Huge Gas Milage Reduction from installation of intake

[Smokey159]

Originally Posted by YarisSedan

So my yaris sedan auto was geting about 36mpg adverage. Thats with no special driving techniques just driving normally. After installation of my weapon r intake. My mpg dropped to 29-30. I attribute this to the relocation of the maf sensor. Since how much the injectors spray is directly tied to maf readings.

The MAF sensor is relocated just a few inches away from the throttle plate and i think that even though the same amount of air may be going into the intake at the same throttle position witht he stock intake the location of the sensitive sensor may get a false reading of air when accelerating. Maybe even at a constant throttle position.

I checked this by hooking up my scanner to the computer and watching live data readings of the fuel trim. If you know a bit about cars fuel trim should always be close to zero with a little switching picked up by the oxygen sensors. My fuel trim is at about 20 percent for long term.

Which means the car is constantly dumping additional fuel leading to my reduction of fuel economy.

I am curiouse to see what happens to my fuel trim if i put my factory air box back but install a simply drop in K&N filter.

reset the ecu. Unplug the battery for a few minutes, hook it back up and let the car IDLE for about 5 minutes, then shut it off.

you should be good to go again.

[YarisSedan]

Originally Posted by Smokey159

reset the ecu. Unplug the battery for a few minutes, hook it back up and let the car IDLE for about 5 minutes, then shut it off.

you should be good to go again.

I tried that already and the fuel trim went back to rich. I forget which one its chrome tube with black filter. I think any filter which relocates the maf sensor to base of the throttle assembly would have the same effect. If you look at the factory filter the maf is farthest away from it right infront of the filter. Also the tube isnt perfectly smooth to help disrupt the flow slightly.

I know they do sell performance maf sensor that can read higher flows of air for heavily modded cars but should be unessisary for our cars.

[anonymous user]

I have the Blitz LM SUS intake. I noticed a decrease in FE, but after letting the ecu cycle after a few starts or so, it went back to normal. Staying away from increased high rev throttling and i've never had a problem since.
You have a good point though. Depending on how far the maf is away from your T.B. makes a large difference in A/F readings.