[Supras] AFM cleaning

[berniek at technicaldevelop.com]

Roberto:


    Sorry, I thought you had done a conversion to a GM hot wire meter in 
my former response.  Apparently you have not. 


    The stock AFM black stem on the electronics module creates a vortex, 
whose frequency varies with airflow, much like the cause of ripples in a 
waving flag.  There are two small holes through which the varying 
pressure from the vortex enters and twists a metallized Mylar strip back 
and forth, reflecting LED light onto a phototransistor at the same 
frequency.  The signal is amplified and sent to the ECU.  I believe the 
full scale frequency is 4 KHz at fuel cut.


    I've read of instances where they have been cleaned of oil from 
things like HKS air filter elements with contact cleaning spray shot 
into the holes, then being shaken out and allowed to dry.  Some reports 
stated the method to work, others said the opposite.  It could be a good 
test to make sure first that the cleaner will wash away oil without 
harming Mylar (polyester).  I do know that Acetone, MEK, Toluene and 
Xylene attack it.  Any of the alcohols will not.  A longer chain alcohol 
like isopropyl will probably be the best alcohol for removing oil. 


    Bernie