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2001 Lincoln LS fuel pressure

Tiny
DIETER123
  • MEMBER
  • 2001 LINCOLN LS
  • V8
  • 2WD
  • AUTOMATIC
  • 10,900 MILES
First start of the day, 5-7 sec cranking time before engine starts. Diagnosis >>>> Key turned on, then off, fuel pressure reads (33psi) at rail then begins to drop slowly and within 10 minutes gauge reads zero. Fuel injectors were removed and shop said they were good. Fuel rail pressure sensor vacuum line show NO signs of fuel. Replaced fuel filter. Could the fuel pressure be leaking back (through fuel line) through fuel pump back into tank?
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Friday, October 22nd, 2010 AT 8:02 AM

11 Replies

Tiny
WRENCHTECH
  • MECHANIC
  • 20,757 POSTS
Yes, a bad check valve in the fuel pump will let it siphon back into the tank.
If you build up pressure and then pinch off the feed line you can find out that way.
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Friday, October 22nd, 2010 AT 8:51 AM
Tiny
DIETER123
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Wrenchtech, Thanks for your quick response.

I assume you mean "pinching" at the fuel pump? Can I gain access (and more than likely change the pump) from under the rear seat?
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Friday, October 22nd, 2010 AT 8:57 AM
Tiny
WRENCHTECH
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I mean pinching the line at any point it has rubber hose before the gauge.

Yes, this one can be access from the rear seat but most can't.
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Friday, October 22nd, 2010 AT 9:05 AM
Tiny
DIETER123
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Could not find a "rubber" portion of the fuel line to pinch off. I decided to just replace the pump. Still having the long crank before start issue. Please help.
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Tuesday, April 12th, 2011 AT 5:01 PM
Tiny
WRENCHTECH
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How long does it take for fuel pressure to get back to spec once the key is turned directly to crank?
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Tuesday, April 12th, 2011 AT 5:52 PM
Tiny
DIETER123
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Wow. Thanks for the quick response! The fuel pressure comes back within 5 seconds from the time the key is positoned to "crank".

BTW.I did remove the IAC. It was dirty, so I used Chemtol(?) Cleaner and reinstalled the IAC. Also checked the MAF for foreign/dirt. Blew on the MAF slightly to ensure it was clean.
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Tuesday, April 12th, 2011 AT 5:59 PM
Tiny
WRENCHTECH
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So, has it started by that 5 second time?
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Tuesday, April 12th, 2011 AT 6:03 PM
Tiny
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Yes
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Tuesday, April 12th, 2011 AT 6:12 PM
Tiny
WRENCHTECH
  • MECHANIC
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It starts in less than 5 seconds. Where's the long crank.
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Tuesday, April 12th, 2011 AT 6:16 PM
Tiny
DIETER123
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From my original post, I stated a 5-7 sec cranking time before start. I would have to agree with you that 5-7 sec does not seem that long until you actually look at your watch and simulate it. It is long when you compare most (healthy) vehicles fire right up at the initial crank command(as does this vehicle when I turn it off and immediately go to restart). Although I do not have a check engine light. Would a high end scanner reveal any issues I may be experiencing. Or do you have any other suggestions?
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Tuesday, April 12th, 2011 AT 6:33 PM
Tiny
WRENCHTECH
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I don't know what to tell you. I tried to give you a way to test it but you were unable.
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Tuesday, April 12th, 2011 AT 6:35 PM

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