Going lean when returning to idle.

[[email protected]]

Stock displacement LS1
Stock Heads
228/232 .588/.595" 113lsa Cam

Car runs great except for one problem I can't seem to track down. When slowing to stop, as the car returns to idle it leans out very badly (18+ afr). It returns to stoich. after about 5 seconds of sitting at idle. The faster I stop the worse it leans out. I've tried turning DFCO off, but it had zero effect. My fuel pressure is a consistent 58-60psi.

Any ideas?

track4sep.hpt

[mowton]

how about a log of the scenario including the following PID's...MAF (g/sec), MAF Hz, Dynamic Airflow, throttle Follower, Throttle cracker, Fuel trim cell, LTIT (In gear and P/N), STIT, Idle desired Airflow, commanded AFR LTFT's, STFT's and wideband....


Ed M

[[email protected]]

I loaded the pids you suggested in the scanner and will scan my drive home. I will upload the scan tonight.

[[email protected]]

here is the scan. I hope I set the scanner up correctly

leanidle.hpl

[mowton]

Using the PID's you set up (looks good) and the .cfg you set up, start the car cold and just let it idle as it warms up. Turn off the fans via the VCM controls before you start. Don't touch This will collect the idle desired airflow per the engine Temp. Set up a histogram using Idle Desire Airflow as the data and in the Row & Col Axis select the table "idle Adapt Airflow Maximum vs. ECT. Set both units to F and close/save histo. After the log go to this histo and load data. This will be your new BRAF values. copy and paste and complete trend up and down temp range for cells you didnt collect. Also in adaptive idle airflow table set the max in gear /acoff to 1, Min In Gear/ACoff to -1.0 and AC Offset Min/In gear to -.5 prior to the idle scan.

Report back.

Ed M