using 14.047 for desired AFR and not 14.63?

[dc_justin]

FWIW - I wouldn't change stoich on a LS1 PCM based on supposed E10 ethanol content because the mixture can vary from gas station to gas station and even brand to brand. Here in MN, all gas is ethanol based (with a few rare exceptions), so it's a fact of life. Some of the newer stations have pretty good in-ground ethanol sensing equipment that allows them to monitor the content of each tank, but some don't. Most of the dealers also have ethanol content testing equipment to check fuel content when vehicles come in for warranty work for related repair. You would be surprised how much variance there is even from one station.

I've done a few test tunes with different stoich and fuel combos and always come back to the factory stoich and E10 93 octane for my TA for the best overall results. My .02

The constant being that there is always SOME ethanol, with an "ideal" ratio of E10, it would make more sense to set the tune to the correct E10 stoich ratio and let trimming take care of the 2-3% swings either way. The alternative has fuel trims consistently 4-7% higher than they would be based on airflow calculation inaccuracies alone.

[DrkPhx]

The constant being that there is always SOME ethanol, with an "ideal" ratio of E10, it would make more sense to set the tune to the correct E10 stoich ratio and let trimming take care of the 2-3% swings either way. The alternative has fuel trims consistently 4-7% higher than they would be based on airflow calculation inaccuracies alone.

That certainly makes sense and seems like the logical thing to do. However, my car does not like to idle at anything richer than 14.6 (optimum is 14.8-15.2) according to my WB. The same holds true for some part throttle driving condtions as well. Certainly not at 14.0, otherwise it would choke on itself and die at idle and chug at low speed driving. This is CL with a MAF (no flames please).

[CalEditor]

That certainly makes sense and seems like the logical thing to do. However, my car does not like to idle at anything richer than 14.6 (optimum is 14.8-15.2) according to my WB. The same holds true for some part throttle driving condtions as well. Certainly not at 14.0, otherwise it would choke on itself and die at idle and chug at low speed driving. This is CL with a MAF (no flames please).

Have you logged a wide-band on a flex fuel truck?

[CalEditor]

Has anyone logged a Wide-Band on a Flex Fuel?
Has anyone looked at the spark tables on a Flex Fuel?
Has anyone looked at the spark tables on a lean cruise?

[DrkPhx]

Have you logged a wide-band on a flex fuel truck?

No. I don't own a flex fuel truck. My points are specific to a LS1 PCM that does not have those enhanced capabilities to sense ethanol content and adjust accordingly. We're all here to learn, so please shed some light on the subject.

[CalEditor]

No. I don't own a flex fuel truck. My points are specific to a LS1 PCM that does not have those enhanced capabilities to sense ethanol content and adjust accordingly. We're all here to learn, so please shed some light on the subject.

Download the 2 bin files from 2005 5.3L Trucks with the same OSID's that I posted.
Compare the 2 Calibrations. One would use the Ethanol Sensor and the other doesn't.
Them tell me what the Wide-Band reads at idle or cruise with E10 on the Flex Fuel

[gmh308]

Has anyone logged a Wide-Band on a Flex Fuel?
Has anyone looked at the spark tables on a Flex Fuel?
Has anyone looked at the spark tables on a lean cruise?

Yes.

[CalEditor]

Yes.

What did you find to be the Wide-Band Reading on a Stock Calibration?

[gmh308]

What did you find to be the Wide-Band Reading on a Stock Calibration?

Lambda = 1.00.

[CalEditor]

Lambda = 1.00.

Well how does that work?
Are you saying E0 = 1.00 Lambda and E10 also = 1.00 Lambda

So the Scan Tool (Tech II in my case) will display 14.7 as the target AFR and the wide-band will read 1.00 Lambda on E0.
Then with E10 the Scan Tool will display 14.1 target AFR and the wide-band will read 1.00 Lambda?

I understand that 1.00 Lambda for E10 is 14.1 AFR. Hmm did I state that correctly