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Need a second opinion on diagnosis

Discussion in 'LR4' started by Tbh1981, Sep 26, 2020.

  1. Tbh1981

    Tbh1981 Member

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    Hello Roverites,

    A couple days ago I posted about DTCs related to low fuel pressure (P008A, P064C and P025D iirc). The truck had no other symptoms of low fuel pressure, just the check engine MIL and the DTCs I scanned. The next day the MIL was off, and and truck continues to run normally.

    Here's where I need a second opinion:

    Occasionally, at low speeds when I get on the throttle (such as pulling away from a stop, especially around a corner, or climbing hills off road) I hear a vibration from the front passenger side, behind the dash, or in the passenger footwell. To me it sounded like a loose piece of trim or something vibrating somewhere, but now I'm wondering if the HP fuel pumps could be making the noise.

    I haven't been able to record the noise because it's intermittent: happening when the engine is warm or cold, and not every time I accelerate slowly. I'll try to record the sound and post it here in an update.

    For now, has anyone seen any videos on YouTube or anywhere that demonstrates the sound of wonky HP fuel pumps on a 3.0 SCV6? If so, I could compare the noises and get a better idea of what I'm hearing.

    Gracias.
     
  2. SkyTree

    SkyTree Supporting Member Supporting Member

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    Would love to help, but I only really know the 5.0L V8, which is a different animal in it's engine and fuel system.

    One guess though... when you hear the noise, is your AC or Cabin outside air vent On or Off?


    SkyTree
     
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  3. Tbh1981

    Tbh1981 Member

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    The noise happens with all cabin HVAC systems off. The vehicle can be in any drive mode or gear range. I'm posting a video of the noise now.
     
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  4. Tbh1981

    Tbh1981 Member

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    Update:

    Here is a link to a Youtube video of the noise. This video is a few instances of the noise edited together, all from a drive I took this evening. The instances of the noise in the video are quite short, but I've heard this noise continue for up to 2 or 3 seconds, always when I'm on throttle (engine under load). When I get off the throttle, the noise stops.

     
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  5. jlglr4

    jlglr4 Well-Known Member

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    Pretty sure that’s the transmission heat shield bracket. The bracket cracks and allows the heat shield to vibrate a bit under load. Does it right around 1200 RPMs under load (you can probably brake toque it to 1200 and hear it). My 2016 LR4 had the same problem - fixed under warranty so I can’t tell you the cost, but I can’t imagine it’s a big deal to fix. There is a TSB on the issue. It’s annoying and the sound might get worse, but no other harm that I’m aware of if you can ignore it.
     
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  6. jlglr4

    jlglr4 Well-Known Member

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    Also, on your fuel pressure issue, I think there was a TSB on a fuel pump code that was eventually traced back to a software upgrade on the ECM. I had that problem show up once, then it went away and never came back. But I don’t think the code was the same as yours - actually your codes don’t look like the land rover specific codes. I’m guessing you are using a generic scanner. The GAP IID tool is a good investment.
     
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  7. SkyTree

    SkyTree Supporting Member Supporting Member

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    Had a listen to it, and while I certainly hope it isn't this, nor am I saying it is for sure this, but that sounds like your Transfer Case is grinding teeth.

    A good test of this theory would be to find a small, gentle downhill section or just get the vehicle up to some level of highway speed on a non-busy road, and put it in Neutral while rolling. While in Neutral step on the gas a few times and see if the noise occurs.

    If it still happens while in Neutral, good news, it's not something in your drivetrain, but if it only happens while you're in gear, then to my ear it sounds like your Transfer Case or drivetrain related.

    Would love to hear if it still occurs in Neutral or not, and hope this helps some.

    SkyTree

    Sent from my SM-G975U using Tapatalk
     
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  8. jlglr4

    jlglr4 Well-Known Member

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    Testing in neutral won’t rule out the transmission heat shield bracket. It will only vibrate like this under light load while in gear - like mild acceleration on take off. It will not usually make the noise in neutral. But, if you get the same noise under a brake torque with no rotation of the wheel, I believe that would rule out the transfer case.

    The heat shield bracket is a known issue on the 2016’s, and sounds exactly like the linked video. I’d put money on it.
     
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  9. Tbh1981

    Tbh1981 Member

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    Awesome replies folks.

    Sky tree - I'll take it out tomorrow and try to replicate the noise in neutral. It doesn't feel drivetrain related - there's no vibration that I can feel anywhere, and no slippage on power, but I'll take your suggestion seriously.

    Jlglr4 - thanks for the tip on the GAP IID tool. I was using my regular scanner. The LR4 is new to me and I'm still collecting tools for it.
    Your suggestion for the cause if the noise seems logical. It comes on around 1200 rpm, and goes away after a gear change, or if I come off the throttle. I'll crawl under there tomorrow and poke around under the skid plate.
     
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  10. jlglr4

    jlglr4 Well-Known Member

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    The heat shield probably won’t feel loose. The bracket attaches to the transmission in several spots, only one of the points might be cracked but not totally disconnected. If you hit it with a mallet a few times to get it vibrating, you might hear a hum. Really, just need to pull the heat shield and look at the bracket for cracks. The TSB has some illustration of the procedure and the part number for a new bracket: https://static.nhtsa.gov/odi/tsbs/2018/MC-10145634-9999.pdf
     
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