So I lost pretty much all power while on vacation this weekend. We drove about 150 miles, 90% highway, SES came on during the drive but no issues. Stopped at the grocery store, no issues on start up and leave, city streets at this point.

Sitting idle for about 15 mins while my wife fed the baby, the truck starts shaking pretty good and idling rough. I drove it down the adjacent neighborhood street and had no power. We ended up making to the hotel which was only a mile or so away at that point. Pulling onto the road, it would take 20-30 seconds to get to 35mph, with the pedal to the floor, it would get to 2500 rpms, then shift really hard, and continue to accelerate but still slow. It felt and had the bogging sound you get when you try to start in 2nd or 3rd with a manual trans.

So I changed the fuel filter which was absolute garbage but it was little help. I did ultimately make it home after the trip. Wouldn’t do over 65 on the highway with the pedal pegged the whole time. Sat high on RPMs too at 2500-2700 and wouldn’t shift unless I let off. Weird transmission stuff but I figured other culprits due to this wall starting at idle and no other trans issues at all in terms of shifting. Though it is the original at 367,000 miles.

Not my first choice to drive it back but no shops open on the holiday weekend and we had work Tuesday so we didn’t have many options.

So additional notes:
-I suspected the UVCH from reading the board. Pulled the valve covers when I got home, and neither of them were loose and had solid clips couldn’t pull out on their own if they wanted to.

-haven’t ran the code yet, don’t have a scanner (recommendations?)

- I got an SES light going to work a couple of weeks ago but it was gone when after I picked up the kids. Haven’t seen it again until this trip.

- I just changed the oil with Rotella T5 15w40. I did add Hot shot stiction eliminator to the oil due to some recommendations from others as I have been having mild hard starts when cold. Also the hot shot diesel extreme fuel additive.

- the day after the oil change we did a 300 mile round trip for the weekend with no issues or codes (this was after the initial intermittent code).

- sat parked for 2 weeks then this trip with the issues.

-this is our road trip vehicle. No and again I’ll run it to work but it’s mainly to tote the kids and dogs to my parents, in-laws, and vacation


Let me know what y'all think.

 

It will really help to have codes and be able to monitor pressures. You can get a dongle that plugs into the OBDII port and an app for your phone, Forscan. It will let you see many parameters like oil pressure, voltage, temps etc. It will also pull codes.

Get a dongle that is J1850 compliant. The unit you get will depend on your device, is it android or fruit(apple).

One thing our PCM's do not monitor is fuel pressure. You can do that on the cheap with some hose, clamps, and a 0-100 gauge. Plug the hose into the drain tube off the fuel bowl and open the drain. You'll need to check pressure under load, i.e. in gear and throttle applied. Idle fuel pressure isn't a good indicator as it will look ok but drop as soon as you load it.

Have you done the tank mods hutch and harpoon??

The SES light says you have more than a fuel issue going on but probably need to check it if you've never cleaned tank screens before.

Does the truck run better before getting up to temperature?? I suspect a high pressure oil leak like injector orings if they are original

 

^^^everything Paul said. Link to a how-to for FORScan - a very useful scanner

https://www.ford-trucks.com/forums/1...d-q-and-a.html

It does sound like you are not getting adequate fuel pressure, but need to confirm:

https://www.ford-trucks.com/forums/a...4&d=1592859516

 

Alright I just ordered a scanner that will be here Wednesday, thanks for the info and I’ll post the code when I run it.

Right now since this started, the truck runs better at temp. It struggles to start cold at all and stalled a couple of times cold starting. Sounds like crap cold.

Im going to say no on the tank mods. I’ll have to look into it as I am new to the 7.3 (bought this in December). But the original owner was an older guy that bought it new for their family ride. I have a composition book with all maintenance records and I don’t see anything in there.

 

Running better at temp kinda rules out leaking orings and leans more to worn out injectors. @HKusp may have more to add here. If this is the case others have had some temporary relief by running a 5w40 synthetic oil

 

My first thought was a fuel pressure issue, especially with the nasty filter find. Suspecting dirty in tank screens. But like others stated this shouldn’t throw a code (directly anyhow).

Like the others, I recommend doing a fuel pressure check.
https://www.ford-trucks.com/forums/a...4&d=1592859516

Hutch and harpoon mods should be on the short list of repairs even if that’s not the culprit.
https://www.ford-trucks.com/forums/1...l#post19216921

 

UVCH harness would be my guess more than fuel pressure. I ran dual egt gauges and was able to diagnose a uvch problem with a glance. One sides temp went through the roof while the other didn't move.

 

Hmmm dropping the fuel tank might be a mission I’m not equipped for, as it sits anyway, she’s sitting with a bout 30 gallons. I’ll check the pressure though, thanks.

That will throw a code right? I did pull the valve covers and checked the connections. Both clips were good and solid. I suppose it could be a failure and not a loose connection. I’ll have a code reader tomorrow and will report back.

I have seen other possibilities from my symptoms that needed, cleaning the FPR screen, failing ICP sensor, and/or a failing CPS sensor.

The common symptom being little to no low end power, like it is starving for fuel, then at 2500rpms it throws you into the back of your seat.

 

Good that you verified the UVCH is solid, that's a primary concern.

Getting the codes will help, obviously. A fuel pressure reading at idle and WOT would rule out that side of the diagnosis tree.

 

Looking at the uvch connections was a good call When they fail they usually fail internally if the connectionsare good.
When mine failed everything looked good and my connections were in great shape. I had 0 power anywhere and trying to get home in a 35 mph zone was a tall task.

 

Did you add fuel since/ after the problem started?
30 gallons of fuel would make the truck run better than 4 gallons, if you have clogged or damaged pick up screen aparatus.

 

I am still hoping the code reader tells me that it is the UVCH this evening.

This may be a dumb question, but can I fire up the engine with the valve covers off and idle for a minute to see if my fix corrects the issue or am I going to spray oil everywhere?

 

I've idled for an hour with them off in high idle, no mess. You'll be fine

 

I did add fuel after the issue. A little tough to estimate as the fuel gauge doesn't work on the truck. I normally just set the trip and fill up at 500 miles, even estimating at 14 MPG, which I know I get better, that puts me around 35 gallons usage with plenty of room left on the 44 gallon tank.

When I left for the trip, I admittedly got fuel at crappy looking station, though there was nothing else near by. Meter clicked at off due to hitting $75 (25 gallons) so it wasn't full but probably close as I was only showing about 300 miles on the trip. After the first half of the trip (around 150 miles) which is when the problem started. SES light was on before the fill up. Changed the fuel filter and I filled up before we left too. Not sure why, but I guess I thought if it was bad fuel, adding good fuel may help? Not a mechanic or have any reason to believe that to be true but it was my logic.

 

Is there an add on or replaceable fuel filter under the driver's compartment attached to the frame rail?

If so, change it, but be aware of fuel pressure issues.
You may need to read up on that.
I do not know the correct procedure.