 7.3.
Yahiko, thanks for the info. I was just thinking may the difference in readings was pressure drop across the fuel but i wasnt sure exactly how the fuel flowed.
Sean is right, both locations monitor pressure that is to the exterior of the secondary filter. To monitor pressure on the fully filtered side you would need to tap into one of the banjo bolts or tubing to them.
If you've had that often a fuel delivery problem with dirty filters, I'd be pulling that tank and clean it out to get that possibility off the list. It would only take one fill up with algae contaminated fuel to keep things nasty in there. Every fill up feeds the beast with fresh food.
Do the hutch and harpoon mods while you're at it. That way you can fill the tank to the top with the algaecide. Do it for a few tank fulls and you should be good to go. Same thing happened to me, only I caught it before I had real bad loss of fuel flow.
