fuel issues ----- i think
#1
05-06-2016, 06:41 AM
fuel issues ----- i think
***please help**first I want to thank everyone in advance for their advice. 2001 expedition with 5.4L engine eddie bauer with 94k miles
symptoms: on first start of the day after sitting all night, it starts after 5 seconds or so of cranking. it runs rough and idles up and down for nomore then 20-30 seconds. after that, runs like a new one all day.
after sitting all night, I hooked fuel pressure guage up to Schrader valve on fuel rail (which I am assuming is the Schrader valve on passenger side fuel rail) and pressure reads zero. I turn key to on position and pressure jumps to 35 psi. it then starts to drop at a steady slow pace all the way back to zero. no leaks in pressure guage setup..If I start the suv, pressure jumps to 35 psi and maintains. if I hit gas fast and hard, pressure jumps to 40 psi then falls back to 35. if I remove vacuum from what I thought was fuel regulator(looks like regulator that is built onto fuel rail), pressure jumps to 45 psi and stays. when I hook vacuum back up, pressure drops to 35 and stays as longs as expedition is running. shut it off, pressure starts dropping toward zero. if I remove pressure guage, shut engine off and push in on the Schrader valve needle, no gas at all comes out. if engine is running and I press on needle of valve, gas shoots out. Only other issue is small antifreeze leak where quick connect on hose connects to front heater core. which is a different question all in itself.. is this a returnless fuel setup with no fuel regulator? if so, should there be pressure in the system when everything is off? If i hit Schrader valve with everything off should I get more then just a little fuel dribble at best?...where do I go from here and what could be the issue here?
thanks for all your help. at 42 years old, decided to get me a good used ford.
symptoms: on first start of the day after sitting all night, it starts after 5 seconds or so of cranking. it runs rough and idles up and down for nomore then 20-30 seconds. after that, runs like a new one all day.
after sitting all night, I hooked fuel pressure guage up to Schrader valve on fuel rail (which I am assuming is the Schrader valve on passenger side fuel rail) and pressure reads zero. I turn key to on position and pressure jumps to 35 psi. it then starts to drop at a steady slow pace all the way back to zero. no leaks in pressure guage setup..If I start the suv, pressure jumps to 35 psi and maintains. if I hit gas fast and hard, pressure jumps to 40 psi then falls back to 35. if I remove vacuum from what I thought was fuel regulator(looks like regulator that is built onto fuel rail), pressure jumps to 45 psi and stays. when I hook vacuum back up, pressure drops to 35 and stays as longs as expedition is running. shut it off, pressure starts dropping toward zero. if I remove pressure guage, shut engine off and push in on the Schrader valve needle, no gas at all comes out. if engine is running and I press on needle of valve, gas shoots out. Only other issue is small antifreeze leak where quick connect on hose connects to front heater core. which is a different question all in itself.. is this a returnless fuel setup with no fuel regulator? if so, should there be pressure in the system when everything is off? If i hit Schrader valve with everything off should I get more then just a little fuel dribble at best?...where do I go from here and what could be the issue here?
thanks for all your help. at 42 years old, decided to get me a good used ford.
Last edited by n.shift; 05-06-2016 at 06:45 AM.
#2
05-06-2016, 12:56 PM
There several variations of fuel pressure regulation among which were conventional, early mechanical returnless, late mechanical returnless, electronic returnless.
If there is a return line to the tank it should be a conventional system with a visable fuel regulator on the fuel rail.
The mechanical returnless has no pressure regulator at the fuel rail, no return line from the rail to the tank,and has a pulse dampener at the end of the fuel rail (is often mistaken for a pressure regulator).
The electronic returnless fuel system has a pressure regulator in the fuel module in the tank that is controlled by a fuel pump driver module.
If there is a visable return line, you might try clamping it off and see if the pressure still drops with the key off. If it does, the check valve in the tank module is defective. If it holds, then the regulator is defective.
If there is a return line to the tank it should be a conventional system with a visable fuel regulator on the fuel rail.
The mechanical returnless has no pressure regulator at the fuel rail, no return line from the rail to the tank,and has a pulse dampener at the end of the fuel rail (is often mistaken for a pressure regulator).
The electronic returnless fuel system has a pressure regulator in the fuel module in the tank that is controlled by a fuel pump driver module.
If there is a visable return line, you might try clamping it off and see if the pressure still drops with the key off. If it does, the check valve in the tank module is defective. If it holds, then the regulator is defective.
#3
05-06-2016, 01:07 PM
There several variations of fuel pressure regulation among which were conventional, early mechanical returnless, late mechanical returnless, electronic returnless.
If there is a return line to the tank it should be a conventional system with a visable fuel regulator on the fuel rail.
The mechanical returnless has no pressure regulator at the fuel rail, no return line from the rail to the tank,and has a pulse dampener at the end of the fuel rail (is often mistaken for a pressure regulator).
The electronic returnless fuel system has a pressure regulator in the fuel module in the tank that is controlled by a fuel pump driver module.
If there is a visable return line, you might try clamping it off and see if the pressure still drops with the key off. If it does, the check valve in the tank module is defective. If it holds, then the regulator is defective.
If there is a return line to the tank it should be a conventional system with a visable fuel regulator on the fuel rail.
The mechanical returnless has no pressure regulator at the fuel rail, no return line from the rail to the tank,and has a pulse dampener at the end of the fuel rail (is often mistaken for a pressure regulator).
The electronic returnless fuel system has a pressure regulator in the fuel module in the tank that is controlled by a fuel pump driver module.
If there is a visable return line, you might try clamping it off and see if the pressure still drops with the key off. If it does, the check valve in the tank module is defective. If it holds, then the regulator is defective.
#4
05-06-2016, 03:07 PM
ok. now I guess im confused on what type of fuel system I even have. so basically if its a returnless system, then there will only be one fuel line coming from tank correct? I have look everwhere for a mechanical fuel regulator and I just cant find one. what I thought was a fuel regulator is not. it looks like one that is built onto the fuel rail and cant be removed. it does have a vacuum line running to it tho. its a 2001 ford expedition eddie bauer edition with the 5.4L engine. how many different fuel system did ford use in these rigs?
Last edited by n.shift; 05-06-2016 at 03:10 PM.
#5
05-06-2016, 04:24 PM
I believe what you may be looking at is a pulsation damper. If there is no return line to clamp off it is a returnless system and it most likely has a defective check valve in the fuel pump module,,,,,,in the tank. Until you make a decision, you might try turning the key on, then off, then back on a few times to get the pressure up then go to the start position and it should start much sooner.
Ford as well as some other manufacturers makes changes during the model year and you could have 3 of the same vehicles and have possibly 3 different systems.
Ford as well as some other manufacturers makes changes during the model year and you could have 3 of the same vehicles and have possibly 3 different systems.
#6
05-06-2016, 07:03 PM
ok. ill check it out and let you all know what I find. regardless of what type of setup I have, is it safe to say something is going on since I have little to no pressure at the schader valve with key off?
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