Urgent on the side of the road 1999 f250 7.3 starving for fuel at 1500 rpm
 

Ran fine all day, stopped at the light, idled fine went to accelerate acted like it ran out of fuel. Rail pump working, injectors are pumping oil evenly. Just need it to go 10 more miles. Truck will run 30 to 50 seconds at 1600rpm then start starving it's self. Let it idle for 2 to 5 minutes and it goes away until you take it past 1500 rpm again. Any clue?

I'd drain the fuel bowl for a minute in case it got a blob of something in the filter.

Also, how's your oil level? If it's on the edge of being too low the injection system is the first thing to lose oil pressure.

Check your oil level... if you are several quarts low, the injectors run fine at idle, but starve for hydraulic flow above 1,200 rpm.


You said your injectors are "pumping oil evenly". How did you determine this? In fact, what do you even mean by this?


With truck off, drain fuel bowl, open fuel filter cap, pull up the fuel filter and see if it is clogged with debris. Be sure to allow enough time to refill bowl electrically before cranking engine.

Oil level topped off I jumped out and pulled the valve covers. I know i have a broken internal clip on the valve cover harness drivers side so at first I thought that may be it. Turned out to be a little loose but not burnt or any oil inside the connection. So pushed them back together and let it idle seen oil pushing out evenly. Then thought about injectors so unplugged them each one by one with the covers off, and no change in the way it ran other than having an injector disconnected. I have a lot of tools with me just no pressure gauge to check pressures seems like 25-30 psi at the bowl bleeder. Fuel filter is clean and was changed last week along with oil. The way it behaves, it acts like it goes into a limp mode or something once it starts this. I'm beating my head again the street light right now maybe it will help.

How much fuel is in your tank? Are you on flat ground? I wonder if there is a mountain of debris under your pick up umbrella in the tank? Do you have the stock sender assembly or have you Hutche'd it?


As an aside, you and Tugly will have to have a race on who can pull valve covers the fastest. I'm impressed.

Gauge says 3/8 tankful, probably more like a 1/4 tank. Flat as Florida can be, completely stock from ford. I'm not like many on here. I keep this truck as clean and maintained as best as possible as it was my first new vehicle. I don't do the mods or tinkering that most do just because it has always exceeded my expectations for what I use it for. Mainly pulling my s10 out to the track and maybe a friend's dragster in a 38' enclosed trailer. 5000 pounds maybe. Today we were trying to beat the rains home no trailer running around 65mph stopped at the light tried to leave and it felt on it's face. I'm good at diagnosing a carb'd big block but this is all relatively new to me. As this is it's first stumper in the 308,000 miles I've had it

I'm leaning towards the mountain of debris under the umbrella. I'm gonna see if I can just limp her home on the shoulder as it around 10 miles and traffic is just about nonexistent. I cant thank you guys enough for the support just signed up after just reading along for about a year. And I will keep you posted on what it may be (with pictures). I'm going to pull the tank and start there and work my way forward. Who's the best tech support on here because I will want to ohm out all the electrical in the system and will need base lines for that. Along with other really technical info on the parts themselves.

Still here, trying to help you get those 10 miles home. It is possible your fuel pickup could be clogged, restricting fuel delivery to the pump. It may not be entirely blocked, as fuel seeps through at the low demand rate of idle, but higher demand, and the pump is starved.

Before jumping to that conclusion, review in your mind what you did to the truck today that could have created a change.

Did you plug in or unplug any wiring harness of any kind, no matter how seemingly unrelated?

I know you only have 1/4 of a tank, but did you buy any fuel today?

Do you have a jerry can in your truck that you can get some fuel in? How far are you from a fuel station and an auto parts store? Walking distance?

As a test, can you buy 5 gallons of fuel, and a rubber fuel line (quick, before stores close on you), disconnect the fuel supply line to the pump, temporarily connect your jerry can fuel supply (I can't think of an easy way to prime the hose without making a mess), and repeat your elevated rpm test to see if the engine maintains speed?

maybe he lost his fuel foot and it's sucking air?

Good point coax9952. Not unreasonable for the rubber umbrella (fuel foot) to disintegrate. It is 18 years old, and was designed before the diesel fuel refining process was chemically reformulated.

One of the motivations for suggesting the 5 gallon jerry can, even if purchased at a nearby store, is that if the alternative fuel supply test works out (which would rule out any electrical, idm, icp, ipr, cps, & pcm concerns), then he can happily dump the rest of the fuel in his tank, which might raise the fuel level high enough for the pump to suck off the higher fuel level without the foot extension in tact.

If you have the tools and something to make air pressure you can try disconnecting the fuel line at the pump or bowl and blow 10-15 psi air back toward the tank. If your screens are plugged it will clear them for at least the 10 miles.

I got fuel from my normal spot I'd say 3 days ago, ran my normal 1500-2200 rpm there and back. 75 mile round trip. Didn't touch anything before it started this. I live 30 minutes driving from anything so walking is out of the question in this case. I'm doing alright at 14 mph lol. I'll try the bypass you suggested just gotta get home first. Will 3/8 o.d. vinyl tubing work as a jumper hose? Just trying to think about what I have at home I can use.

Bill's note should accompany the Father's Day wish list sent to the spouse of every guy who has always wanted onboard air, but needed a reason to justify the expense, other than airing up tires, which can otherwise be done at a gas station.

SC... once you get home, you're either pulling your bed (8 bolts and a buddy) or dropping your tank, so you can check out and clean the screens of your fuel sender good and proper. No need to do my suggested test at that point.

When I dropped my tank, I found a small hill of rusted debris neatly piled like a pyramid under the umbrella. Not a mountain, not enough to cause any issues, but I could see where that hill was going if I didn't intervene.

I needed that laugh man thanks, I was just thinking about how I could spin this into if I only had an air compressor and air tools onboard. My birthday is next month and I was trying to think about how to spin it to my wife. But I'm smarter than that I'm getting my kids in on this one. Tell mommy that daddy NEEDS an air compressor for the truck. But I made it to the house guys. Going to get a Dr pepper and get started on this thing.