[rice_classic]

Originally Posted by jshadeck

http://www.popularmechanics.com/_mob...l-fuel-economy

Coasting in gear uses 0 fuel. Coasting in neutral uses fuel same as idling.

DFCO=Deceleration Fuel cut off. Engine and Catalyst must be at operating temperature otherwise no DFCO.

DFCO (as my understanding) was part of the OBD1->OBD2 changeover so if your vehicle is newer than 1996 is should utilize DFCO in some form or another.


Here's an OBDII easy reader:
http://groups.engin.umd.umich.edu/vi...ganesan_w2.pdf

DecelerationEnleanmentand Idle Speed Control: When the driver decelerates the vehicle very hard, the PCM reduces the engine torque by cutting off fuel , withdecelfuel cut off mode in which the fuel injector is turned off or the duty cycle is drastically reduced.

Originally Posted by ravenblackfrs

if the car is RUNNING... its running because fuel is being sprayed into the compression chamber VIA the injectors

In this case, under DFCO, the momentum of the car via the wheels/drivetrain is running the engine.

Let's see, how would the Chief say it?
Uphill, engine run make car go.
Downhill, car go make engine run.

Well, it was funny in my head.