THE FLYING DUCHMAN wrote:
Quote:
Riding in Closed Loop allows the ECM to reset the AFV and compensate for the environment. It is good practice to do this periodically. Normal riding conditions will normally include Closed Loop riding for long enough. To ensure the AFV is about right for your setup, try and do a few miles on flat roads between 40 – 70mph and low throttle openings, with a steady throttle. This should set the AFV
If you have the time, you could try riding at 2000rpm for a couple of miles and check the AFV. Next try 2500rpm and check, then 3000 and 3500. This would validate your map in this region of Throttle / RPM combination, but is a lot of effort!
Remember with a narrowband O2 sensor (standard one) the readings are very slow to respond, hence the steady riding required to adjust the AFV.
Yes I have the prog and read this but it makes no mention of the open loop situation or what it does.
The ECM uses a narrow band sensor. This is only accurate at 14.7:1 AFR. A NB sensor acts as a switch and was designed for mixture control to work with catalytic converters.
For max power, you need approximately 10% richer than this, so control by the NB lambda sensor will never give you this (although it will know if the engine is running lean), hence an Open Loop mode where more fuel than a 14.7:1 AFR is possible.
In addition, the Open Loop mode is used when you shut the throttle off, where you want to be running leaner than 14.7:1 cos you want more engine braking...
The AFV is the icing on the cake for corrections applied to the Open Loop area.
I did some simple diagrams of the ECM logic here:
http://www.ukbeg.com/archive/modules.ph ... ic&t=32173