4.0l Fuel Pressure

[natecrep]

Can anyone tell me:
a) if these two year engines fuel pressure requirements are actually correct
and
b) why there would be such a difference between the two year models


2001 4.0l fuel pressure is 30 psi min and 45 psi max
2002 4.0l fuel pressure is 40 psi min and 65 psi max

My problem (other thread) basically is either a vac leak or not enough fuel.
My truck is actually a 2001 but it has a 2002 engine in it that has been working fine for over a year. I'm wondering if this might be my problem since I have 32 psi at idle. Seems like the pressure range I have for the 2001 is wrong, I would have expected the 2001 to require like 60 psi also? Huuummmmm??

 

[ncranchero]

What is the production date or the VIN of the vehicle ? Or, is (was) the vehicle a Job 1 or Job 2 2001? Did you do the engine swap or buy it after it was done? Is the 2002 engine from a Sport/Sport Trac or a 4-door Explorer or ?? Ranger?

A lot of variables unknown to us as to what you are working with. Need more info.

You need a scanner that will read fuel trims.........

There are fuel "Return" systems and "Returnless Systems", both electronic and mechanical.

CHECK FOR UNMETERED AIR LEAKS
Fuel calculations can be affected by unmetered air leaks.

Carefully inspect the following areas for potential air leaks:
Hoses connecting to MAF sensor assembly.
Hoses connecting to throttle body.
Intake manifold gasket leaks.
PCV disconnected.
Vacuum lines disconnected.
Improperly seated engine oil dipstick, tube, and oil fill cap.
Exhaust leaks at flanges and gaskets.

 

[roamer37]

Can anyone tell me:
a) if these two year engines fuel pressure requirements are actually correct
and
b) why there would be such a difference between the two year models


2001 4.0l fuel pressure is 30 psi min and 45 psi max
2002 4.0l fuel pressure is 40 psi min and 65 psi max

My problem (other thread) basically is either a vac leak or not enough fuel.
My truck is actually a 2001 but it has a 2002 engine in it that has been working fine for over a year. I'm wondering if this might be my problem since I have 32 psi at idle. Seems like the pressure range I have for the 2001 is wrong, I would have expected the 2001 to require like 60 psi also? Huuummmmm??

2001 has a fuel return system on it would have had return lines to the tank from the fuel rail at the fuel rail pressure control...
2002 no return system different fuel pump fuel pressure is controled by the processor controling fuel pump voltage.. as lone as fuel rail and injectors were changed at the time of the swap all is good with pressure..