Fuel Car sputters and throws a P0190 code

Discussion in 'SN95 4.6L Mustang Tech' started by mikemora01, Jan 7, 2013.


  1. mikemora01

    mikemora01 New Member

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    Hi all my car for the past month or two has had a sputter when driving at low rpms. The last few days the low rpm stutter has smoothed out and the car now bogs and sputters really bad at anything over 3000 rpm. The car will not drive at highway speeds anymore it just sputters and stalls. The car was throwing many codes at first but now is consistantly throwing a P1000 and P0190 code which says fuel rail pressure sensor when i look it up. but has a list of things that could be the problem including the sensor itself. I do not know much about this sensor and what it does so i tested my fuel pressure on the rail and it is reading low at a constant 28 psi. Does any one know if this sensor can effect the fuel pressure and could be the problem or is it my fuel pump. I have changed the fuel filter within the last six months and also have a walbro 155 fuel pump. my car is a 2001 mustang gt sohc.
  2. Bob Hughes

    Bob Hughes Member

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    The sensor tells the fpdm how hard the pump should be running, so yes if the sensor is bad could throw bad readings to fpdm. What's pressure at rail when you first key on, prior to start?


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  3. mikemora01

    mikemora01 New Member

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    When i turn my key to the on position i can hear my fuel pump kick on but my fuel pressure reads 0 at the rail. The car then fires right up and the pressure jumps to 28. I read that fuel pressure should be steady at 30psi at idle is this correct and is 28psi an exceptable number?
  4. trinity_gt

    trinity_gt Advanced Member

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    Are you sure that pump is compatible with the returnless fuel system on your car?

    Not all fuel pumps are happy being driven in the PWM-mode the FPDM produces...
  5. Bob Hughes

    Bob Hughes Member

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    I'm not sure if there is a way to test the frps switch or not. Personally, I know my car makes a steady 39-41 lbs from idle steady through the rpm range (pump actually produces 51lbs pressure under full boost to compensate at the rail). How old is the fuel pump?
  6. mikemora01

    mikemora01 New Member

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    sorry walbro 255 pump and a tuner in the area recommended the pump which was less than 6 months old. But you were right trinity_gt the pump was not happy at all, i replaced the pump today and the car runs better than it ever has. thanks for all the help guys!!
  7. mikemora01

    mikemora01 New Member

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    Bob what fuel pump are you running in your car because i just put my stock pump back in and am only getting 32 lbs at idle. I am unsure if the stock fuel pump will keep up with the cars fuel needs with stage 3 heads/cams/longtubes/injectors/etc... I just dont want to go back to the return style walbro because of the issues i had for months.
  8. Bob Hughes

    Bob Hughes Member

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    I have a fresh ford mustang gt pump with a boost a pump. Install a boost a pump. It takes about 20 minutes and you'll get (IIRC) 272lph on demand when you need it. Your fpdm will do all the thinking. Well worth the money especially if youre thinking of future upgrades. My last dyno run i was at 95% duty cycle making 455hp
  9. trinity_gt

    trinity_gt Advanced Member

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    32 at idle sounds about right.

    Remember, the system tries to maintain ~40psi across the fuel injectors. At idle there's a vacuum in the intake manifold and ports and so the fuel system reduces the absolute fuel pressure to maintain 40 across the injectors.

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