O2 Sensor Resistor
 

A friend of mine purchased an O2 sensor resistor that he added to his car and he swears he gets better gas mileage with the resistor (about 5 mpg better). I told him he probably is paying more attention to his mpg and driving more efficiently so his mpg went up.

He sent me this note that came with the part to describe the benefits of adding it to your car:

"With the new fuel injection systems of post-1980 vehicles lower mpg has been seen over time because the Fuel system runs too rich from the factory. The added resistor will automatically tune your vehicles Air/Fuel Ratio Mixture to run at stoichometric levels." It has TR-454 on the resistor as the part number.

Has anyone tried this mod with their car and what were the results? Is this a myth or something to look into? The part costs around $10 so it might be something worth trying even if it's at a $10 loss.

Do you have a link? Modern FI car are set to run at stoichometric. There are device that you run to the O2 sensor that spoofs it to run leaner then Stoichometric thus giving better mileage.

There are a lot of these tricks out there. The problem is that randomly leaning out your AFRs may be good or bad for fuel economy, but is very likely going to make your emissions worse, :p

There isn't a link for this to give you but this is the original email my friend sent me. I did not post the entire text earlier as I didn't want to make the original post too long. I think he purchased the part on Ebay but I also read somewhere that the part is available at Radio Shack.
SAVING FUEL THE EASY WAY

Performance FUEL SAVER Part#: TR-454

What you can EXPECT from THE FUEL SAVER

- UP TO 25MPG or more added

- UP TO 70+ FT. LBS. of Torque

- UP TO 70+ Horsepower

- Faster 0-60 MPH Times

- Reach Higher speeds quicker

- Greater Acceleration

- 20+% Quicker throttle response time

- Smoother shifting

If you have multiple vehicles or just are constantly on the road or travel a lot, then this will save you a lot of money. look under my other listings to see if we offer some type of fuel saving device for your other vehicles.

What you will receive

1 Fuel Saving Module

1 Set of Step by step, Easy to read installation instructions

(Installation time is approximately 5-10 Minutes at the most)

24/7 Technical Customer Support

100% Money Back Guarantee! That's right! If your module doesn't perform as you expect it to, we will refund you 100% of the original cost.

LIFETIME WARRANTY with no HASSLES!

And last but not least, 5-10 MPG Fuel Savings FOR THE PRICE OF A DVD Movie!

With all these benefits at such a low cost to you, how could you possibly go wrong?

How our module works

In all motor vehicles from the late 80's to the present time, engines run on fuel injection systems instead of the outdated carbuerated systems from the 60's and 70's. With the new fuel injection systems, we noticed a common problem among all vehicles with fuel injected systems. The Fuel system runs too rich from the factory. Our module will automatically tune your vehicles Air/Fuel Ratio Mixture to run at stoichometric levels. This in return will help you to save more fuel and since your vehicle will be tuned, you will gain horsepower while saving fuel! Since our module is inexpensive, it will pay for itself in the first week due to these high fuel savings! The best part is, you will not need a mechanic to complete the installation. With our easy to read, step by step installation instructions you will be able to complete the installation in 5-10 minutes at the very most! In fact, the installation is so simple, you will not even need any prior car experience to install our module. We guarantee you will notice the difference or your money back. The best part is the price. We can make our prices this low for the fact of having no Middleman, No supplier and we are not a company that resells for a major company. Of course we cannot guarantee you a SPECIFIC MPG rating, but we can guarantee you will see a 5-10 MPG increase in fuel savings.

Frequently Asked Questions

Question: My truck or car runs on diesel fuel, with this work for my vehicle?

Answer: Sorry, our module does not work with diesel engines.


Question: My vehicle is turbo or supercharged, will this work on my vehicle?

Answer: Sorry our modules do not work on turbo/supercharged vehicles.


Question: Will I be able to install the module by myself or will I need a mechanic?

Answer: You will be able to install this module by yourself! You will not need a mechanic to complete the installation. We include easy to read, Step by step installation instructions to complete the installation by yourself in less than 10 minutes and you will not need any prior experience. You will NOT be cutting, soldering or crimping wires to complete the install. The module is a simple plug and play installation. If you can plug a lamp into the wall, you will be able to complete the installation!

Non of that make since to me. More power torque by running Stoich. I'll let more knowledgeable folks speak to it. If it came from e-bay it sounds like the .50 cent resistor that you can buy from radio shack that you put in the IAT sensor that fools it into thinking the temperature is either cold ( performance) or hot (fuel).

This mod has worked on a few makes of cars but not many. As SVO stated it will also increase emissions:(

I say scam.

I'm skeptical as well but figured I'd run it by the forum to see what everyone thinks. I'm open to any and all opinions. On another note, the scooter I purchased is about halfway through a full tank and so far I'm at estimated 90-100mpg. Drive it to work as much as weather allows. Also, increased psi on tires on my '05 Toyota 4Runner from 36 to 45 last week and already see about 3-4mpg increase on my factory Toyota fuel gauge (from 20 mpg to 24 mpg) halfway through this last fill-up.

As SVOboy said, you can lean out your air/fuel ratio and gain mileage. NOx emissions will go up from this. In Honda's lean burn engines they have special catalytic converters to deal with this.

However, that ad is total BS. Stock systems are already designed to operate at stoimetric levels and do it very well already. Leaning out a mixture will definitly not give you more power, it'll give you less. Richening up the mixture may provide sightly more power, but result in worse mileage. I depends on how the resistor is wired to the sensor as to what it'll do.

I had mentioned this in an earlier thread along with a resistor for the air temp sensor and the idea was shot down big time. I still want to try it when I get time, but I have yet to do it.

But the increased torque and better fuel economy does not at all go together for a mod like this.

Measure the value of his resistor. Get a resistor of the same value for a penny and try it yourself. I think it must be a pretty high value resistor to make a difference, because the input resistance of the ECU must be very high. Now if you are talking about injecting a voltage into the O2 sensor wire, that is something else.

Are you suggesting pulling up the signal with a voltage gain?

Bwahahahahaha... :D

Of course, the way it's written, it doesn't say you'll gain 70 horsepower, just that you'll have over 70 horsepower when done. That's not much of a stretch for any vehicle!

With an offset. Up or down, I always get confused which way is lean and which way is rich..It is always the opposite of the opposite in my head, anyway. :D and I always have to look it up again.

I mention it for two reasons, one, I have read about it being done(never done it myself), two, I have seen a toyota technical service bulliten which talks about "oxygen sensor offset", where an oxygen sensor will develop a permanent shift of what voltage it gives out when the ratio is stochiometric (sp?). Now in the toyota TSB they look at this as a problem, because the mixture is not where toyota wants it, and they show how to look at the waveform with a scope to detect the issue.

I would think if you wanted to try it, a single 1.5 volt d cell battery, with a 10 or 20 turn variable resisitor (pot) of perhaps 10K ohms or 100K ohms around it as a divider (not just in series) so you could adjust the output voltage, would work. If you wanted the ability to go BOTH positive and negative, then 2 D cells in a bridge with the pot (again as a divider, not in series) would allow you to go either way, with the pot center as zero offset. D cells should last about forever in this application, but I expect they will change voltage slightly with ambient temperature/phase of moon/whatever. If you decide to try this, Whatever you do, start at very low voltage offsets and move up cautiously, you dont want to hurt anything.

Just an FYI, I have been soldering wires to the ends of D cells for a long time now to avoid the eventual but inevitable contact problems you can get at very low current flows. If you want to try it, first make a wetted puddle of solder on the d cell, then come back later and put a tinned wire in the puddle. Work quick and you won't heat the d cell much. Wear glasses etc. if you are worried about rupture, but my *opinion* is that there is not much risk if you work quick.