Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
2012 Ram going into open loop when off the accelerator
Have a 2012 Ram 1500, 4.7l No trouble codes, hard on fuel. Both long and short fuel trims bouncing form -2 to +8 when driving down the road. Noted when completely off the accelerator, ALL fuel trims go to 0.0 and stay there when until I get back on the peddle. Checked Loop status and see that it goes to Open Loop when the fuel trims go to 0 Any ideas? Tks Buzzie
Hey buzzie,
The behavior you describe is quite normal.
It's known as decel fuel cut.
When you are decelerating, (off the gas), the PCM shuts off the fuel injectors. Obviously fuel trim is a useless tactic when the injectors are inactive, so if you happen to be watching loop status at the time of decel fuel cut, it will cycle into open loop.
Some manufacturers will call this open loop drive, or some other designation to let you know it's part of the strategy, but not always.
Paul talks about this during some of his classroom lectures.
Topic Author
