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re:525i M20 engine 'stalling'



Eugene,

    Bingo, its your air flow meter.  Same behavior on all BMWs that used
the trap door style air flow meter.  The carbon band inside wears over
time from the copper button contacts on the swiveling arm wearing the
carbon down until its too thin to make contact in various places.  The
reason the cantankerous behavior clears up sometimes after shutting the
engine for some time is thermal expansion that leaves the pointer arm
stiffer and/or the band bent back flatter again.
    There is a procedure to bend the copper pointer arm, found under the
black plastic dust cap, back downward making it tighter against the
carbon band.  Also clean the contact buttons and band of carbon dust and
the less conductive glossy surface the band aquires over time.  this can
give you a fresh contact surface for many more miles.  Some argue you
should never in your right mind try to bend and retension the the AFM
pointer.  I did it successfully on many trap door afms with good
success.
    If you do not wish to try this procedure, then you will need to
replace your air flow meter.
Good Luck,
'jk

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