Engine shut off while downshifting

[katflap]

Originally Posted by 2LZ

All good stuff katflap and probably right on, especially when it comes to the "canned mapping" from Delphi.

Question though, since this is a closed loop system after it reaches operating temp, (open loop or choke mode should run on a set mapping), wouldn't then the O2 sensor (along with MAP, etc..) take over and adjust the injector pulse width, as needed, to attempt to reach it's optimum 14.7 to 1 or as close as possible?.....or I wonder if by EPA standards, as you suggest, don't allow that anymore and run them lean, even in closed loop?...which really makes no sense because usually a lean condition creates more HC's. I've never figured that one out. I know way back when I was a CA smog tech, anytime we saw high HC's, they had an air leak somewhere.

It would be interesting if someone could get a sniff at full operating temp at both idle and cruise rpms.

Until the engine reaches a pre defined operating temperature and the 02 sensor is up to a working temp your bike is in open loop.

In open loop it uses all the other sensors to reference against the map tables in order to try and maintain a 14.6:1 air/ fuel ratio when idling, gentle acceleration or cruising.

Without the O2 sensor in use it has no way of checking that this has been achieved.

Once the engine temp is around 25 degs C and the O2 sensor is up to temp your bike enters in to closed loop.

In closed loop the O2 sensor is been used as well. Now the bike can monitor the emissions and now knows if the air fuel ratio is correct and will make small adjustments many times a second to maintain 14.6:1 A/F .

Your bike will only remain in "true" closed loop when idling, gentle acceleration and cruising.

At any other time a different fuel/air ratio is required. There are a number of "overrides" that can come in to play when this occurs to give a richer or leaner mixture.

I didn't know that a lean mixture gives high HC's , that doesn't make sense to me but I have no knowledge about this

here is a graph of my RX3 showing a zero injector pulse when the throttle position hits zero

And the next graph is of my engine temp before I changed the thermostat. the temp only peeks at the end because I came to a stop and let it idle. (temp in degs C )