Hi AlexK -?I assume it's something that goes in series with the O2 sensor.?
The output of the O2 sensor is a very small voltage , and its not easy to accurately change it.
Other sensors , for example inlet air temp and water temp provide a varying resistance output to the computer.
These are much easier to alter.
Most of these wonder modules just (as said in a previous post) contain a resistor or 2 , and its true they a rew only a few cents in cost to buy.
But that ebay seller said this ?We noticed that each car from the manfacturer had the ECU settings that make the cars to run rich from the factory.?
Yeah RIIITE ,, most cars would be either prety spot on or a touch lean.
?We have developed vehicle specific Modules that make your engine run at complete optimum performance allowing the Air/Fuel Ratio to be automatically adjusted to the most fine tuned setting.?
Is he saying that he has spent more time on the dyno with exhaust gas anylizers than the factory did , and has improved on the results ?
--and also . perhaps he doesnt know that the computer automatically adjusts the mixture as you drive anyway.
Thats why you have O2 sensors.
?A car that runs too lean may cause engine and detonation problems, this is why the car manufacturers are creating vehicles making them run too rich for their own good.?
If the engine is pre-igniting because of the excessively lean mixture the knock sensor will pick it up and adjust ignition setting to protect the engine.
It is rare to see a standard car damaged by this now days.
Most likely his ?module? is causing a lean condition across the whole fuel map , which will improve FE a little , but in places where you have yearly car inspections and emissions tests it will likely fail.
If you were to email this ebayer ide guess he hasnt a dyno or a exhaust gas anylizer.- but I doubt he would admit it.
I suppose if you tweek the O2 sensor feedback you can lean out the mixture a tad but that may or may not affect the emmissions - depends upon the accuracy of the O2 sensor and the ECU if it was running the lowest emmissions or in need of a slight adjustment. Doesn't explain where the "more power" comes from though. Legal could just mean that there is no law against it - doesn't make it legal just not illegal.
(I'm not an expert on this stuff by any stretch of the imagination, I am only repeating stuff I have read up on. Please correct me if I am wrong ! ! )
I don't think you can get these kicked off ebay, they are there by the hundreds. They're like weeds.
I think the gimmick works, but I can't say what the long term effect on the engine will be. It's just a resistor that replaces your IAT sensor. I went for the gimmick too, just to see what it was. I always go for the cheapest version of a scam, so it "only" cost me about $6 total. It was just a resistor and some instructions. Therefore, I paid somebody $6 for a 25 cent resistor. The fancier ones are packaged in cute little boxes or can snap directory onto the IAT sensor connection (less mickey mouse).
For performance, the resistor is chosen to tell the CPU that the IAT is colder, leading to more fuel being injected (rich fuel/air mixture), aka super cheapo Cold-Air-Intake. For fuel savings, the resistor is chosen to tell the CPU that the IAT is hotter (lean fuel/air mixture). The only "skill" involved here is picking the right resistor for the right car. In both cases, you may be short circuiting your emissions (that's why I never installed mine).
To me the following would be a safer (and more complicated) way to implement the gimmick :
1 - Get a ScanGuage (the mechano-bio-feedback device for any GasSaver).
2 - Install a potentionmeter setup in place of the IAT sensor (I don't know how to do this, you need an electrical GasSaver guru for this). The potentiometer will allow you to select whatever IAT temperature you want the car's CPU to "see". In the car, it will just be a dial that you spin like a volume control to pick whatever temperature you want.
3 - Install a separate "IAT" sensor (let's call it IAT2 for this discussion) for yourself at the same location as the car's IAT sensor. This way, you can know what the real Input Air Temperature is at any time.
With this setup you can know the following :
A - The ScanGauge will tell you what the potentiometer is telling the CPU.
B - The IAT2 will tell you what the real outside air temperature is.
With this setup you can decide whether or not to emulate the IAT2 outside air temperature or to "shadow" it. That is, you can be adjusting the potentiometer to a temperature that is maybe 40 degrees F hotter than the IAT2 reading. Conversely, if you don't like how the car is driving, you can emulate the outside air temperature. I think that the rate of change of the outside air isn't too great that you can't fiddle with it and still drive safely.
I think that the *real* thing to do is piggy-back the potentiometer with the real IAT sensor in order to bias the IAT sensor into always reporting +X degrees F, but I don't know how to do that.