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MAF and MAP Standard Readings 2013 150 Prado 1 KDFTV Black Smoke

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  • MAF and MAP Standard Readings 2013 150 Prado 1 KDFTV Black Smoke

    Hi all

    I have recently noticed my exhaust becoming excessively black, to the point that even low load on flat road not much more than idle it leaves a haze behind.

    When giving it a boot load it bellows with black smoke, and even when steadily increasing the throttle when stationary and giving it a gently rev it blows quite black.

    The vehicle is otherwise well maintained, has ~160km on the clock, injectors are ~20k and 14 months old, air filter is fresh, manifold should be clean as it was cleaned completely after I added a catch can.

    The engine also idles fine, and seems to run fine apart from a very intermittent low boost condition that goes away on restart which I believe is unrelated.

    I performed some diagnostics today to try and assess the health of the MAF sensor, idea was to determine if the MAF readings increased in a linear fashion at 250rpm increments - and they do.

    What I did discover though were a few peculiarities in the figures which I was hoping could start some discussion.

    From a cold start the MAF reading at idle (802rpm cold engine) was 9.1 g/sec up to around 55 degrees coolant temp. I also noted that the MAP was 78kpa (ambient was 101kpa).

    Then whilst the engine warmed up I noticed an audible change, hard to describe but like it was lower pitched. At the same time the MAF reading at idle (now 700rpm) went to ~18 g/sec and steady.

    The at idle MAF did not change from there remaining between 16 and 18 g/sec.

    I thought this was a bit high, and I am struggling to find a good reference for expected normal MAF readings.

    What I did also notice was that the MAP (Manifold Pressure) was still low at ~80 kpa. So I shut the engine down to assess the MAP with no pressure, and it was still around 80 kpa. The Barometric Pressure readout was steady at 100 kpa and I am almost at sea level and the current actual atmospheric pressure is 101 kpa.

    By my logic I would assume with the engine off the MAP should be close to or equal to the Barometric Pressure. Am I correct in this thinking?

    For reference my MAF readings were, and when charted these are near linear:
    RPM MAF g/sec
    913 24
    1250 36
    1480 43
    1750 52
    2000 59
    2250 66
    2500 77


    So questions:
    • Could this cause the engine to run rich?
    • Does anyone have a reference MAF reading chart for the 1 KD FTV?
    • What is a normal MAF reading at idle

    Cheers
    Cam

  • #2
    Hello Cam, did you ever work out the reason for black smoke? Cheers.
    D4D. How long will it last?

    Comment


    • #3
      If you get onto the Toyota manuals you can pay $16.50 to access everything for 24 hours. There is a diagnostic description for black smoke. Sounds like you are on the right trail, black smoke is caused from running too rich. The first thing would be to check to make sure the injector codes were entered correctly, there are no loose connectors to any of the sensors and ensure no obstructions or leaks in the intake system.

      From there, the check for the MAP and MAF requires a warm engine (above 70C) and idling at 4000rpm with no load (i.e. neutral, no AC on etc.). Here, you'll want to see a MAF reading above 84 g/sec and a MAP of 114kPa or higher. The normal idling pressure should match the ambient pressure of around 94 to 104kPa depending on your elevation, so yours definitely is low and you are correct in your thinking. Are the sensors the same type? If so I wander if you can swap then around and see if the ambient one is then reading low and faulty? If you turn the car "ON" without engine running, then both pressure sensors should read the same.


      If that checks out (unlikely, so added for detail) you need to determine if the EGR system is blocked. You mention that the intake was cleaned however the EGR cooler itself could be blocked. If so, it's usually best such items as the EGR cooler and EGR valve are replaced, not cleaned (cleaning the cooler could cause cracks and leak coolant into the engine). Again, best to start here with a warm engine above 75C as the gas flows through the EGR cooler, under this and it is bypassed using the VSV. You can run some active tests to close and open the EGR valve which will then tell you if anything is blocked. with the EGR open around 55% you'll want to see 4.5 to 10.5 g/sec on the MAF and 13 to 20 g/sec when it closes at idle.After 15 minutes of idling the EGR valve shuts and stays off until you either restart the engine or drive around, which appears to explain your observations. So that all appears normal.

      After all that you move to checking the injector feedback and volume. There's some massively incorrect bro-science going around this forum on these values. Anything above +3.0mm/st is bad (even though you have new injectors one or more could have been clogged - they'll normally show up as +5.0mm/st). Anything below -3.0mm/st DOES NOT necessarily mean a flogged injector. It is normal for an injector to be below -3.0mm/st if one or more of the other injectors are positive. This is very well documented in the Toyota service manuals. Also, you can not diagnose the feedback values without the total injection volume. For instance, your feedback volumes can be all fantastic but they could all be flogged and worn injecting too much which is when they all need to be replaced.

      Comment


      • #4
        Originally posted by spencerm106 View Post
        If you get onto the Toyota manuals you can pay $16.50 to access everything for 24 hours. There is a diagnostic description for black smoke. Sounds like you are on the right trail, black smoke is caused from running too rich. The first thing would be to check to make sure the injector codes were entered correctly, there are no loose connectors to any of the sensors and ensure no obstructions or leaks in the intake system.

        From there, the check for the MAP and MAF requires a warm engine (above 70C) and idling at 4000rpm with no load (i.e. neutral, no AC on etc.). Here, you'll want to see a MAF reading above 84 g/sec and a MAP of 114kPa or higher. The normal idling pressure should match the ambient pressure of around 94 to 104kPa depending on your elevation, so yours definitely is low and you are correct in your thinking. Are the sensors the same type? If so I wander if you can swap then around and see if the ambient one is then reading low and faulty? If you turn the car "ON" without engine running, then both pressure sensors should read the same.


        If that checks out (unlikely, so added for detail) you need to determine if the EGR system is blocked. You mention that the intake was cleaned however the EGR cooler itself could be blocked. If so, it's usually best such items as the EGR cooler and EGR valve are replaced, not cleaned (cleaning the cooler could cause cracks and leak coolant into the engine). Again, best to start here with a warm engine above 75C as the gas flows through the EGR cooler, under this and it is bypassed using the VSV. You can run some active tests to close and open the EGR valve which will then tell you if anything is blocked. with the EGR open around 55% you'll want to see 4.5 to 10.5 g/sec on the MAF and 13 to 20 g/sec when it closes at idle.After 15 minutes of idling the EGR valve shuts and stays off until you either restart the engine or drive around, which appears to explain your observations. So that all appears normal.

        After all that you move to checking the injector feedback and volume. There's some massively incorrect bro-science going around this forum on these values. Anything above +3.0mm/st is bad (even though you have new injectors one or more could have been clogged - they'll normally show up as +5.0mm/st). Anything below -3.0mm/st DOES NOT necessarily mean a flogged injector. It is normal for an injector to be below -3.0mm/st if one or more of the other injectors are positive. This is very well documented in the Toyota service manuals. Also, you can not diagnose the feedback values without the total injection volume. For instance, your feedback volumes can be all fantastic but they could all be flogged and worn injecting too much which is when they all need to be replaced.
        Or you can PM me for free.....

        Comment


        • #5
          Do these readings have to be started with cold engine or can be done with a warm engine as well?
          D4D. How long will it last?

          Comment

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