Increased MPG

[wpage]

The spacer backs the sensor off and does weaken its reading of o2 which could reduce the demand for richer fuel. Which would negate any fuel savings.
The chevy colorado gmc canyon site has a picture on one of the home made header posts where he used a bored out part from advance auto to solve his check engine alarm...

There is another device that can be built to solve the sensor issue which involves wiring resistors and potentiometers (variable resistors) These parts can be sourced at any electronics parts store like radio shack. You wire it in line and can "dial in" your sensor results to the vehicle cpu.
This "black box" is on one of the hydrogen boost sites...

[4.8t]

why not just get hptuners and tune for it? you could turn off the bank 2 o2's for the cats and tune the fueling o2's for the afr you need. problem solved. when you go in for inspection you just load the stock tune, turn off the kit and your good to go.

[6pack]

That's what I was asking a few posts up. I take it you can adjust the tune for it then.

wpage, you lost me with the first part of your post. If the input of hydrogen/oxygen causes the O2 sensors to read lean, which in turn casues the pcm to increase fuel, wouldn't causing the sensor to read less oxygen make it not ask for more fuel? Which puts us back to the original situation of using less gas. I also don't like this type of bandaid fix. I would prefer to be able to tune for the increase. But if it works it works.

I heard back from the one company today, thermo1. They said they have no problem with the O2 sensors.

[4.8t]

i'm still trying to see how it works. it seems to me that it would be rasing the air fuel ratio. so basically leaning it out. which is bad for heavy loads. why not just tune it to a higher afr to start with if that the case. in hpt there is a tab called "lean cruise" it leans out the afr when at a steady cruise with a light load on the engine. but in america its illegal do to it raising the afr which raises emmissions. so if this is doing the same thing wouldn't it be illegal as far as emmisions is concerned? anyway in alstralia they use the lean cruise thats why we have it in our hptuners program. susposely it doesn't work in american cars even if you set all the setting for a stock holden car.

[4.8t]

ok figured it out. it doesn't raise the afr it would actually lower it. the hydrogen acts as a fuel and there for burns more of the oxygen so it will show rich on the o2's. due to the lack of oxygen. so it will actually pull fuel to raise the afr back up to 14.7:1.

[6pack]

Do you have a hydrogen setup?

[6pack]

Ebay seems to have dozens of people selling these kits in one form or another. It looks like a majority of them talk about the O2 sensor problem. Most recommend the spacer talked about above that will move the sensor further out of the exhaust flow. One of the guys talks about using the foil method that my brother mentioned to me. Still researching...