I have a 2000 F350 cab/chassis with a 7.3 powerstroke and automatic tranny. The vehicle does have close to 400k on it but has had routine maintenance and rebuilds along the way. Here is my situation: (sorry for the long details)

We were towing a trailer out to the west coast from the midwest. Around Utah the vehicle started having trouble pulling long uphill grades. It got to a point were we could only maintain 10-20 mph. Eventually we had to stop and let the truck rest to catch up. We got it to a mechanic and they ran the codes and tested the fuel pressure. It came back with a low fuel pressure/injector issue. We replaced the fuel pump on the frame and all the codes cleared out. We ran it another 1000 miles through the mountains without problems. On our return trip through the Rockies we had the same problem. We assumed that the new pump had gone bad. We replaced the pump and filter but it didn't help much. We go the truck to Denver and had a mechanic run the diagnosis again. He came back with one bad injector #4, a bad fuel pump, a torque convertor clutch switch being stuck and a bad variable speed sensor reading. He wanted to tear about the whole fuel injection system at the cost of $5000. I purchased another fuel pump from AZ. Replaced it and the truck ran great for 80 miles (topping 75mph along the way) and then... nothing. The truck will idle and get up to about 15 miles an hour but has very little power. We had to leave it in Fort Morgan, CO until after the holiday. My questions are this:

Could ONE (1) injector really retard the engine so much that it would not run?
Is there a diagnostic machine that can trace bad grounds/circuits/wires (not just the standard OBDII)?

I am assuming that we have a wiring issue. I am thinking everything runs fine until we hit a bump and the vehicle loses a connection. Are there any good wiring diagrams around for these trucks? Does anyone know of a GOOD diagnostic technician in the Fort Morgan, CO area?

If I can't get this truck figured out then I will have to find a truck and tow bar to get it home to Chicago. Really want to get this figured out. Any thoughts or suggestions are appreciated.

 

If you lose one injector, you lose 1/8th the power of the engine. I routinely work on trucks that have up to 4 injectors not working, and although they obviously lack power they are driveable.

The fuel pumps on these trucks are generally very reliable, there is no way you have had three bad pumps in this short of time.

Has the fuel pickup in the tank been inspected for obstructions? Very common problem, especially with high miles and will result in the symptoms you describe.


Jay

 

Welcome to FTE

Like Jay said, drop the tank and check out those little screens inside the mixing chamber. Plugged screens will cause a fuel restriction, and can even kill the fuel pump. Most of us do the in-tank mods to prevent this from happening. Welcome to guzzle's In-tank Hutch Mod Web Page

Your cab & chasis will be a little different. If you have a metal tank, there have been problems with the coating flaking off the inside and plugging the pick up foot. I would think if it was a coating issue, it would have shown up before now, but you never know.

 

I pulled the sending unit and the pickup screen was clear. That whole unit was replaced about 12 months ago. Could the fuel injector pump or module cause the symptoms I am describing? Or would the truck simply stop running if those were bad? Also, there is NO black or white smoke out the exhaust, if that helps. I really appreciate your help.

 

Need some clarification - Is there ADDITIONAL screens in the pickup BESIDES the pickup foot?

 

Yes, there are 2 cylinder screens inside the mixing chamber (white plastic thing)

Clean, they are supposed to look like this.

 

i had a 7.3 with 497,000 on her she did all kinds of crazy things. no why ? she had 497,000 on her.

 

Thanks for the info F350-6. I pulled the sending unit and checked the pickup. Did not realize there were additional screens inside the mixing pump. On the cab/chassis setups, 8 bolts remove the sending unit from the top (truck has no box on top) so there isn't even a need to drop the tank. I will check this out. It makes sense that a screen is plugged because letting idle refills the diesel sump but under load not enough gets into the sump before the engine uses it up. Really appreciate the insight. Will update later if it was the problem.

To Sandmanf250: 497,000? Good, I have about 100k left before she goes crazy. lol