Basically, when I had little to do at work I worked on some theory and testing of o2 sensors. My aim was to fake a rich mixture to the ECU so it would trim leaner. Trim is what the correction to the fueling output is called.

So I had a play around with some voltage deviders, and a bunch of resistors but found that the voltage would polarise the o2 sensor and on start up cause it to read 2v for some period. This made the intergral component of the closed loop fuel control to slowly lean the mixture out until the motor struggled.

I set it up with basically the 3 legs of a pot going to o2 input o2 output and 5v, so depending on the resistance of the high resistance side, it would lift by a ratio.

Once the o2 sensor returned to a normal voltage, it worked, but only after 2 or 3 minutes of poor running.

Then using some op-amps and the same idea to raise the output by 0.0 to 0.5 v scalable by a pot.

I found that anything over a 440mV raise in output would cause the o2 the input to be shifted too much to cycle still, and the intergral band would take off. 430mV was a good offset, and allowed the mixtures to be effected between 0.2:1 and 0.4:1, as seen in the wideband graphs.

So in theory, it works, but to how much advantage and to what negative effects. My wideband tail sniffer doesn't fit in the exhausts completely enough to bolt up, so I can't do anything other than load up on the stall and free rev.

It should sneak me a few extra KM per tank, and I have had 3x 600km trips to average as a base line, so any results from now will have a solid bench mark.



Okay so I took some pictures of the setup/testing

This shows the input voltage and the adjustment voltage. Input was the 800mV, and the output was the input plus the adjustment (400mV).
http://adaptronic.com.au/jason/o2-trick/images/input%20and%20offset.jpg

This shows the input and the output voltage. It isn't exactly 400 because the durst is a much better meter than the fluke, and updates faster.
http://adaptronic.com.au/jason/o2-trick/images/input%20and%20output.jpg

Wideband installed (barely!)
http://adaptronic.com.au/jason/o2-trick/images/tail%20sniffer.jpg

http://adaptronic.com.au/jason/o2-trick/images/idle[1].jpg



Overall, you can see the leaner mixtures (ZOMG PROOF?!? not just feels smoother and changes gears nicer?) and I picked up a good 0.5L/100km fuel econemy which is pretty good considering it was more an experiment than something which was expected to work. Results were averaged over a few 600km trips, and at best I picked up 1.3L/100km. Oviously the conditions wernt identical but i sat on 100 and had AC on both times and kept everything consistant as possible.


Probably going to make them in a neat little box for some friends on AMC, also with my intercepter I am working on and testing on a 3.0 and 3.5 thanks to lucifer (i have 3.0 L)

http://adaptronic.com.au/jason/o2-trick/images/2000[1].jpg
http://adaptronic.com.au/jason/o2-trick/images/1500[1].jpg
http://adaptronic.com.au/jason/o2-trick/images/circuit.jpg
http://adaptronic.com.au/jason/o2-trick/images/circuit (2).jpg

Hmmmmm Interesting.

Firstly.

You have way too much time on your hands, and I mean way too much time. Does your boss know about this? LOL

Secondly - love the proof in A/F graphs - you my sir, are a king amongst men.

Thirdly - nice Fluke multimeter - if only I could afford one :redface:

Fourthly - let me know if you build these in future - somewhat interested :-)

Wow thats awesome stuff, would be interested if you were building actually. Would be good if you could have an adjustable one with a dial you can turn somewhere in the car? So then you could set it at factory settings, or go for economy or power.

Ollie

There is only about $15-20 dollars of components so they would only retail cheap so its possible I'll build them.

Power wise, you can't use this for power. This effects closed loop fuel control, which is the mode the ECU used when on cruise and light load. When the ECU wants the air fuel ratio to be 14.7:1, it will entre closed loop mode and activly change injector duty cycle to maintain 14.7:1. What I did is trick the ECU to thinking that 15.1:1 is 14.7:1 so it maintains a leaner cruise.

As soon as the ECU needs a richer air fuel ratio, it entres "open loop" mode where it just references the fuel map for pre tuned values for fuel and timing. Changing these requires a retune or aftermarket ecu if the computer is not editable.

Yes, I do have too much time but I try put it to good use :)

You wait for my MAF interceptor, its real trick.

Ers; Those flukes are base model stuff, my DURST next to it is worth 10x that!!!!! That DURST is a sweet meter.

There is only about $15-20 dollars of components so they would only retail cheap so its possible I'll build them.

Power wise, you can't use this for power. This effects closed loop fuel control, which is the mode the ECU used when on cruise and light load. When the ECU wants the air fuel ratio to be 14.7:1, it will entre closed loop mode and activly change injector duty cycle to maintain 14.7:1. What I did is trick the ECU to thinking that 15.1:1 is 14.7:1 so it maintains a leaner cruise.

As soon as the ECU needs a richer air fuel ratio, it entres "open loop" mode where it just references the fuel map for pre tuned values for fuel and timing. Changing these requires a retune or aftermarket ecu if the computer is not editable.

Yes, I do have too much time but I try put it to good use :)

You wait for my MAF interceptor, its real trick.

Ers; Those flukes are base model stuff, my DURST next to it is worth 10x that!!!!! That DURST is a sweet meter.
How much we talking for one of these meters :P

']How much we talking for one of these meters :P


About what your's and my magnas are worth, hahaha

Nah between $500-1000....

interesting bit of info there thanks. I recently changed my o2 sensor after having surging problems that were worse when cold, but constant under normal throttle(10.5)

This piece of electronic is very similar with Eagle Research's EFIE
http://www.eagle-research.com/store/index.php?main_page=product_info&cPath=2&products_id=16
It is being used in conjuction with Hydrogen Generator.

in theory using one of these EFIE would stop the ECU self adjusting (trimming) fuel when you use a SAFC (like myself).

the benefit of these EFIE would be to use a higher oxygen content fuel without it tricking the 02 sensor reading a higher 02 content in the exhaust and telling the ECU to add more fuel. Some of the EFIE's i have seen tell the ECU the car is at 14.7:1 at all times unless its over 14.7:1, in an attempt to save fuel and also save your engine if it gets to lean by letting the 02 sensor do its job of telling the ecu to richen up as its needed (when say over 15:1)

Hence why people use them on cars running HHO electrolizers, as without one in theory the car will use more fuel, if all systems are running properly

Let us all know how you go ROY.

Using my SAFC i have now seen an average (3months, 3 tanks a fortnight) increase in kms per tank of 26. Thats with the SAFC only and no tuning done above 2500rpm.

They use EFIE on HHO electrolyzer because the exhaust gas allegedly contains more oxygen thus making the mixture rich.

yeah im quite up to date with the whole HHO hybrid thing.

Just pointing out using one with a AFC such as the apexi, would stop the car trimming fuel, which is what is so hard to use the SAFC to get better fuel econ. The ecu constantly trims back to stoich.

Point in case i had -22% fuel trim on the apexi (going -2% at a time). It took till %22% before the ecu would stop trimming and adding the extra fuel to get the mixtures it wanted (could tell by the static/erratic idle and susequent missfires)

With an EFIE on it, it would just come out and there would be no trimming. Which is what ROY wants to do with his MAF enhancer i presume. For what i paid for my SAFC and installing it myself, i paid it off in 15 tanks of petrol (2 1/2months)

The EFIE gear does do basically the same, same as any programmable ECU with a definable cruise AFR or even a SAFC to some extent.

I didn't envent the idea, but I did do it for next to nothing just more so as something to keep my mind busy and for a bit of Magna development (although not actually magna specific) and also to create constructive TECHNICAL discussion on the boards I frequent.

From my recient trip to port douglas, I managed 7.4L/100KM over 900km. That was about 150km of city/sight seeing and 750km highway. I suspect that with a new o2 sensor and my mod, that would be the best highway fuel econ seen by a 3rd gen, and I had the AC because of rain and 34 degree days!

looks like you have done your research, well done.

what i'd like to see (or do) is having many systems all controlled by a single switch mounted somewhere in the cabin which will change all systems between two settings. one for power and one for economy.

on the outside, it would appear much like the pwr/econ buttons you see on autos, only a lot more complex than just telling the gearbox when to shift.

if you had the money to burn this could be amazing.
i mean, it would be possible (from the push of a button) to have your car tamed for cruising, fuel mapping, boost pressure, bov noise, exhaust noise, etc all tamed down. then hit the button and have everything turn to the agressive side.


has anyone put much thought into something like this, a total system control wired to a switch with two completely different settings for different driving situations?

i like it when i see technical discussions like this, rather than "what valve caps should i get......."

looks like you have done your research, well done.

what i'd like to see (or do) is having many systems all controlled by a single switch mounted somewhere in the cabin which will change all systems between two settings. one for power and one for economy.

on the outside, it would appear much like the pwr/econ buttons you see on autos, only a lot more complex than just telling the gearbox when to shift.

if you had the money to burn this could be amazing.
i mean, it would be possible (from the push of a button) to have your car tamed for cruising, fuel mapping, boost pressure, bov noise, exhaust noise, etc all tamed down. then hit the button and have everything turn to the agressive side.


has anyone put much thought into something like this, a total system control wired to a switch with two completely different settings for different driving situations?

i like it when i see technical discussions like this, rather than "what valve caps should i get......."

Buy a MOTEC....

Any reputable ECU has duel timing and fuel maps now days, which is a flick of a switch. Things like VCT/VTEC/VVT are all able to be changed aswell via dials or inputs.

Nice work Roy, good stuff. Keep us posted on developments!

Actually selling the car, so whoever gets it will have better fuel econemy than a regular V6 anyway :D

I should get my act together and make up a batch for you guys.

Actually selling the car, so whoever gets it will have better fuel econemy than a regular V6 anyway :D

I should get my act together and make up a batch for you guys.

yep..... u should...:D

Adjusting the O2 sensor(EFIE) alone will not get any real noticable results.
I have been running my 3.5 lt TJ on Hydrogen/Petol for a year and have acheived 7.0lt/100km hwy.
At the moment I can only produce 650ml of H20 per minute, so when I can make more I'm sure it will improve.

details and pics please!