2011 LR4 - MPG getting worst

Discussion in 'LR4' started by djkaosone, Aug 8, 2017.

  1. stufrowin

    stufrowin Full Access Member

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    Long time debate - will never be answered to all satisfaction

    Some say including dealers that the oil from the filter will dislodge and clog/fowl sensors, K&N obviously states that is not the case and is safe. I use them and I am in the middle, sure if you put way too much oil on it obviously not good. Another concern complaint is if it allows more air flow than it must allow more particles into intake.

    Again I don't think they are valid concerns but this is just my experience. You'll get differing opinions from the experts as well.

    Honestly I haven't noticed power change with the LR4, but I haven't done dyno or any other objective data monitoring.
     
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  2. ktm525

    ktm525 Full Access Member

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    Perhaps you are getting some awful build up in the intake tract and on the back side of the intake valves? The 5.0L is an early DI design and eventually will suffer from the lack of fuel washing the back side of the valves. You may need a de-carbonizing of the intake side?
     
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  3. djkaosone

    djkaosone Member

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    Just got back from my Vegas trip and on the way there I got 11.8 mpg going uphill and against the wind. Coming back downhill and with the wind I got 13.2 mpg. Not too happy with the outcome, but it was slight improvement from before.

    @jhartz - Before I forget, THANK YOU. You're giving me great suggestions.

    I'm running Goodyear Duratrac 255/55/19 on 06' OEM Range Rover wheels (adventurous weekends) or 265/35/22 Nexan Roadian HP 102V XL on Marcellino Kensington 22" (city or classy days), no brakes dragging (EBC green stuff pads and rotors checked), I changed out the plugs last 6k with new NGK Iridiums ILKR6C-10 and decided to switch to Denso 3444 Long Life Iridiums (way better than the NGKs) and torqued to specs 15 lb-ft (from what I remembered), and I feather the gas where the pedal never reaches half way down the floor.

    For the tires, yes the Duratracs are off road knobby tires, but the diameter is slightly bigger and does really well on-road too. The Roadian tires are pure street tires and is about 0.7" diameter smaller than the Duratracs. With that said, I actually get slightly better mpg with the Duratracs when I first got them on (I ran the same mpg test over 3 fill-ups). Back then it didn't really matter which set of wheels/tires I had on, I got over 16 mpg. Something degraded somewhere and I need to look for it.

    I'll check the plugs again, and torque them down to specs.

    The fuel trims are in these ranges after 3 point in time captures with Terrafirma iCarsoft i930:

    STFT - Bank 1 -1.6% to -4.7%
    LTFT - Bank 1 -6.3%
    STFT - Bank 2 -0.8% to -4.7%
    LTFT - Bank 2 -6.3%


    @stufrowin - I'll try spraying CRC valve cleaner into the TB a shot.
     
  4. ktm525

    ktm525 Full Access Member

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    Curious why do you say that? I am at 90k miles or the original plugs and looking to do them next spring. As a reference on my last trip (1500 k kms) I was averaging about 18 MPG at an average speed of about 80 MPH.


    Also have you de carbonized the intake valves?
     
  5. djkaosone

    djkaosone Member

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    @ktm525 - Due to my history of NGK and Denso running them on various cars in the past from import tuning (down to 2 degrees colder in turbo cars) to daily driven cars. I've found that NGK Laser Iridiums are great plugs compared to a lot of plugs out there, but the Denso Long Life Iridiums is better. It has a smoother drive throughout the power ranges in all gears, it has slightly better spark, and lasts a LOT longer. I typically run through NGK plugs every 2 years during the import tuning scene, but doubled that with Densos.

    Changing the plugs on the LR4 is difficult compared to my '02 Lexus IS300, and my IS300 requires me to pull off the engine cover, intake, throttle body, spark plug wires, and ignition coils just to get to the plugs. But I can replace all 6 plugs within 30 minutes. The LR4 has very little space to work with and my first time around it took 3 hours, I got it down to 1.5 hours if lucky. So to me, I replaced the NGKs with Densos when I had to recheck the torque settings the first time. My truck now is about 92k and don't have to change it for another 100k? J/K.

    Overall, take my words with a grain of salt. It's really a personal preference, especially when it's difficult it is to replace the 8 plugs.

    I have not decarbonized the intake valves, to be honest I'm still debating if I want to CRC the intake valves. Worried if I do I might potentially introduce sealing issues where the valve(s) won't seal properly and now I have a new can of worms. On the opposite side, it'll probably burn off the gunk on the valves and finally run better.
     
  6. djkaosone

    djkaosone Member

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    @stufrowin - I just read your post on what you mentioned on here. I'm going to give it a shot tonight and clean it out with the CRC you mentioned.
     
  7. roverman

    roverman Full Access Member

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    Not sure if it was mentioned, but have you tried a 'real' fuel injector cleaning? One where they hook you up to a machine rather than just pouring a can of something in? The tank additives are nice, but more for 'keep clean' maintenance than for really cleaning things up. Sorry for your troubles, 13 hwy is awful!
     
  8. Bogwhoppit

    Bogwhoppit New Member

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    I'll chime in here.
    K&N are shite. Hold them to a light and holes everywhere. Anyone who says they do better at filtering than paper is on crack. The fine oily cotton hairs do make it onto the MAF. From my own personal experience of running them on my old M3 track car. I ended up using the foam filters which Prodrive Subies use. K&N are lying about this as far as I'm concerned.
    Anyway, there is nothing wrong with the breathing capacity of the 5.0 V8 in these vehicles. There are shag-all restrictions.

    I know a fleet manager (2 million vehicle miles p/yr) that switched over to K&N for all of his vehicles to save money. Within a year he had gone back to paper, due to excessive wear and faults. Problems corrected.

    Check the function of the electronic park brake, and make sure its not dragging if all the other simple stuff is ok.

    Are you using 91 Octane? If I'm feeling cheap and run 89, my mileage drops approx. 2mpg Try filling up at another station, as they may be farting around Octanes or it's old gas.
     
    Last edited: Aug 16, 2017 at 8:36 AM
  9. jhartz

    jhartz Member

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    I think the Denso Iridiums are a great plug: ran them in my last Jag; cheaper too. Google long term fuel trims; although right and left bank are balanced (a really good thing), -6.3 leads me to believe you have dirty injectors or dirty MAF sensor.

    But I think it's the tires.
     
    Last edited: Aug 16, 2017 at 10:37 AM
  10. OL Trekker

    OL Trekker Member

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    Get a gallon of Marvell Mystery Oil from Amazon - put 1 qt in the engine oil at next oil change- put about 4oz in every tank fill for three tank fulls and in every third tank full thereafter - and behold the improvements. Other 'fuel system cleaners' cannot hold a candle to MMO. Look it up. And get rid of the K&N air filter -they don't filter all that well, do more harm than good IMHO (check the micron efficiency against a standard paper filter) and you don't drive hard enough for the engine to 'need an improved volume of air flow' (all just sales BS). Tire type/pattern can have a HUGE effect on mileage too. I run Cooper ATP's on 18's which cause a drop of around 2 mpg compared to road tires on 20's. But a MUCH better combination than road patterns/sizes for off road.
     

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