[Armin]

Assist and Lean-Burn at the same time? Yes! You can have your cake and eat it, too

I had noticed this phenomenon earlier, but it was extremely rare. What happened is this: While traveling in lean-burn at or above 70mpg, I push the accelerator very gently, to get the most power lean-burn will offer. Normally, at some point the engine will drop into rich burn and assist will kick in at the same time. But, very rarely as I said, assist came on before the car dropped into rich. That way I could maintain speed on shallow inclines and still get 70mpg! I posted on the yahoo group then, but nobody else had ever seen this.

Now, since I have the new ECM after the last recall, this appears to happen a lot more frequently! Oh joy! I still cannot fully reproduce it and I don't know what conditions allow this to happen. Sometimes, the car will even return to lean-burn, after dropping into rich, while assist is still on!

I don't know if it really is connected to the new ECM, but if it is, others should see it, too.

Anybody?

 

[ron]

I may have witnessed this last summer a couple times, buit I'm not sure. It's hard to tell when you're in lean burn mode - I usually set my speed constant and preferably diving on a relatively flat stretch of road, then ease up on the gas pedal and watch the instant mpg reading. It usually will drop off a bit. (I usually have it in L/100km) Now what you're saying is that if I re-apply some pressure on the gas pedal the assist should light up... I will have to look for this but it does sound too good to be true.

It's sure worth trying if you're after all the mpg you can get!

Ron

 

[Tim Maddux]

I have seen this, too, but in 3rd. On the way to work on a slight uphill I can sometimes trigger a few ASST bars with a light touch on the accelerator so that I'm still getting >75 mpg instantaneously. Like you say, it doesn't happen often enough to figure out.

 

[Armin]

mpg v. l/100km

It's hard to tell when you're in lean burn mode <...> (I usually have it in L/100km)

Ron,

as much as I prefer the metric system myself, using the l/100km mode makes it harder to see it you are in lean burn or not or to notice any small changes in mpg. On the low end, the l/100km scale has a much lower resolution. Only when it shows exactly zero, does it have an advantage over the mpg scale, which maxes out at 150 mpg.

Are you using cruise control? I don't think you'll ever see the lean-burn-assist effect with that. You have to push the accelerator very carefully and it's unlikely the cruise would do that. Unless you get this extremely gentle incline...

 

[Mike Dabrowski 2000]

I have noticed that the assist with lean burn can be invoked at will under the following conditions.
While climbing a moderate hill, at speeds less than 68MPH, in 4th gear. I press down on the gas till I have started to accelerate or maintain speed, using assist. I then slowley let up on the gas, the mpg will climb to 55-60 mpg, and the assist will stay on with 3-6 bars of assist for the rest of the hill climb. Once over the hill, the assist will drop out, and then the gas can be feathered fully for the down side of the hill.

Mike

 

[ncnightowl]

I have noticed that the assist with lean burn can be invoked at will under the following conditions.
While climbing a moderate hill, at speeds less than 68MPH, in 4th gear. I press down on the gas till I have started to accelerate or maintain speed, using assist. I then slowley let up on the gas, the mpg will climb to 55-60 mpg, and the assist will stay on with 3-6 bars of assist for the rest of the hill climb. Once over the hill, the assist will drop out, and then the gas can be feathered fully for the down side of the hill.

Mike

I have a 2000 5-speed. I get identical behavior in mine. Not sure this is lean-burn, however. It usually comes on at 75mpg or higher on instant mpg meter.