Help!! 7.3 IDI NA

Truck is not getting up to speed and it can be to the floor and it wont go anywhere. Please help. New gp's & injectors. I am thinking the lift pump.

We need some more information on your truck, auto standard, year?

Lift pump is a possible cause. Is it smoking? Did you replace return lines when you did the injectors? Did you retime it after replacing injectors?

Yes, more information definitely needed. When exactly did it start behaving this way?
Are the tanks at least half-full, filter new and clean, timing set?

>Truck is not getting up to speed and it can be to the floor and it wont go anywhere

Well, as the owner of a 7.3 IDI NA, that is not unusual

It also might matter where you got your new injectors.

Mine was like yours, a combination of horribly wrong timing, a bad fuel filter, and a very dirty fuel system were the primary issues on mine.

Also what kind of glow plugs did you put in? Lots of people here have had problems with anything other than motorcraft glow plugs.

And WELCOME TO OB!

Your injector pump could be weak too. If nothing else, you could try to advance the timing to see if that makes a difference.

Nah, i'd check fuel filter first. Then lift pump next. Then, install a pressure gauge on the filter head and verify pressure under load - you might well have a partial blockage in one of the lines to the tank.

I was just throwing out another option.

My supply/lift pump is on a three way switch. I can have it run when there is engine oil pressure, always, or never. A couple times I have had it turned off, forgot it, drove off, and the engine didn't seem to notice.

The fuel filter is another matter. Is your plugged filter light working?

Same thing happened to me. Go pedal to the floor and barely enough power to crest a hill. Mine ended up being a worn out injector pump. I advanced the timing a dime width and it lasted just long enough to have the remanufactured ip delivered. After the replacement and retiming she was back to normal. One of the things I noticed before it crapped the bed was white smoke while coasting, especially down hill and I mean like a mosquito foger! Mine is a 94 with factory turbo and e4od. Had about 320,000 miles on the factory ip, which was about 220,000 miles over due for replacement. Don’t freak out man, there are lots of good folks here with knowledge to share willing to help. The more details you can provide the better though. I think your new injectors are requiring more pressure to pop than your old ip is used to with the old equally worn injectors. What’s the mileage on your ip? If it has the original grey paint from Navistar then it’s probably way over due.

The way that I read your original post, correct me if I’m wrong, everything was running fine until after the replacement of all eight injectors and glow plugs. Is this correct, or have you replaced the injectors and gp’s attempting to remedy the lack of power? If it’s the latter then you have a bit of trouble shooting to do before you reload the parts cannon!