Thomas G. Stephens, GM's vice president and group director of engineering, GM Truck Group, says, "E85 is a viable alternative to gasoline where it is available. It is a renewable fuel that can be produced from grain or agricultural waste, and that makes it very attractive."
Stephens says GM's engineers re-designed the trucks' fuel systems with more robust materials to accommodate ethanol. They also optimized engine systems such as air-fuel ratio control and spark advance for every blend of fuel up to 85 percent ethanol, and added a fuel composition sensor that detects the percentage of ethanol present and relays that information to the vehicle's powertrain control module.
"The key to the success of GM's flexible fuel system was to make sure it is transparent to the user," Stephens says. "Our customers have come to expect the best from GM's full-size trucks, so we have to assure them that drivability will not be compromised, even in cold weather."
GM's flex-fuel trucks offer the same guaranty as its gasoline-powered models and the E85 system will be offered to customers at no extra charge.