my dads 89 7.3 will start right up like it is supposed to. it will run for a minute then die. it will crank and crank. then it will fire up in a few minutes. i think it is the lift pump losing its prime. any thoughts from yall.

 

LP probably has a small hole or crack in the bladder. More than likely the source of the problem.

 

I had the exact same problem when I first got my truck. The ULSD (tree hugger formula) is very tough on our fuel lines. My problems were the injector return lines where leaking. Take a close look at them, and I bet you'll see a very small amount of fuel seeping around the return cap/return line junction.

If fuel can leak out, air can seep in. You're injector pump is losing its prime. When you first fire it up, it runs- then dies...what you're doing is cranking the lift pump until you get fuel back into the pressure line. It's the same problem as having a hole in a straw.

Get a set of injector return lines, orings (for the cap) injector crush washers (probably won't need those unless you're replacing the injectors) return caps- all of this in included in a kit here:eBay Motors: 7.3 Diesel Ford Injector Kit, Fix Leak in Return (item 150311132439 end time Dec-20-08 06:00:45 PST)

 

mine does it on the front tank but not the rear im sure its got to do with the pick up tube if both are full does it start and stay running if the tank is below 1/4 it will ,anyway try starting it on the other tank

 

read flathead jacks post about staring the dying

 

I had the same problem with my 7.3 and it was the sensor on the front or the motor thats over the cam i dont know what its called but thats what it was. hope this can help.

 

we aint got no cam postion sensors!

 

that "sensor" is the tach sending unit..