[brucepick]

Thanks, LeanBurninating.

Now for tonight's installment in the quest to understand the HX lean burn logic:

The switch to not allowing lean burn under 64/65 mph is determined by a distance clock. Yup. A simple counter that kicks in after about 23 miles or so (~37 km). Keying off the ignition for 10 seconds reset the counter, after which full lean burn was again available. Hopefully only a brief shutdown is needed; for this test I wanted to be sure to be over 10 sec. to try to ensure a full reboot.

As I watched for LB failure (that is, losing it below 65 mph) I paid close attention to engine and intake air temps and they were moderate. ECT was 182 deg. F which is where it always stabilizes unless it's over about 75-80 degrees outside, or if I'm running the cabin heat. Intake air was about 75 deg. which is about as moderate as you could get. Nothing else going on that I noted. Keying off the ignition and bump starting it brought it back to full lean burn operation - as long as I kept the throttle below about 30 tps, it would maintain LB down below 55 mph in 5th. After a restart it does require a mile or two of driving before LB will kick in, but I can deal with that.

So now I want to find how to wire an ignition cutout. My regular commute is about 60 miles so it would be nice to be able to maintain lean burn. Maybe the easiest is to find the power wire to the ECU circuit at the ign. switch and put an intermittent-off switch in that line, either before or after the ign. switch.