Do I need an Air Flow Meter?

[Pat Ford]

Previously, you (Diehl, Jeffrey) wrote:
{ Thanx for your reply.  I have a few more questions, though. <grin>
{ 
{ You mention that I would probably need a sensor for barometric  pressure,
{ air temp, and RPM.  The stock AirFlow Meter doesn't have any of this. 

the stock air flow meter does have an ambient air temp sensor, and it measures the air pressure drop in the manifold, by figuring out the airflow caused by it
 
{ 
{ I can see how one might argue that the difference between the engine vac and
{ the barametric pressure is what the AFM is measuring, so if this is correct,
{ I can see why I'd need the two pressure sensors.

altitude compensation for one, the baro pressure isn't fixed either

{ 
{ I can see where it would be NICE to know air temp, but my ECU doesn't seem
{ to use it.  In lue of that, couldn't I just rely on the Ox sensor to adjust
{ fuel correctly?

it does, just it mixes the signal check out the schematic

{ 
{ Would simply tying a potentiometer (sp?) to the throttle linkage be enough
{ to replace the AFM?

yeap IF the load is fixed and never varies that much

{ 
{ Otherwise, would I need a circuit much more complex than a MAF and an OPamp?
{ 
{ Thanx again,
{ Mike Diehl.
{ 


--
Pat Ford                           email: pford at qnx.com
QNX Software Systems, Ltd.           WWW: http://www.qnx.com
(613) 591-0931      (voice)         mail: 175 Terence Matthews          
(613) 591-3579      (fax)                 Kanata, Ontario, Canada K2M 1W8

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