Issue-again...CEL P062A and limp mode

Discussion in 'Dodge Charger SRT Hellcat' started by gilgamesh, Apr 7, 2016.

  1. gilgamesh

    gilgamesh Silver Member

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    Hey all,

    So I had my new build on the dyno and first pull BRRRRRuuuuuuuu.....she fell on her face....next pull...same thing.....
    Power was through the floor and A/F was off the charts high.

    I get her off the dyno and drive her down the street...everything was fine except crazy high IATs. Ahe drive completely normal...I get on the gas and BBBBrrrrruuuuuuuuuu...same thing...the car was having none of it.

    I have been getting the CEL code P062A consistently....

    Thoughts?
     
  2. Hemi Rocket

    Hemi Rocket Gold Member

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    Sounds like a fuel pump issue which is consistent with how the car is acting.
     
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  3. Hemi Rocket

    Hemi Rocket Gold Member

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  4. gilgamesh

    gilgamesh Silver Member

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    Any chance it is related to the fuel rail TSP?

    I can get on board with the obvious fuel system connection...but to me, how do the super high IATs connect? My engine temps are fine...just IATs are wayyyy high.

    In the past I have typically observed an average of 30deg above ambient. 25 if I am just cruising down the interstate, 35 around town if I am just chilling out. Now I am seeing 45-60 north of ambient. Sometimes more.

    Now, when I even get in the throttle just a little bit, the IATs DROP, almost like spinning the blower cools them off....

    Any chance that the blower air is just being rerouted around right now due to the bad fuel pressure?
     
    Last edited: Apr 8, 2016
  5. Bossnova3

    Bossnova3 Silver Member

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    Having the same issue I've read that it might be the sensor on the rails. I'm having exactly the same symptoms highly IAT and CEL code
     
  6. gilgamesh

    gilgamesh Silver Member

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    Bogging under WOT as well?
     
  7. Bossnova3

    Bossnova3 Silver Member

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    Well I've been having an issue at WOT when it gets to around 126mph, I've been dataloging with HP tuners and noticed the drop on pressure. Just today the code started popping up constantly and the fuel pressure doesn't read higher than 35 at idle on the HP tuners didnt WOT it just in case but checked and rechecked all fuses and everything is normal the pump is brand new cause we changed it thinking that was the problem but now it all seems to had been the sensor on the rail. Calling dealer tomorrow to verify if they have it in stock
     
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  8. gilgamesh

    gilgamesh Silver Member

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    Gotcha. Keep us posted. Mine is pulling hard, so long as I stay below 50% throttle. After that, she falls on her face from lack of fuel. What is the sensor? I'll be happy to grab one and try it myself as well.
     
  9. Bossnova3

    Bossnova3 Silver Member

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    It's the sensor on the fuel rail "pressure sensor" the part #
    68262026AA it's part of the fuel rail recall
     
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  10. gilgamesh

    gilgamesh Silver Member

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    Awesome. Thanks.
     
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  11. gilgamesh

    gilgamesh Silver Member

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    Bossnova, are you stock?
     
  12. fnkychkn

    fnkychkn swollen member Gold Supporting Member

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    fuel rail pressure sensor shouldn't make it bog under heavy acceleration. sounds like starving for fuel.
     
  13. gilgamesh

    gilgamesh Silver Member

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    Sure. But what does the pressure sensor do? Is it possible that the sensor helps the computer regulate the demand for fuel? If the sensor is screwed, will the pump deliver the proper fuel demands?
     
  14. fnkychkn

    fnkychkn swollen member Gold Supporting Member

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    FPCM (fuel pump control module) operation.

    from FSM:
    When the Powertrain Control Module (PCM) receives a ‘Start’ or ‘Run’ signal from the ignition; It energizes the Fuel Pump relay which sends a continuous 12 volt supply to the Fuel Pump Control Module (FPCM). The PCM also sends a control signal directly to the FPCM which regulates the Pulse Width Modulated (PWM) signal that will be sent to the Fuel Pump Module. The PWM signal (duty cycle) will vary from 10-100% depending on the input of the Fuel Rail Pressure sensor and other engine demands. The PCM receives a PWM signal from the FPCM representing the state of all inputs and outputs of the FPCM. This is a Constant Pressure Fuel system which means any Delta Pressure test performed on the Fuel Pump would show a continuous pressure (regardless of the changes in PWM). If a pressure sensor fails or other failures are present; The duty cycle goes to Limp mode (100%) to maintain fuel pressure.

    from P062A dagnostics:
    When the Powertrain Control Module (PCM) receives a ‘Start’ or ‘Run’ signal, it energizes the Fuel Pump relay which sends a continuous 12 volt supply to the Fuel Pump Control Module (FPCM). The PCM also sends a Pulse Width Modulated (PWM) control signal directly to the FPCM which regulates the PWM voltage that will be sent to the Fuel Pump Module. The PWM will vary from 10-100% depending on the input of the Fuel Rail Pressure Sensor and other engine demands. The PCM receives a PWM signal from the FPCM representing the state of all inputs and outputs of the FPCM. This is a Constant Pressure Fuel system which means any pressure test performed on the Fuel Pump would show a continuous pressure (regardless of the changes in PWM). If a pressure sensor fails or other failures are present; The duty cycle goes to a default setting (80%) to maintain fuel pressure.


    although they show conflicting default pressure settings, the theory of operation is the same.
    assuming no mechanical faults, the only way i can see the fuel pump delivering lower than specified pressure (58 +/- 5 psi) would be if the pressure sensor reported higher than actual pressure. i believe the delta between actual and reported pressure would be limited by PCM programming and, if this limit was exceeded, the PCM would log a plausibility fault, disregard the sensor and command default control pressure to the FPCM.
    if default pressure is 100%, i can't see the sensor causing a bog. if however, the default is 80%, i suppose it would be possible. would need to monitor fuel pressure using a mechanical guage to verify pressure sensor accuracy.
     
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  15. gilgamesh

    gilgamesh Silver Member

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    That is very helpful, thanks. I also found out that our cats have 2 pumps. A primary, used for regular driving, and a scondary, used under hard throttle.
     

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