map sensor and poor mpg

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Feb 10, 2008 | 07:16 PM

wendal

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map sensor and poor mpg

can the map sensor cause poor mpg. I my 5.4 is very bad on fuel. 04 250 cc 4x4
Are these engines hard on fuel when idleing.
thanks

Feb 11, 2008 | 06:48 PM

LxMan1

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From: Louisville,Ky.

It doesn't use a map sensor that I know of. It has a MAF sensor. These usually cause lean conditions and a check engine light when causing a problem. Most gas engines are very inefficient when idling.

Feb 12, 2008 | 01:47 PM

tim.moman

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Yes the MAF will read higher air flow as it gets dirty. Or gets oil on it from an oil type air filter it will also read high. This higher air flow reading results in adding more fuel and less timing. Which of course drops MPG. There are cleaners available for the MAF at auto parts stores which may help.

Feb 12, 2008 | 03:45 PM

LxMan1

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Actually, it is just the opposite, when dirty, they do note sense as much air this lean out the mixture. The MAF calculates how much voltage that it takes to keep the filiment at a certain temp. The more airflow, the more voltage to keep it up to temp. When dirty, it is insulated and does not cool as fast, causing a lower voltage and less fuel.

Feb 12, 2008 | 10:17 PM

wendal

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What do you use to clean it? Where is it located?
I was at NAPA today and they said to use carburator cleaner or brake cleaner. What do you think?
thanks for the help

Feb 12, 2008 | 11:33 PM

tim.moman

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do not use the cleaner you listed or you will be buying a new MAF. There is a MAF cleaner specifically for it on the shelf. In this case the counter person does not know and is steering you down the wrong path.

LXman
Makes sense and I would agree, but for some reason I hear as I noted. Now it may be related to oiled filters and oil getting on the sensor. Since I don't know I will just say cleaning is good

Feb 13, 2008 | 11:48 AM

LxMan1

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I have always used brake parts cleaner and have had no problems. It doesn't leave a residue like regular carb cleaner can. Oily residue equals insulation and less temp drop on the filament.