Deceleration Fuel Cut off
07-21-2008, 10:28 PM
#3
Platinum Member
Join Date: 05-09-2006
Location: "Upland" Mesa, Arizona
Posts: 6,805
Without thinking this out entirely....
Wouldn't the engine stall if the fuel injectors stopped the fuel from injecting....nothing to combust.
Seems to me, if you were decelerating by removing your foot from the gas pedal while going down a long hill, for instance, the engine would stall...no steering, no brakes...
Wouldn't the engine stall if the fuel injectors stopped the fuel from injecting....nothing to combust.
Seems to me, if you were decelerating by removing your foot from the gas pedal while going down a long hill, for instance, the engine would stall...no steering, no brakes...
07-22-2008, 08:06 AM
#8
Senior Member
Join Date: 10-02-2005
Location: VA
Posts: 1,245
DCFO does cut fuel to the injectors, on both auto and manual trans. There are a bunch of parameters and tables that control how it works. The only differences between the auto and manual calibrations are related to speed in gear due to ratio differences. Otherwise the same.
In a vary basic sense, it will work above certain speeds and RPMs. It will disable below certain thresholds and that is why the engine won't stall.
In a vary basic sense, it will work above certain speeds and RPMs. It will disable below certain thresholds and that is why the engine won't stall.
07-22-2008, 09:03 AM
#9
Founding Member
Join Date: 11-23-2007
Location: Texas
Posts: 8,210
Are we talking about HHRs here? Fuel never cuts off when the engine is running and if it does the engine stops running, so there is a problem. Only a hybrid shuts off all fuel injectors and vehicles with "Active Fuel Management", such as Tahoes and Suburbans, cutoff 4 of the 8 cylinders at times.