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09-10-2004 08:26 AM #1
09-12-2004 01:09 PM #2
Re: Can the blow off valve spoof the AFM?
If you are using the blow off valve to control the maximum pressure during exceleration, then yes you are venting metered air and therefore the ecm will be adding too much fuel.
My understanding is the pop-off valve is to vent high pressure when the throttle is controled. You chould use a waste gate to control the upper pressure of a turbo system.
09-12-2004 02:10 PM #3
09-12-2004 04:28 PM #4
09-15-2004 04:11 PM #5
09-16-2004 10:49 AM #6
Re: Sort Of...
In THEORY you should have an overly rich condition with a BOV, but the PCM strategy should prevent this from happening in any significant way. Typical strategy is to cut off the fuel injectors on throttle lift until the RPM's drop to some point (~1500 RPM). This is done for emissions and efficiency purposes. This strategy over-rides the AFM input which is essentially ignored during this brief period. Conveniently, this is when the BOV is venting, so the lost metered air doesn't matter.
Since the BOV wasn't part of the factory calibration, I won't suggest that what I've stated above works perfectly under all conditions. It is possible that the BOV is still open when the AFM input gets proxied again, but at least the time period when it's blowing off the biggest volume of air is ignored.
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