I have 1988 f350 351 duel fuel ranks. Low fuel pressure ..new in tank pumps ..new out tank pump... Filter and reg are a year old... And new fuel pump relay ... Still low pressure and won't start..... Any help would be appreciated

 

Can you clarify a few things?
Exactly what is the fuel pressure reading you are getting ?
Are you sure there is an additional pump on the chassis rail ?
Did you check the power from the dash switch to the fuel pumps for any voltage drop causing the pumps to operate at lower power and therefore lower output? Both pumps share the same ground . Confirm the ground is clean and in good condition. Don't forget to check the connections at the inertia switch.
Many good pumps get replaced because all the connections were not checked.
Just because the filter was changed year ago is no guaranty the filter is not plugged.
If you have some carb and choke cleaner, spray a shot or two into the intake and see if the vehicle will start. If it starts, then a fuel problem, if not , could be a different problem.

 

Yeah, What Hanky said. Start with the ground connections as they corrode first.

 

Check drivers side frame rail near drivers door , there should be a high pressure fuel pump here.

 

Turns out was pcm

 

Turns out was pcm