I have an 02 7.3 with 65,000 miles. I programmed last week with a superchips programmer and it worked great for towing my trailer. [I] parked it and a week later when I went to start it, it shook and missed like crazy then shuts down. You can't touch the gas or anything or it will shut down. Once it does it takes a whule before it can be tried again. I removed the programmer back to stock and checked for codes (none were found). I've replaced the cam sensor, injector pressure switch, injector drive module, and just had the pressure regulator replaced within the last 300 miles. The truck has always had poor fuel economy at 12-13 mpg compared to my previpus 99 which got 23 mpg. I also can't get over 45 mph towing my 11,000 lb trailer over steep hills with it floored. Anyone have an idea what could cause a sudden change like this? I'm at the end of my rope and budget.

Thanks, Bill

 

Sounds like you need to find out what your high pressure oil system is doing. Here are two web sites with very good info on how it works. Diesel-Central.com the technical source for Diesel Truck information, Truck Pulling, and Drag Racing Trouble Shooter | Motor | Find Articles at BNET Our 2002 was giving us a fit and I used a dive regulator pressure gauge to check it. It turned out that ours had a bad HPOP and worn o-rings on the injectors.

 

Thanks, That is actually my last resort. I've also read that i might have a clogged pickup in the tank. If the fuel filter bowl cover is off and you crank the motor over, should you physically see fuel fill the bowl or does it only fill under a closed condition?

 

that fuel bowl should fill up in seconds.... normally you wouldnt even want to turn the key on with the fuel bowl cap off.... if its not filling, you definitely have a fuel flow problem... either the pickup in the tank is all plugged up, the fuel pump is toast, or a combination of both.... good luck man!

EDIT: also, the fuel pump is electric so it comes on when you turn the key on.... motor doesnt have to crank.... and it should be between 50 and 70 psi....

 

The in tank screen is large mesh that only filters out rocks and boulders then there is a unit with a thermostat in it to keep the fuel in the lines warm that has 2 smaller screens with a smaller mesh. It would be almost impossible for the primary screen to plug up. The 2 in the thermostat unit could plug but are cleanable.

 

Mine had a crack in the lower aftercooler line. Caused it to loose power instantly. Mark.

 

are the screens in thermostat the ones in the vertical tube inside the bowl? Also what exactly is the lower aftercooler? I appreciate all the feedback/ I took the bowl cover off again and turned on the ignition and even cranked the motor. The bowl simply isn't filling up. I checked the fuses (all were good) Tested all relays and they were o.k. also. I guess I'll drop the tank. I saw in my haynes book that the pump is located on the rail. Is this the fuel pump I should be testing to see if fuel pumps at this point by removing the line out and turning on the key? Thanks again.

 

Going to close the thread for now. Thread starter can reopen.