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Discussion in 'Range Rover' started by tomcat59alan, Apr 15, 2019.

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  1. Grrrrrr

    Grrrrrr Jedwood Spannerhands

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    Do I detect a yellow streak here?
     
  2. Mark Piercy

    Mark Piercy Well-Known Member

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    ooh, I thought I'd cleaned it up:eek:
     
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  3. RangeRoller dt

    RangeRoller dt Well-Known Member

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    They always do this. Just let it be, itl
    happen again in 6months but they always x and make up. The only thing I can do to make it worse is shout ‘viscous’ ! :eek::D

    Is the ‘co-efficient’ mentioned the IAT nominal value that it has for MAF?
     
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  4. Datatek

    Datatek Well-Known Member

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    There really are diesels with electronically controlled butterfly valves.
    There are also diesels fitted with EGR but no MAF.
    I learnt early on the the M51 will run happily with the MAF unplugged, no fault is logged according to Faultmate Extreme MSV-2, the only detectable difference is a slight increase in fuel consumption logged over several tankfuls.
    Later with my project car I learnt that if the pipe is missing from the MAP sensor it has no negative effect and again does not log a fault, the pipe must have been missing a long time as the pipe connection spigot was broken off the sensor. Before I knew this it did a 700Km round trip cruising at the speed limit. ( Electrical disconnection does throw a fault) Later while fixing the busted brake pipe on my daily driver I found the MAP pipe had split at the manifold end and dropped off. No idea how long it had been like that but there was no effect on performance or fuel consumption, I log every brim to brim.
    I'm always happy to learn, perhaps you could enlighten me as to why the MAF and MAP work that way?
     
    Last edited: May 23, 2019
  5. wammers

    wammers STILL BREATHING. Donater

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    Yes i know there are. Running with MAF unplugged gives an airflow fault on Nanocom. It must be pretty obvious to anyone with any knowledge that if the MAF is unplugged there is no air temp reading being received by the ECU so it uses a preset substitute value. That will effect consumption slightly as opposed to a connected working MAF. With the MAP sensor pipe disconnected there has to be a dip in performance as the ECU is not receiving manifold pressure information. Substitute values will be used but there has to be a dip in efficiency. A duff MAF sending implausible signals to the ECU can cause all manner of problems, Eg, EGR operating at the wrong time Etc. It is said in RAVE if you look closely and also in BMW service bulletins. It is stated in BMW bulletins that whilst the MAF sensor has nothing to do with fuelling, a malfunctioning one can cause the ECU to become confused. Butterfly valves are an attempt to reduce airflow into the engine to reduce Nox production. But the engine is not throttled by them. Diesels are throttled by fuel alone.
     
  6. Datatek

    Datatek Well-Known Member

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    So now you have found out that some modern diesels do indeed have butterfly valves. Like EGR, used to reduce excess combustion air when appropriate and in conjunction with SCR and ADDBLUE reduce Nox emissions.
     
  7. wammers

    wammers STILL BREATHING. Donater

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    No know that, it is you who have just found it out. Early euro 1 Transits had a throttle valve linked to the mechanical injection pump throttle cable. It's not exactly a new concept.
     
    Last edited: May 25, 2019
  8. Datatek

    Datatek Well-Known Member

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    Judging by your post #118 you were unaware of their use on modern diesels.
     
  9. wammers

    wammers STILL BREATHING. Donater

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    Now look here Keith i have forgotten more about diesel engines than you will ever know. I do not need to trawl the internet to gather information as you do. We are discussing a P38 fitted with a M51 BMW engine fitted with EU EC level II, EGR with feedback control. Level 3, 4 or 5 EC do not enter into the discussion. They use finer emission control and are progressively more complex systems. Diesel engines no matter how modern still work on the same principal that they did when Rudolf Diesel first put coal dust in a cylinder, compressed the air in the cylinder with a piston and got it to compression ignite. The more coal dust the bigger the bang, still albeit with a different fuel the same principal today, no matter how new the engine is. Other than air temperature which the ECU needs to know together with fuel temp to fine adjust fuel, if fuel is cold (dense) a slightly different amount will be injected for the same result than if it was warm. And to gauge accurate airflow for EGR purposes which is the feedback part of EU EC level II regulations. The airflow through a MAF sensor on ANY diesel engine has nothing at all to do with fuelling. Now if you want to know more than some of the crap on the internet, spouted by people who don't have a bloody clue what they are talking about. Do a five year apprenticeship and go to college and work on them for over fifty years as i have. This ridiculous diatribe is now over.
     
    Last edited: May 25, 2019
  10. RangeRoller dt

    RangeRoller dt Well-Known Member

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  11. Datatek

    Datatek Well-Known Member

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    Try telling some of that stuff about the MAF to Ricardo Engineering.
     
  12. wammers

    wammers STILL BREATHING. Donater

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    Oh for Christ sake go away. The M51 P38 diesel engine IS NOT fuelled subject to air flow through the MAF sensor. And neither is any other diesel engine.
     
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