A coworker wants to run E85 (sp?) in his 05 3/4 ton 6.0 gasser. GM only says you can run it in the 1/2 ton 6.0 but not the 3/4 ton. What gives here?

It has to be set up from the factory to run E85, part of the Flexable Fuel Vehicle package. I don't believe that they offer it in the 2500's. That could be the difference. 10% ethanol is the only blended fuel he should run on his 6L.

The 5300 comes in three versions, Flexible fuel, Vin has a Z in it as like the eigth character. The regular cast iron I think the vin code is a t, and the Alluminum block which is rated with a few extra ponies and has a b vin code.

If you run a high ethenol content in a non flex fuel setup, I believe it will run, but maybe not very well. I also think that in time the high alcohol content will eat away at the rubber seals and fuel lines. I know the flex fuel option has teflon lined fuel systems.

E85 Has No Lubrication Characteristics, So It Could Damage Any Thing Related To The Fuel System In An None Flex Fuel System. From The Fuel Pump, The Lines To The Ingectors.

the O2 sensor is different, along with program to feed injectors the required fuel, different scales and engine has to adapt to fuel, along with components in fuel system. E85 is 1.85 gal here wish could run wifes car on it, but not.

saw article on running E85 in none FFV, read truck(ford F150 w/5.4) was running 4-5 gl($10.00) E85 then filling with 87 oct at 1/4 tank no problems 3 yrs. have ethanol plant here and bumped in to worker(chevy 2000 with 5.3 non FFV) been doing same for 4 months, exact thing. engineer came to inspect plant and told could run upto 40% with no problems. so i am testing in sons truck, drove to store and went to get around a car and truck took-off like never before. from prior reading ethanol is close to gas 1.1-1.3 instead of methanol that starts at 1.6 with comp and timing optimized. guy with ford calculated E85 is equal to 105 oct mix with 87 oct work rough works to 92+/- oct, cost savings works to $8-10.00 per fill up instead of using 92-93 oct gas. new project other sons 78 chev, gonna replace hoses and adjust timing w/ MSD box to see how it works. E85 runs about 30cents below 87-89 here.