2003 Explorer Sport Fuel Pressure

[tomlogan]

My 2003 2 door Explorer Sport is hard to start - excessive crank. I have changed the fuel filter, plugs, and plug wires - no change. Note that this is a 2 door Sport model, not a sport trac - and entirely different than the 4 door model for the most part. When I bought the fuel filter - there were 2 types - one with 3 lines and one with 2 lines. Mine has 3 lines. I have a fuel pressure guage connected and it reads about 30PSI. My question is - What should the pressure be? I see some posts stating that the pressure is in the 65PSI range and some stating it is in the 30PSI range. Which is correct? - or is it dependent on the number of lines that the fuel filter has? It would seem that the number of lines on the fuel filter indicates that there was a pretty big change in the fuel system for this year/model. Any opinions??

I should also add that I have the Ford service manual for this Explorer and it states 65 PSI - but I am not convinced this is correct - especially if there are 2 fuel system designs on this model. It seems add that I would have 30 PSI on a vehicle that had 65 PSI new. The truck runs great at any speed - just hard to start

 

[Vladvo]

65 +- 8 PSI for 3-line filter. 2003 Exp Sport. 4.0L , VIN E from another repair manual.

Ever tried to turn ignition key on and off a few times before starting the engine ? This way you could sorta add fuel into system before starting.

Another thing to check is the fuel pressure regulator. And the fuel pump itself. Where you installed the pressure gauge ? Does the car act the same without the gauge ?
I am not sure about it, but i think it could be possible to connect some kind of pressure gauge =before= the filter. This way you could be sure if this is a fuel pump issue. The pump specs are the same (65 +- 8 PSI). If you have them before the filter - obviously it's not the pump.

 

[tomlogan]

I did some more testing today - very odd results. If I turn the ignition on and off multiple times after the car has been sitting for some time, the pressure will not rise until after the vehicle has been started - then it holds at about 30psi. I pulled the pump relay and shorted across the terminal to energize the pump and the pressure went up to 30 psi. I put a switch on the across the terminals so I can manually control the pump and then noticed the pressure was still at zero after the vehicle sat for a while - with the switch on. I did some voltage measurements and it seems with the car running I have 14 volts - normal. When I shut the vehicle off the voltage drops to 12 - still normal. BUT - after the car sits for a few minutes the voltage drop to about 9.5 which seems to be enough to run the starter without any trouble - but not enough to run the fuel pump. I am going to connect it to my wife's battery in the morning and see if the pump gets the pressure up before starting the car.

I'm still dubious about the correct pressure as something changed in the middle of the year - what is the design difference between the 2 line filter and the 3 line filter? I'm wondering if the manuals came out and Ford switched the design in the middle of the year - it just seems odd that I have 30-35psi which is the normal pressure used in some Fords.

I am checking the pressure at the scrhader valve - near the firewall on the passengers side. Should the pressure be 65 here - or directly out of the pump - I have no idea what components are between the pump and that schrader valve.

 

[tomlogan]

I just paid for the Haynes on-line manual for this suv and the fuel pressure there is stated as 30-65psi. The ominous part of this figure is that the year range for this figure is 1999 and later. So, I'm not sure I really learned anything from this.

Does anyone have a fuel system diagram for this exact SUV (2003 2 door Sport - NOT sport track)? I would at least like to know what components I have - like is there a pressure regulator and where is it if there is?