Quote:
Originally Posted by arghx7
Maybe @ mad_sb can post his logs and I can make some charts to explain a little further. You can go second-by-second and divide a cold start into different sections with different priorities for tuning: Cranking, run-up, idle speed flare, settling down, cat lightoff, gear shift, drive away.
That first few seconds of high idle is the most important for a stable start and idle. It's also the most important for cold start emissions. A lot of that exact behavior was put in there to meet a very specific emissions & fuel economy test cycle. For example, in the US Federal Test procedure, the driver begins in neutral and has to put the car in gear 15 seconds after cranking and then begin driving after 20 seconds. |
Sure, here is a log from this AM. Note that I am on high Ethanol content E85 (my test-tube style test kit shows E95) so my cranking pulse widths are way up there.
Also, see the attached pic of how my idle tables are set for this log and notice that the target idle rpm does not seem to pay attention to the target idle tables shown here during the retarded idle phase.. maybee it does try to adjust to hit the target.. hard to tell. Could be to do with the initial load and or airflow reference tables.. also shown..