Zero throttle fuel usage?
02-10-2009, 09:34 PM
#22
Senior Member
Join Date: 11-27-2007
Location: Austin, Texas
Posts: 1,115
Well, so far nobody has given the correct answer. 
Most of the newer engines today have what is called DFCO (Deceleration Fuel CutOff). When certain operating parameters are met, fuel is cut to the injectors. It helps with both mileage and emissions.
When the engine approaches idle, fuel resumes to prevent stalling.
I see it all the time with my wideband O2 sensor and during tuning data logs.
Whether manual or automatic, putting it into neutral will circumvent DCFO. So, for mileage, you are better off just leaving it in gear.
Hope that helps.
EDIT... Well pitbull answered right while I was typing.
Most of the newer engines today have what is called DFCO (Deceleration Fuel CutOff). When certain operating parameters are met, fuel is cut to the injectors. It helps with both mileage and emissions.
When the engine approaches idle, fuel resumes to prevent stalling.
I see it all the time with my wideband O2 sensor and during tuning data logs.
Whether manual or automatic, putting it into neutral will circumvent DCFO. So, for mileage, you are better off just leaving it in gear.
Hope that helps.
EDIT... Well pitbull answered right while I was typing.
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