How to test fuel pressure?
#2
1998 to 2011 Rangers used 55psi fuel pressure when running
Not sure you will have a fuel pressure test port on a 2004 4.0l SOHC
If you do it should be on the front of the left or right Fuel Rail, looks like a Tire's Air Valve because that's what it is, a schrader valve. should have a screw on cap just like a tire's air valve
If you don't then no easy way to test fuel pressure
If you have a crank but no start then do 50/50 test(spray Quick Start into the engine)
If it starts and dies then fuel delivery is the issue
If it doesn't start then no spark so probably crank sensor issue
You should HEAR the fuel pump in the gas tank run for 2 seconds EACH TIME key is turn from off to on
Repeat off and on as much as you need to to determine if you HEAR IT or you don't, its not quiet, a HUMMMMM from behind the cab
If engine starts to stall out at highway speeds then change fuel filter, if no improvement change fuel pump
2004 will have PATS(passive anti-theft system), it turns OFF fuel pump and fuel injectors if activated, but there would be a fast flashing "THEFT" light on the dash telling you its activated
EDIT
Found picture: https://cimg4.ibsrv.net/gimg/www.evo...689b88b0f7.jpg
On the lower right are several "end caps" that have the schrader valve
On the lower left are the "end caps" without the schrader valves
You can swap a non-scharder valve end cap for one with the schrader valve
Ford may have them but wrecking yard will as well
Not sure you will have a fuel pressure test port on a 2004 4.0l SOHC
If you do it should be on the front of the left or right Fuel Rail, looks like a Tire's Air Valve because that's what it is, a schrader valve. should have a screw on cap just like a tire's air valve
If you don't then no easy way to test fuel pressure
If you have a crank but no start then do 50/50 test(spray Quick Start into the engine)
If it starts and dies then fuel delivery is the issue
If it doesn't start then no spark so probably crank sensor issue
You should HEAR the fuel pump in the gas tank run for 2 seconds EACH TIME key is turn from off to on
Repeat off and on as much as you need to to determine if you HEAR IT or you don't, its not quiet, a HUMMMMM from behind the cab
If engine starts to stall out at highway speeds then change fuel filter, if no improvement change fuel pump
2004 will have PATS(passive anti-theft system), it turns OFF fuel pump and fuel injectors if activated, but there would be a fast flashing "THEFT" light on the dash telling you its activated
EDIT
Found picture: https://cimg4.ibsrv.net/gimg/www.evo...689b88b0f7.jpg
On the lower right are several "end caps" that have the schrader valve
On the lower left are the "end caps" without the schrader valves
You can swap a non-scharder valve end cap for one with the schrader valve
Ford may have them but wrecking yard will as well
Last edited by RonD; 01-18-2021 at 06:54 PM.
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