Reprogram to Flex fuel?

[tahoe]

How can I reprogram my 04 5.3 Tahoe to the flex fuel program that use the virtual fuel sensor strategy?
I know it was implemented in the 06 models, old body style.
Is it a different ECU on my 06, making a reprograming of my 04 ECU impossible?

//

[EC_Tune]

The 02-06 Tahoes that were flex fuel use an actual sensor. You would need the sensor, wiring, and the segment swap for flex fuel on your 04. It can be done.

The 07's and later use the virtual sensor. It's in the operating system on the 07+ trucks & suvs to figure out the ethanol content.

[tahoe]

With all du respect, I beg to differ.
Is it possible to do the reprograming I wonder, since there IS a virtual fuel sensor implemented in My 2006?

I had a look in a L59 06 tune, and in the stock tune no faults are reported regarding the Fuel Composition Sensor, (since it´s not there), on a 04 L59 there are activeDTCs for the FCS.


My source for info.
http://media.gm.com/us/powertrain/en...M7_L33_L59.pdf
It says:
"2006 model year summary
• Close-coupled catalytic converter system
• Virtual fuel sensor for E85 flexible fuel (L59)"

And goes on:
"Virtual fuel sensor for E85 flexible fuel (L59)
Light duty GM trucks equipped with the flexible fuel-capable L59 version of the Vortec 5300 use a new virtual fuel sensor, replacing their previous physical fuel sensor, for improved quality, reliability and dependability and increased customer value.
Essentially, control for the fuel sensor has up-integrated into the Powertrain Control Module (PCM). Based on input readings primarily from the O² (oxygen) sensor, fuel level sensor and vehicle speed sensors and using a new algorithm, the PCM adjusts the length of time the fuel injectors are open (duration) to adjust fuel control in accordance with the different compositions of the fuel being used. "

//

[tahoe]

Anyone?

[Dozer]

So are some 04 5.3 tahoes flex fuel ready and some not having different PCMs for each?

[EC_Tune]

Dozer - Correct on the 04's. Some have E85 and some don't. The key is the L59 Flex fuel engine designation: 8th VIN = Z.

Tahoe - Good find. I did not know that GM implemented the "virtual" sensor on the 06 model year. I thought it was strictly on the 07 NBS trucks.
Looks like the 06's *can* be compatible with E85. However the way to tell is that the 0 Kpa line of the IFR table starts at 35 lbs/hr instead of 24 on a non-flex engine. I'm sure there have to be switch settings or something to enable flex fuel on the 06's and 07 OBS trucks. Got to look into this one...

You could swap in the 06 OS but you have to change the TAC & APP pedal in the truck as well to make it work. Then you get a sluggish throttle in the process. One other member went the other way to speed up his throttle body. Went from 06 to 04 OS, TAC & APP Pedal.

[tahoe]

What is "TAC & APP Pedal"?


//

[Dozer]

Also under Fuel Control~General~Air Fuel Ratio~Stoich AFR is scaled from 14:1 to 9:1 as the % of Alcohol is detected. I just noticed it on a 06 Hummer tune I was working on.

[Rhino]

So are some 04 5.3 tahoes flex fuel ready and some not having different PCMs for each?

My '03 Avalanche (non flex fuel) appears to have everything needed for E85 in the OS/tune. Unfortunately I'm missing the $500 Alky sensor and wiring harness.

[tahoe]

Unfortunately I'm missing the $500 Alky sensor and wiring harness.

As do I, that´s the reason for my question.
If it is as simple as do a "write entire" with a L59 My06 file, we have true flex fuel capabillity.

So, is this possible?

[Dozer]

So the algorithms from O2 sensors, fuel level sensor and speed sensor are used to tell the pcm its running flex fuel.. Would different O2 sensors and fuel level sensor be required such as the ones on the L59 vehicles or are they the same?

[Rhino]

As do I, that´s the reason for my question.
If it is as simple as do a "write entire" with a L59 My06 file, we have true flex fuel capabillity.

So, is this possible?

As EC_Tune stated, you would have to do the electronic pedal swap, although it should be feasible. I'm simply waiting to find a flex fuel truck in a salvage yard and pull the sensor from it.

[tahoe]

you would have to do the electronic pedal swap

Why would I need to swap the electronic pedal?
I am asuming you are refering to the pedal sensor?

//

[tahoe]

Any body who knows?

//