hello, i recently picked up my 1989 f150 xlt lariat with the 4.9 and its been having issues running since i bought it. i thought i had fixed the problems and then the car stalled out while i was driving it and i had to get a tow since it would not start up again. i did a fuel preassure test and got about 43ish psi KOEO and 38psi KOER while the required amount is 50-60psi while running so i replaced the high preasure fuel pump and fuel filter that are mounted on the chassis. to replace the part i had to cut and solder the connecter, the original fuel pump had a connecter running from the engine harness to the pump which used spade connecters to connect the pump, the new pump used o-ring terminals. i cut and spliced the o ring terminals to the engine harness connctcter and installed it but now im getiing no fuel preasure at all. is it normal for me to have to modify a new part, i got it off rockauto and it was motorcfaft so i though thered be no issues replacing the part.

 

The pump was running before replacement, so I would suspect you did something wrong with your wiring. You should not have to modify the pump in any way.If you didn't solder your splices, I would look for poor mechanical connections you made.

Check to see if you have power getting to the pump. Maybe a fuse blew.

 

i soldered the connections using 60/40 tin lead solder and used shrink wrap to seal the connection. i also confirmed the pump is getting power by using my multimeter and i got 12v when testing from the connecter to the electrical harness, i can hear the pump prime when i turn the key to KOEO.

 

The fuel pressure you were getting is not low enough to prevent the truck from running. But like raski said, make sure you are getting power to the new pump.

 

i verfied im getting power at the fuel pump electrical connecter and i can hear the pump priming when i turn the key to the on position.

 

Well, is it wired backwards?
If wired correctly and the pump runs but no pressure, maybe the vane is broken in the bottom of the new pump?