Mazda3- Drop in gas milage after I put in a new air filter

[JEDI]

2005 mazda3i

i used to get 29city/35hwy. now i get 26city/29hwy.

also, it now takes a couple of cranks to start the engine. b4, it used to start smoothly.

This is how i replaced the air filter:
i removed the screws and removed the air duct to the battery.
then i opened the air filter holder. but i could only open it part way. i had to use some force to open it enuf to barely get the old air filter out, and the new one in.
Then i put all the pieces back the same.

So any ideas?

THX

edit:
bought Puralator air filter ~$18

 

[JSFLY]

did u use the same type/brand/size air filter?

or did u put in one of those performance air filters?

 

[OS]

Originally posted by: JEDI
2005 mazda3i

i used to get 29city/35hwy. now i get 26city/29hwy.

also, it now takes a couple of cranks to start the engine. b4, it used to start smoothly.

This is how i replaced the air filter:
i removed the screws and removed the air duct to the battery.
then i opened the air filter holder. but i could only open it part way. i had to use some force to open it enuf to barely get the old air filter out, and the new one in.
Then i put all the pieces back the same.

So any ideas?

THX

edit:
bought Puralator air filter ~$18

Is the media/construction the same?

for my car the OE filters had alot more pleats and looks like it is made from oiled paper.

some store ones were made from a thicker fuzzy/cloth looking media with fewer pleats. I could actually feel a loss in throttle response.

 

[Heisenberg]

You didn't by chance damage the MAF sensor when you were changing the filter did you?

 

[JEDI]

Originally posted by: Heisenberg
You didn't by chance damage the MAF sensor when you were changing the filter did you?

MAF sensor? Where's that? and whats that???

 

[iamwiz82]

Where do you live? Winter gas is at the station now, so that would account for a 10% drop.

 

[Vette73]

Originally posted by: Heisenberg
You didn't by chance damage the MAF sensor when you were changing the filter did you?

Yea I was about to ask about that. Is the check engine light on?

Also did you get the filter housing and pipeing ALL back on. I have seen soem Corvettes and F-Bodys not have all their intake pipeing back on right after going to a lube station. You have to remove it ALL to get it back on. But in the name of doing it quick they just pull off part and pinch the intake hose and dirt gets past the filter.


So check all your wiring near there and reinstall the intake piping to make sure there are no leaks.

 

[BCYL]

There are a few reasons this can happen, most have been covered above, but i'll summerize here:
1) You put in a higher performance air filter, which is letting more air into the engine. Thus, the computer will put in more fuel to compensate for the additional air, using more fuel
2) You damaged the Airflow sensor when you changed the filter, and the computer is now getting incorrect readings on how much air is going into the engine, resulting in more fuel being put in
3) Your gas station already put in winter gas, which typically result in 10% lower milage

I would say the likelihood is 1 > 3 > 2

 

[Scouzer]

Originally posted by: BCYL
There are a few reasons this can happen, most have been covered above, but i'll summerize here:
1) You put in a higher performance air filter, which is letting more air into the engine. Thus, the computer will put in more fuel to compensate for the additional air, using more fuel
2) You damaged the Airflow sensor when you changed the filter, and the computer is now getting incorrect readings on how much air is going into the engine, resulting in more fuel being put in
3) Your gas station already put in winter gas, which typically result in 10% lower milage

I would say the likelihood is 1 > 3 > 2

Actually....a more efficient air filter will improve fuel economy.

And I mean efficient by airflow, not particle filtering.

 

[lyssword]

You put too many volts for teh cpu and ram

 

[Staples]

What is this winter gasoline that everyone is speaking of?

 

[thirdeye]

Originally posted by: Staples
What is this winter gasoline that everyone is speaking of?

Winter gas is pretty much all year gas any more.

 

[SZLiao214]

Originally posted by: thirdeye

Originally posted by: Staples
What is this winter gasoline that everyone is speaking of?

Winter gas is pretty much all year gas any more.

From what i was able to find on wiki, winter gas looks like normal gas with modified additives. They allow a car to start in colder weather. Maybe it helps the gas not free too.

 

[Vic]

Originally posted by: Staples
What is this winter gasoline that everyone is speaking of?

It's a mix with 10% ethanol. As ethanol contains less energy by volume than gasoline, it is common to see up to a 10% reduction in fuel mileage.

 

[JEDI]

winter blend gas

i dont remember having this problem last year w/the same car.

anyone have a pic of what a mas sensor is on the mazda3?

THX