1FastBrick

iTrader: (17)

My 06 truck does the Flex fuel conversion based on 02 sensor feedback the newer vehicles should be the same way.

Only the 01-02 L59 had the Fuel composition sensor in it.

JordanH

iTrader: (16)

I wouldn't think the O2 sensors would change the fuel tables and make the truck act like it was never tuned for five minutes after putting fuel in it?

JordanH

iTrader: (16)

I've gotta learn how to tune!

1FastBrick

iTrader: (17)

With Flex fuel settings enabled,

The 02 sensors themselves don't change it.

It uses the readings from the 02 sensor to adjust for the ethanol content. AKA a Virtual Flex-Fuel Sensor.

I believe it looks for a change in the fuel level before making adjustments.

This seems to be similar to what you are describing.

This document describes it better. Scroll down to the interference method about 1/2 way down and read about it. http://www.siucautomotive.com/presen...s/flexfuel.pdf

JordanH

iTrader: (16)

Gotcha! That sounds like the culprit! I'm gonna see if I can get ahold of the tuner and see if he messed with the flex fuel stuff, or disabled it...

1FastBrick

iTrader: (17)

Good deal!

Learning to tune your self would be very helpful.

JordanH

iTrader: (16)

Mitch over at TES emailed me back..... The flex fuel tables are still enabled! So that's the problem I'm having

GMCtrk

iTrader: (27)

Why would there be any effect if the fuel composition you are pumping in is the same as what's in the tank i.e. E10 gasoline?? If the o2 readings are stable there shouldn't be any changes in the fueling.

JordanH

iTrader: (16)

Read this article and it'll help explain. The computer recalculates things whenever it senses any rise in fuel.

E-85 Refueling Events - Hybrids, XFE, & Active Fuel Management - GM-Trucks.com

spike performance

lol glad u found the problem jordan lol