Okay what does it mean when the KOEO off fuel pressure for my 94 4.0 is low 17-20 (specs 35-45) but the KOER is normal 30-32 (spec is 25-35).
Pulling the vaccuum hose off the regulater while running gives me 40 and using a vaccuum pump at applying 10 inches hg manually it lowers to 34.
The engine vaccuum source has about 17 inches hg of vaccuum.
Does this point towards the filter?

Thanks
Rodman95

 

Without knowing more details about how you tested the KOEO fuel pressure, I wouldn't draw too many conclusions from low KOEO fuel pressure. It could simply be that the brief 1-3 s that the pump runs when the key is first turned on wasn't enough to fully pressurize the fuel rail.

 

Abbreviated Haynes procedure:

1. Relieve the pressure.
2. hook up fuel gage
3. ignition on (engine off)
4. watch system pressurize ,max out and take reading

I ran the test twice and let the pressure come up as high as it could and sat and watched it .

 

Your abbreviated procedure leaves out 3a) ground fuel pump test lead in self-test connector. This causes the pump to run continuously instead of for the brief couple of seconds that it normally runs when the key is turned on. This allows you to really see if the pressure is coming up as it should. AFter the pressure comes up, you can then turn the pump off and perform a leak down check. The fuel pressure should remain within a few psi of the KOEO value for at least a couple of minutes.

I would suggest you review the fuel pressure test procedure Ken00 wrote up and posted in his tech info post at the top of the BII and Ranger forums.