Mass Air Flow Sensor Mod / Air Fuel Ratio Adjustment

[ProtonXX]

As a experiment I partially blocked the hole to the inside of the sensor with tape. The idea was to trick the MAF sensor into reporting less air flow than it should & making the engine run more lean using less gas. At first I taped too much & the car was stalling. After re-adjusting the tape I was able to get the car to idle at a smooth 650 RPM & my scan gauge reported 40 MPG at 64 MPH.Has anyone tried adjusting the air fuel ratio before?

[Raven]

This sounds like a recipe for disaster. Leaning out the mixture too much will lead to an engine grenading. You will need to save a lot of money on gas to replace a blown engine. If I were you, I would remove the tape immediately before it's too late.

[goodvibe]

The system is a closed loop and will compesate somewhat for your mod. If it doesn't and you run too lean, you can overheat and destroy the CAT and cause your timimg to retard. The car already runs leanish at part throttle. It's why CAIs cause lean CELs when the get the mixture right at full throttle which is normally rich.

[ragingfish]

Sunny is right. You're asking for serious trouble. It would be in your best interest for you to undo that ASAP.

[trimovingxr]

like they said, not a good idea! if that mod really worked & it was safe for the engine, i would think that toyota would've already engineered that idea into the design. after all, toyota/pontiac would like to maximize fuel economy, too.for the scangauge to be reading that kind of fuel economy, you're engine must be running really lean. the only safe way to tune air/fuel (afr) is to adjust fuel injector duty-cycle with Camcon, eManage, Unichip, etc. and verify with wideband afr gauge.i will say, though, that toyota intentionally setup the fuel map on 1zz-fe engine to run conservatively-rich, in the upper rpm's, to protect engine from warranty disasters. using a Camcon, i have leaned-out the air fuel mixture a little (<2%) above 5000 rpm for lean-best-power using a PLX M-250 wibeband UEGO kit.