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Thread: New MAF restricted performance

  1. #11
    Senior Member MikeAlford's Avatar
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    Thanks for the post Frank, No that's fine, replaced with new one when I got the car, as you quite rightly point out they crack.

    I swapped the original MAF back in and everything returned to normal.

    It demonstrates that you need to get the genuine part and although the jacket is the same, clearly the electronics inside the MAF sensor are different in some way. I'll clean the old one and see where we go from that. I have recorded the fuel trims so I know what's normal next time.

    Forgive me for not replying sooner, Just getting over burst pipe in kitchen! Just what you need for Xmas!
    2003 XK8 Coupe 4.2 V8 - Oh, to have a V8 back - Joy!
    1972,1981,1991 XJ6 4.2L
    1966 S type
    1965 Dailmer 2.5L V8 Warick Grey
    1962 MK II 2.5 manual with overdrive (faster than the MK VII 3.4)
    1957 MK VII 3.4 Manual

  2. #12
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    I wouldn't describe the electronics as "profiled for a particlar application"

    its more that the uit is sized according to the maximum expected airflow.

    There will be a unit for 100g/sec airflow which will give 5v output at 100g/sec
    Then there will be a unit for 500g/sec, which will gove 5v output at 500g/sec
    etc.

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  4. #13
    Senior Member MikeAlford's Avatar
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    Ah,right I understand so they are profiled for flow rates of different engines.. Yes that makes sense, thank you Woody!.
    So from your earlier comment, the flow rate for XKR is different to XK8?
    And is that in the resistance of the wire, or the electronic circuit (if there is one) inside the plastic jacket?
    Last edited by MikeAlford; 02-12-19 at 09:30. Reason: addional infor
    2003 XK8 Coupe 4.2 V8 - Oh, to have a V8 back - Joy!
    1972,1981,1991 XJ6 4.2L
    1966 S type
    1965 Dailmer 2.5L V8 Warick Grey
    1962 MK II 2.5 manual with overdrive (faster than the MK VII 3.4)
    1957 MK VII 3.4 Manual

  5. #14
    Senior Member frankc's Avatar
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    Quote Originally Posted by MikeAlford View Post
    Thanks for the post Frank, No that's fine, replaced with new one when I got the car, as you quite rightly point out they crack.

    I swapped the original MAF back in and everything returned to normal.

    It demonstrates that you need to get the genuine part and although the jacket is the same, clearly the electronics inside the MAF sensor are different in some way. I'll clean the old one and see where we go from that. I have recorded the fuel trims so I know what's normal next time.

    Forgive me for not replying sooner, Just getting over burst pipe in kitchen! Just what you need for Xmas!
    Hope you sent the old one back as "not fit for purpose"? Your entitled to it by law, even off Ebay.
    2003 Zircon Blue XKR Convertible.
    It's in the detail.
    [SIZE=4]

    For a list of most topics written in this 'Story' Please click here.

    Cannot see any photos? PHOTOBUCKET FIX please CLICK HERE FOR SOLUTION

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  7. #15
    Senior Member MikeAlford's Avatar
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    Yes Frank I know you're right, not fit for purpose, but sometimes I just like to cut it up and see what's inside.

    did that on my XJ6, the old straight six circa 1981, I cut the top of what was then the sensor in those days, (big bulky thing), found there was an adjusting screw, put a gas analyser on the exhaust and tuned the engine. Brilliant the car had never run so well.... so just might cut the top off and see what we have inside!


    Money isn't the issue with me, it's about understanding how things work; bugs me when I don't know what goes on. If there is a black box, then I need to open it, and in this case I've nothing to lose.

    Now where's that junior hacksaw.....
    2003 XK8 Coupe 4.2 V8 - Oh, to have a V8 back - Joy!
    1972,1981,1991 XJ6 4.2L
    1966 S type
    1965 Dailmer 2.5L V8 Warick Grey
    1962 MK II 2.5 manual with overdrive (faster than the MK VII 3.4)
    1957 MK VII 3.4 Manual

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  9. #16
    Senior Member frankc's Avatar
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    Quote Originally Posted by MikeAlford View Post
    Yes Frank I know you're right, not fit for purpose, but sometimes I just like to cut it up and see what's inside.

    did that on my XJ6, the old straight six circa 1981, I cut the top of what was then the sensor in those days, (big bulky thing), found there was an adjusting screw, put a gas analyser on the exhaust and tuned the engine. Brilliant the car had never run so well.... so just might cut the top off and see what we have inside!


    Money isn't the issue with me, it's about understanding how things work; bugs me when I don't know what goes on. If there is a black box, then I need to open it, and in this case I've nothing to lose.

    Now where's that junior hacksaw.....
    Ohhh the old junior hacksaw. Still have mine from the 60's.

    When you have opened it up you will have to post some pics for us to see.
    2003 Zircon Blue XKR Convertible.
    It's in the detail.
    [SIZE=4]

    For a list of most topics written in this 'Story' Please click here.

    Cannot see any photos? PHOTOBUCKET FIX please CLICK HERE FOR SOLUTION

  10. #17
    Senior Member MikeAlford's Avatar
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    Well Frank here's a link to what's inside.

    https://drive.google.com/file/d/16k6...ew?usp=sharing

    I cut the top off, and it's well glued in very impressed. No adjustment though, shame, but if I transfer the circuit from the original one to the new chinese version, then that might work, only problem is that I might burn my bridges so to speak.
    Attached Thumbnails Attached Thumbnails MAF.jpg  
    2003 XK8 Coupe 4.2 V8 - Oh, to have a V8 back - Joy!
    1972,1981,1991 XJ6 4.2L
    1966 S type
    1965 Dailmer 2.5L V8 Warick Grey
    1962 MK II 2.5 manual with overdrive (faster than the MK VII 3.4)
    1957 MK VII 3.4 Manual

  11. #18
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    Quote Originally Posted by MikeAlford View Post
    Ah,right I understand so they are profiled for flow rates of different engines.. Yes that makes sense, thank you Woody!.
    So from your earlier comment, the flow rate for XKR is different to XK8?
    And is that in the resistance of the wire, or the electronic circuit (if there is one) inside the plastic jacket?
    Yes, the flow rate for the supercharged car will be +25% or so

    The unit is quite simple - it puts out voltage from 0V to 5V in direct linear relationship to how much air is going through.

    What is actually does is to heat an element and to measure both the temperature it gets to and how much current is used in keeping it at that temperature. Ergo, for more airflow, more current is required to keep the element hot.

    Max airflow will be 5V output for both. There will not be any adjustment, there will be some very simple software in the pic in the unit

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