Fuel Pressure
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Joined: Aug 2000
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From: Richmond TX
Fuel Pressure
OK guys, just lookin to have you verify my diagnosis....was driving the car, when it just died....like it was out of gas. I had a full tank(yes, full, even at today's prices!). Tried to start it back up, but no go. My first thought was the fuel pump. Towed it home, and pulled the pump, since it is no problem. Found no problems....re-installed the pump, and tried to start it, but no pressure! Pulled the hose from the inlet side of the pump, and gas shot out at about 5gals/min. OK, check the filter...it's ok, but I replace it anyway...still no pressure. Pull the inlet connection to the fuel rail, and it gushes out fuel at the same 5gal/min. Humm....could the guage be bad?? Pulled the valve core form the schrader, jump the pump relay, and just a dribble of fuel. Blow out the fuel rail.....no blockage. connect everything back up....no pressure. This time, I disconnect the return line from the rail, turn on the pump, and nothing flows out the return line....where the hell is all that fuel going???Pull the dipstick, and the oil looks a little "thin". Guess it's goin' in the crankcase!!! My guess is the regulator took a dump?? Am I correct??
Thanks in advance....
Cheers,
Michael
Thanks in advance....
Cheers,
Michael
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Joined: Sep 2000
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From: The Top of Utah
From your description, it is too soon to condemn the regulator. If the regulator were blocked, plugged or not opening, the fuel pressure would be sky high at the Schrader valve. You have pressure and flow at the input to the fuel rail but not at the Schrader valve. From my parts book, it appears that the Schrader valve is ahead of the regulator. To me, that means some sort of a blockage inside of the right side fuel rail, or the feed tube you disconnected. I can't imagine what would cause that, but that is the way it sounds from here.
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From: Richmond TX
Originally Posted by CFI-EFI
From your description, it is too soon to condemn the regulator. If the regulator were blocked, plugged or not opening, the fuel pressure would be sky high at the Schrader valve. You have pressure and flow at the input to the fuel rail but not at the Schrader valve. From my parts book, it appears that the Schrader valve is ahead of the regulator. To me, that means some sort of a blockage inside of the right side fuel rail, or the feed tube you disconnected. I can't imagine what would cause that, but that is the way it sounds from here.
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From: The Top of Utah
Originally Posted by mk842766
My thoughts too, but I blew out the fuel rail, with no results. I'm thinkin the regulator is stuck open, dumping the fuel and not allowing any pressure to build up.....but I've been wrong before. I'll try the fuel rail again, and see if I can find anything.
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From: Richmond TX
Originally Posted by CFI-EFI
I wasn't thinking of the regulator dumping the pressure. Put a pair of vice grips on the flex hose of the return fuel line. If the fuel pressure jumps to above spec pressure when you energize the pump, you have your answer.
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From: Phoenix Arizona
Try pulling the injector fuses and pull your plugs. I can't imagine one injector dumping that much volume. Are you sure your pump is on during all of this? It only comes on for a few seconds,and then shuts off.
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From: Richmond TX
Originally Posted by zr1fred
Try pulling the injector fuses and pull your plugs. I can't imagine one injector dumping that much volume. Are you sure your pump is on during all of this? It only comes on for a few seconds,and then shuts off.
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Joined: May 2006
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From: Phoenix Arizona
I'll admit it, I'm stumped. If you have fuel pressure at the filter, at the inlet to the fuel rail, you should have it at the schrader, it's a strait line, the only way out is the fpr and the injectors. Check the plugs, they would have to be soaked. Sorry.
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From: The Top of Utah
You can't have injectors leaking that much fuel. If they were, the oil pan would be filling up and you would have gasoline flowing out of the exhaust pipes. Not to mention several cylinders hydro-locked. I'd be looking for a blockage. Strange.
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Joined: Jun 2004
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From: WI
Originally Posted by mk842766
Yep, tried that with no change....that's why I pulled the line off the fuel rail for the return....not one drop of fuel came out. The fuel is getting to the rail, but not getting out, so there has to be something going on at the rail. I have plenty of VOLUME getting to the rail, very little coming out the schrader valve, and NONE coming back the return line. It looks as if any extra fuel is getting pushed to the oil pan???......
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Joined: Sep 2002
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From: Boise ID
Did you check the pressure right out of the pump? Sounds like the pump has no problem supplying a volume of fuel unrestricted but when you present a restriction to create pressure, the volume drops off. Sounds to me like your pump is toast.