Lambda O2 sensor modification to increase air fuel ratio and run leaner.

[0brum60]

A digram of how the Lambda sensor works;

If we presume the engine is reading 0.45V being the stoichiometric value. In order to make the engine run leaner, the ECU needs to be fooled into thinking it's running too rich a higher voltage; a 0.1V increase to 0.55V for example. I'm unsure of the current or resistance of the sensor.

Would a voltage divider circuit be required to increase the voltage? Would this work? Thanks

 

[MacGyverS2000]

First look at the circuit required to read an O2 sensor... it's not as simple as you think.

Dan - Owner

http://www.Hi-TecDesigns.com

 

[pmrobert]

There are numerous types of lambda sensors. The diagram you've posted is of the more useless variety, the narrow band sensor. It's only reliable, reproducible ability is to tell you which side of stoich you're at. It is totally unreliable at telling you how far off stoich you're at. Most of the ECUs that use these as an input use them in the low load cruising operational area and merely vary the fueling so it swings back and forth over stoich so as to approximate an average stoichiometric operating regime. There are wideband sensors which are vastly more complicated and require some study to understand. Google may help with explaining O2 sensors but there are tons of grossly incorrect websites out there shilling ineffective products to the masses so beware. Academic sources are generally more reliable but aren't as exciting to read. YMMV.... As McGyver very correctly points out - it's not as simple as you think. Sensor manipulation was in vogue shortly after EFI became mainstream - it was the HHO of the 1980s and about as effective except it marked it's territory by means of brown-stained bumpers and CELs.

 

[LionelHutz]

You can often bump the switching voltage level a bit in the ECM.

 

[0brum60]

I think the lambda sensor in question is a EGO (at least for my project), ie not heated like a HEGO or UEGO. So I suppose you are right in saying that it'll have very little input in the feedback control loop.

Would you recommend MAP sensor manipulation?

 

[bradrs]

That is too open ended a question. In certain applications, it might make sense to tweak specific sensors. But in general, if you have a closed loop system, if you start tweaking the sensors, you are going to be fighting closed loop control. The O2 feedback will offset adjustments you make to the sensor inputs. You would be much better off to remap the ECM