Fuel pump

Discussion in 'Domestics' started by hidden1, May 31, 2017.

  1. hidden1

    hidden1 Jr. Member

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    Please fill out the following to ask a question.

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    DESCRIBE ISSUE....
    I have a 02 Dakota 3.9 quad ,automatic an when gas tank is 1/8 or less as I come to a slow stop it looses rpm an starts to stutter like no fuel.If I stop faster it doesn't happen.
    When I have 1/3 or more fuel in tank it idles fine at Any stops.
    Is this trash in pump?
    I'm getting 47 psi at port but drops to 30 after engine off.
     
  2. nickb2

    nickb2 Wrench. I help when I can

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    17 psi drop is not normal for this truck.

    I would suspect leaking injector in throttle body
    This comment is suspect, the fuel cell should not care if it is 1/3 full or not. Some is going on here that you are over looking


    But to help you along to easy this diagnosis, here is a troubleshoot you can try. Maybe a faulty check valve. check it out.
     

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  3. nickb2

    nickb2 Wrench. I help when I can

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    Trash fuel pump or not, the fuel pump on its own should never drop in 17 psi.

    So, heed above comment, something is being overlooked here.
     
    Last edited: May 31, 2017
  4. nickb2

    nickb2 Wrench. I help when I can

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    Post back, I will help further.
     
  5. nickb2

    nickb2 Wrench. I help when I can

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    Also try a code test with the key cycle, easy to do and may help.
     
  6. nickb2

    nickb2 Wrench. I help when I can

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    To do a key cycle is easy, just cycle the ignition key on off three times and observe. Normally, you should see a code appear in the digital/led display of the odometer. Post back which code you see, or if you just see a "done" message, then we will go further.
     
  7. billr

    billr wrench Staff Member

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    I'm wondering about the TCC, if it is unlocking properly. Live-data could quickly determine that.

    As to the key-off drop in FP, that may or may not be a problem. If the drop is because of a dribbling injector or external leak (spraying fuel out of a line), then it certainly is a problem. However, if the key-off drop is because of a check valve at the pump or an FPR that doesn't seat "bubble tight", then it is really of no consequence once the pump is running again.
     
  8. nickb2

    nickb2 Wrench. I help when I can

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    hmm, I didn't think about, but yeah, live data will mostly determine that.

    Thx for seconding my opinion, I think we should wait for op to go further.

    However, just for debate purposes, a FPR will never in my opinion cause a drop of this magnitude on a return-less system. Also, I have never seen a TCC give a fuel pressure drop in all my years.

    But hey, I learn something new every day.

    Btw, just for the other wrenches here, did you know they make work boots now with steel cable laces? Check them out. I just bought a pair, can't wait to see how long they will last. Never saw that concept before.

    The ones I bought are made by Terra and guarantied for life. Hard to beat. Check them out. ;)
     
  9. billr

    billr wrench Staff Member

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    This is return-less? I didn't think about that. There probably isn't any FPR at all...

    I'm not suggesting the TCC is causing an FP drop; just that the engine problem (stutter/stall) is because of the TCC, not a lack of fuel.

    An FP gauge, with a long hose, could tell a lot. Just see what the FP is doing as the engine struggles.
     
  10. nickb2

    nickb2 Wrench. I help when I can

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    Yeah, @Bill, the FPR is actually in the filter, hence a return-less system. Filter and FPR are all in the tank. Maybe this will help me to explain to the op that he is looking at the wrong place.
    Screenshot (63).png
     
  11. nickb2

    nickb2 Wrench. I help when I can

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    I know my english sucks sometimes, but the proof is in the screenshots.

    But, with the help of BAT auto, my english is getting better.:):bat:
     
  12. nickb2

    nickb2 Wrench. I help when I can

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    However, since I worked for a dodge dealer for a while, the whole unit needs to be replaced, unless they sell them on e-bay. Up north here. never have seen that.
     
  13. nickb2

    nickb2 Wrench. I help when I can

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    Maybe the op said he bought a toasted FP without realizing it is all an integral unit. Most often, when guy's replace the unit, a vent valve or gas line gets busted, which could account for the loss of pressure.
     
  14. nickb2

    nickb2 Wrench. I help when I can

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    ok nuff said about this, I will wait for the op to respond.

    it is 12 43 pm, I am just about to crack a heineken.

    so cheers
     
  15. hidden1

    hidden1 Jr. Member

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    No codes at all.in fact I have a odb2 /elm program on phone that shows a normal fuel trim reading too..
    I did correct s emissions Nldp recently but it has cleared fully after so many runcycles.
     

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