No Fuel Pressure

[mark03expeditio]

Need Help!! 03 Exp. 4.6l. Engine idles rough. Hesitation. When I press the accelerator the engine cuts out like its starving for fuel. So I checked the fuel pressure. None. I turned the key on and listened for the fuel pump. It kicked on for a second or two then went off. The relay kicks, hesitates a second or two then kicks off. I replaced the pump and filter. Same results. I removed the vacuum line for the pressure regulator and it didn't change anything. Still no pressure. The engine keeps running though. I have no codes. I'm stumped on this one.

 

[toms89]

How are you checking fuel pressure??

It will not run without fuel pressure. If you turn key to run position without starting fuel pump will run appr. 2 seconds to build up pressure and stop. The fuel pump only keeps running while engine is running.

 

[mark03expeditio]

I know. I used a new fuel pressure gauge. I checked it on another vehicle to verify it worked when I got no reading on my valve on the fuel rail. So I have no fuel pressure at the motor. I used my knife and opened up the valve on the fuel rail and turned the key on. About a spoonful of gas came out.

 

[toms89]

My guess is the schroeder valve is not working correctly or your gauge is not depressing it fully. It cannot run with out fuel pressure or the engine would receive no fuel. Stupid question but you did remove the cap??

 

[mark03expeditio]

Yeah.

 

[toms89]

I can't see how she would keep running with zero fuel pressure but I could be wrong..

I would inspect the Schroeder valve carefully with flashlight and your gauge to insure it can fully depress it and make sure there is not some problem there.

Without some reading its hard to know where to proceed.

 

[stamp11127]

Thanks for the laugh Tom, I about fell out of the chair...."Did you take the cap off?"
Going on past experience they start dying around the low-mid 20's on fuel pressure - watched the gauge as she took the last breath.

You have some fuel pressure since it is running.

 

[toms89]

Thanks for the laugh Tom, I about fell out of the chair...."Did you take the cap off?"
Going on past experience they start dying around the low-mid 20's on fuel pressure - watched the gauge as she took the last breath.

You have some fuel pressure since it is running.

Was not trying to be insulting to the op but thought I should cover all bases. Who knows it may not be easily visible?

Mine will stall before I get anywhere near zero fuel pressure but she is very thirsty. Much larger injectors, etc..... I also have a fuel pressure gauge installed so its easy to monitor.

 

[mark03expeditio]

Well, I get about 2 ounces of fuel out of the valve. So that leads me to believe the valve should be okay. Unless I'm missing something. Guess I can check the pressure somewhere else?

 

[mark03expeditio]

I was wondering if the engine could be getting fuel back from the return line?

 

[stamp11127]

I think these are the returnless systems.

 

[mark03expeditio]

Great! I missed that. I used my knife to open the valve while the key was turned on and got a couple ounces of fuel. That was it. So what would you recommend I try next?

 

[stamp11127]

Check the schrader valve, the plunger needs to be straight and centered.

 

[mark03expeditio]

I will check it out. Thanks. May be a stupid question.... If my valve is not working correctly I wouldn't be able to accurately measure my fuel pressure.
that wouldn't mean I don't have any though. So what should I try? New pump and filter. no codes. rough idle and no power???

 

[01yellerCobra]

Is it possible to swap the relay with another one in the fuse box to rule it out?

Misspelling brought to you by tapatalk

 

[bedrck46]

The fuel pump relay on the 03 is a non serviceable relay it is internal on the circuit board in the fuse block although there has been many reported problems associated with this relay

 

[stamp11127]

The engine will not run without fuel and fuel pressure. Since it is running it has some fuel pressure in the neighborhood of 20psi. That also proves the fuel pump relay hasn't failed. The 20 psi pressure is enough to show on the gauge, so when your gauge is installed it is not depressing the valve in the fuel rail.

Before going any farther I would get a pressure reading from a second gauge and see if it is spec. If it is then you move on to diagnose the issue.

 

[mark03expeditio]

okay. I'm going to check the fuel pressure when I get off work. I'm assuming I missed the bad valve on the fuel rail, and I actually have enough fuel pressure. Especially since I have a new fuel pump and filter installed. I had some misfire codes, 4, 5 and 6. So went ahead and replaced the plugs and wires. Those codes went away. so if I have fuel and fire covered that leaves electrical and air. I checked all the fuses. They were good. Where would I look if my pressure is good. I'm thinking it's fine and I just missed the bad valve. MAF Sensor didn't help either.

 

[stamp11127]

Dirty throttle body, bad tps, egr system and the list goes on and on. How does it rev in neutral or park? If it starts having a problem hold it at that rpm to see if it will throw a new code.

 

[mark03expeditio]

I got a code for the egr valve stuck open. Can't remember what it was right this second.. I took the valve off and checked it. Sure enough it was stuck open. So I replaced it. Code went away. I have no power in any gear, park, reverse, drive. I can ease down on the pedal and get it to about 2800 rpm. I can hold it there for about 45 seconds. Then it starts cutting out on me. I did this for about 15 minutes. I got no code. It will idle quite smoothly around 750-1000 rpm.