Can someone with a scan gauge test for lean burn

Cobb · 12-19-2011, 05:49 PM

I and a former engineer believe the i2 has lean burn. You may notice a failed attempt to enter ev mode when the car is fully warmed up leads to it using gas only, but still netting infinite mpg.

The xgauge code below was provided by Eli.

To get a secondary O2 sensor voltage readout on CANbus, it would be:

TXD: 07E00115
RXF: 044105150000
RXD: 2808
MTH: 000100020000

You could also try the AFR XGauge for CANbus:

TXD: 07DF0124
RXF: 044145240000
RXD: 2808
MTH: 05B900800000[

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jonnyvtec · 12-20-2011, 06:15 AM

Its unlikely without a NOx absorbtion catalyst.

Lean burn still uses fuel, infinite MPG is probably just a glitch much like the I1 has when it sometimes locks on 150mpg regardless of how your driving.

Zwolfe · 12-20-2011, 09:01 AM

I doubt it's a glitch. It's easy to replicate what Cobb is talking about.

Lean burn or not, I have no idea.

I thought it was cylinder deactivation. The sweet spot on my I2 for what Cobb is talking about is 47 MPH. Given a flat road, my I2 will read 100+ MPG all day long and the battery is NOT being used.

Cobb · 12-20-2011, 06:31 PM

I too believe its a mode vs a change in the delta v. If not lean burn maybe its randomly going to 2 vs all 4 cylinders for power? When I was at the body shop this year the guys commented that when the ac was off and it was idling it didnt sound like a car, but a sewing machine. When I last had my scan guage I do know the open vs close loop indicator was all over the place even after the car was warmed up. From what Ive seen online it appears the 2nd oxygen sensor goes off scale when its in lean burn and it uses rppms and another factor for guestimating the afr.

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Cobb · 12-29-2011, 03:13 PM

Well, neither program works.

I do see the car is in closed loop and fuel consumption goes to .3 or less.

When in ev mode it goes to open loop and fuel goes to 0.

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Willie Williford · 12-29-2011, 06:27 PM

When it goes into "open loop" it is using something other than the o2 sensor for fuel calibration........What I got no idea.
HTH
Willie

Cobb · 12-29-2011, 07:22 PM

Yeah its something like rpm x something else. for a preset afr for lean burn vs the normal ratio based on the oxygen sensor. I can assume that is really the only sure fire way currently to tell if it enters lean burn or EV mode when it goes to open loop.

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Willie Williford · 12-29-2011, 08:06 PM

Normally open loop will only happen at first warm up, full throttle, or de-acceleration.
HTH
Willie

Cobb · 12-29-2011, 08:49 PM

Full throttle?!?!?! Oh thats right, you got a turbo.

I try to limit my tps to no more than 30 on steep grades to maintain speed, I typically do not exceed 20 tps around the city.

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Cobb · 01-01-2012, 08:56 AM

Still need to try reprogramming the sc2, but in the mean time.....

I tried map and mpg to see what else is going on. Turns out mpg was all over the place. When the i2 was in ev mode with use of cruse control it read 37mpg and -2 for timing. When in ev by foot it reads no timing and 99999mpg.

When it would read 100% on the mid it said anywhere from 82-168mpg.

I do not quite understand the map reading if its from sea level or the reverse. What I do see is when the brakes are on its 14.5 As your mpg increases the number goes lower to zero. When the i2 is reading 100% like its in a possible lean burn the map is about 4. When it seems to exit this mode its at 7. The gph is .3

So looks like's just a delta V just a change in load vs engine efficiency.

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