fuel problem, cummins
 

I have a 96 dodge with the p-pump. well i've been noticing lately that if you try to keep a constant speed at above 65 it starts to shake and sputter until you back down under 65 then runs strong. and when i shift through the gears i'm not lacking for fuel and it's not smoking white just black. i haven't been able to find a fuel leak until today when i noticed fuel coming from my injector cup. I was wondering if i could just tighten that up and be ok or do i need to do something else. i really need some help on this one soon as i don't like the fact of a fuel leak that close to my exhaust. especially since i have to drive it at least 50 miles a day to work and all. thank ya'll Zach West.

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also the fuel is leaking 4 out of the 6 injectors. this problem didnt start until i put a different injection pump in either. there is no other fuel leaks in the system.

Did you make sure and tighten all the lines correctly?

ya i loosened them and made sure they were all straight and seated and they are. my brother thought that it might be the return lines but its not they are all tight and not leaking any

This could be part of the problem - have you ever replaced your rubber fuel lines? Just because it isnt leaking doesnt mean you dont have a leak. The fuel line develops very tiny holes that are small enough to let air in and not let fuel out. Do not use regular gas rated hose.

Dr. Evil is correct. Those lines are notorious.

The next thing I would ask is how long since the fuel filter what changed?

Do you have the ability to check fuel pressure?

You say none of these problems came about until after installing a new P7100. Did you replace the overflow valve on the pump with a new one or did you reuse the old one?

i reused all of them i asked my brother he said the copper washers on the return lines might have gone lost their spring. i tightened the bolts and 2 of them stopped leaking i was wondering if this could be part of the problem. and the fuel filter was changed bout 1000 miles ago when i changed my oil after the pump change. and i can check the fuel pressure at the shop at my college.

Never reuse the copper washers - they are cheap enough to replace every time.

To check fuel pressure you need to tap the bano bolt on the inlet of the P-7100. Use a 1/8" tap and an R drill bit - its should look something like this (dont forget to install a needle valve to act as a pressure snubber):

Attachment 49259

i never took them off i guess they haven't been changed in a while and thank you for the pic. what fuel pressure should i have there?

22-25 psi at idle and just over 30 at WOT.

alright thank ya i'll get that checked out in class tomorrow we have fuel systems anyways