Tricking your 02 sensor

[SVOboy]

Hmm, don't reccomend you do this, for emissions reasons, but I wanna get the idea out there.

<a href=http://better-mileage.com/memberadx.html target=_blank>O2 tricker</a>

In any case, the point it makes about water injection is a good one. If you really wanna take advantage of water injection for fuel economy you need to be able to control fuel injection (and timing), but I plan on doing that through my ecu, which is the uber safe way.

[JustMe]

Some people consider this to be the first and most important step to increase gas mileage. George Wiseman says "fuel injection systems are actually designed to prevent efficient combustion!" Read about the Electronic Fuel Injection Enhancer (EFIE) here:
http://www.eagle-research.com/fuelsav/efie.html

A low tech approach is to wrap the oxygen sensors in the exhaust pipe with several layers of aluminum foil to trick it into thinking the mix is too rich.

[DaX]

...or you could get an EMS and tune your engine then run in open loop all the time.

[diamondlarry]

I know of someone who does something like that. They unhooked the O2 sensor and came up with a way to dial in whatever longterm trim level they wanted. The only problem with the way it's done is you have to find a compromise that makes the car driveable for different driving conditions. His method was more or less a proof of concept type thing.

[SVOboy]

...or you could get an EMS and tune your engine then run in open loop all the time.

I'm with you! I posted this before I knew anything about engine management,

[Capcom]

I call this approach "The Poor Man's Chip-Tuning"

2-3 months ago i tried an electronic circuit to alter oxygen sensor's signals to provide fuel economy. And it worked providing %5 fuel economy at least!

Let me explain:
The circuit has an ON-OFF switch and a potentiometer and i installed it to the glass holder of my car and ran the wires to the engine bay. Device draws its electricity from the cigarette lighter in order to work.

I made 2 tests with both device is OFF and ON.
By using Cruise Control set to 110kmh/68mph I drove the same length road from point A to A on the highway, and did the same test when device is ON all the time. And also my car has a very accurate trip computer.

Test track was approximately 90km/56miles long and it's a 3x3 lanes road with both slopes going downhill and uphill.. by the way no traffic at all.

When going uphill unfortunately the device causes engine to stall very much and auto transmission shifts to upper gear and also causes engine to switch to "open loop" all the time.

If i made the tests switching ON the device only going downhill and level road and switching OFF during uphills i would guess it would make a more difference then %5.. maybe %10 or %20 or even more!

And unfortunately this device reduces the drivability and driving pleasure of the car when cruise control is not used and if also the car has an automatic transmission.

I tried to use it during city stop-go driving but it caused engine to stall so much and when i step on gas pedal more it caused engine to switch to open loop (which causes a sudden power increses unexpectedly) and also causes auto trans to downshift too early unexpectantly.

And i do not use it anymore which i also fear that this device causes engine to burn too lean fuel and i am afriad of causing permanent damage to pistons, rings, and valve heads because of high temperature.

By the way the device is still installed on my car's glass holder ready to be plugged in and switched ON.. i am very lazy

But i want to ask you a question:

How dangerous is lean burn ?
Does it really causes expensive damage to the combustion chamber elements ? or is it an urban myth ? And also i must mention that my car has a "knock control" mechanism. Does having "knock control" feature reduces the risks of lean burn ?

[diamondlarry]

I would first suggest that you use less voltage and try it that way first. Also, the fact that it is switching to open loop means that you won't be able to run the engine too lean. When the ECU goes inton open loop itm is running on a set of pre-programmed settings. If anything you may be running on the rich side in open loop. The pre-programmed settings are usually biased toward rich rather than lean.

[SIFLIGINIUS]

Hi!
I put my answer here because i think you know a lot about EFIE.

I built one with additional AFRD into but i need to compare results with anyone has built one.

Thankfully

Originally Posted by diamondlarry

I would first suggest that you use less voltage and try it that way first. Also, the fact that it is switching to open loop means that you won't be able to run the engine too lean. When the ECU goes inton open loop itm is running on a set of pre-programmed settings. If anything you may be running on the rich side in open loop. The pre-programmed settings are usually biased toward rich rather than lean.