Ebay item called fuel saver? Spam?


I recently purchased an item on ebay called a

“Fuel saver module”. It is suppose to add 5-10HP, raise horsepower a little, throttle response, and torque. I received it in the mail yesterday and all it is is a little piece of wire with a resistor in the middle of it. About 2 inches long. In the instructions it said to run the wire into the IAT (Intake air temperature) sensor (or MAT sensor, depending on what your vehicle calls it). Then you are suppose to leave the sensor unplugged, and cover it with electrical tape. “After installation, you should feel a tangible difference in your vehicles power and performance and your throttle response” I have felt no difference in any of these at all. Does this seem like a scam or does anyone have any ideas on whether this should work or not?


Definitely a scam. Something so simple that worked as stated would have been used by Ford or another mfr. Ford does not discover everything to improve power and mileage but they have plenty of engineers who are paid to think about this stuff. Could a vendor on E-Bay know more than Ford about power and mileage? Not likely.


your last sentence holds the key…

…whether this should work or not?

the unequivocal answer is… YES.

it got you to buy it, so yes it worked. you made someone a couple of bucks, and THAT is how consumerism/capitalism works.


This user on ebay has 98.5% positive feedback. There are thousands of users that buy his products. Ive read hundreds of his comments and very very few have anything negative to say. I left a neutral feedback comment cause im still sketchy on the product. This really bugs me, but it was really cheap and has a lifetime warranty on it and if I am not satisfied, he will refund me 100%, including shipping.


It sounds to me like this resistor is being installed in place of the temperature sensor, to fool the computer into running the engine a little rich. That might give you a little more “seat of the pants” power at the expense of fuel mileage and emissions.


Yes that sounds like what it said in the description on ebay but it also said that fuel mileage would be greater. Didnt say anything about emissions though. It said that it should run richer while increasing power, performance, and fuel mileage. It couldnt be used on diesels or turbo powered vehicles.


It’s difficult to understand how running richer would increase fuel mileage.


Here is a link to one of his products for a Jeep Liberty. He has one for a lot of different types of vehicles.



Well, I was close; they are actually claiming that they are fooling the system into running leaner (stoichometric levels) to increase the mileage. I would be careful (if it’s actually doing anything) because running too lean can increase your engine temperatures). I would probably remove it, it’s very unlikely to help and could actually do some damage it it causes the engine to run too lean.


I ran the truck close to 60 miles today with the A/C running and did watch the temp guage. I was wondering myself if it was going to increase so that is why I kept my eye on it. It never increased any more than it normally does. This was all interstate travel. Is there any other damage that it can do besides overheating?


Honestly, I can’t say without knowing what this thing is actually doing. They are claiming it is running leaner, but we don’t really know if it’s doing anything. If the engine is running lean it could increase the exhaust gas temperature, which may not cause the coolant temperature gauge to increase. I suspect it could also increase the NOX emissions. I would be a little concerned about the exhaust valves it is actually running too lean.

Do you really think these guys can improve on the original fuel injection system design (without any downside) by adding a $2 resistor? I really don’t think I would leave it installed.


Yeah I think you are right. I will uninstall the product tomorrow morning and then contact the seller to see what I can do about getting a refund. He claims he will refund anyone who is not satisfied so I will try it. Thanks for the help. Its much appreciated.


I think the IAT is a thermocouple whose resistance changes based on the temp of the incoming air. It is one of the input used by the PCM to determine fuel/air mixture. Depending on the value of the resistor it may fool the PCM into thinking the incoming air is cooler (denser) than it is and thus increaseing the amount of fuel added to the mix. At least for Dodges it is only effective at wide open throttle. At better write up is at this link. It’s only a 25 cent resistor don’t expect miracles.


Ed B.


Actually, if you read his link, they are claiming that it’s going to run leaner (to increase mileage) which is what makes me nervous.


I wish I could find a miracle. My 97 Dodge Ram 2500 could use something to make the mileage a little better. I was desperate to find anything because this is my only transportation to get back and forth to work. 178 miles a week. It doesnt sound like much but it adds up when I have to fill up at almost $100 a week.


It’s difficult to understand how running richer would increase fuel mileage.

I remember studying this back in my internals engines class. I recall it went something like this:

Increasing the fuel to a 110% stoichometric ratio improved both fuel mileage and power. Above 110% the mileage began dropping off, but the power kept increasing until it got to 116%. Then power dropped off too.

The rationale for the above was something like: there is very little time during burning to ensure that every oxygen molecule has an adjacent fuel molecule next to it. Increasing the fuel in the mixture helped to ensure that.

We even had a small dynamometer where we were able to measure changes like this.



Those ratios sound correct, engines are normally designed to operate at slightly above the stoichometric ratio to ensure complete combustion and maximize efficiency. The fuel injection system should already be designed to operate at that point, it’s unlikely that changing the ratio away from the stock system will increase efficiency.


It’s a scam, pure and simple.

Not to burst your bubble, but the seller’s feedback is not that good. He has a 96.5 rating and seriously, in the eBay world that is considered bad.
For what it’s worth, I’ve been on eBay for 10 years and would never even think of bidding on something from someone with that low a percentage.
(In spite of being called a low down crook on another thread today, I’ve managed to maintain a 100% positive FB rating so take that you know who.):wink:

The seller also has a number of neutrals and a number of those “positive” feedbacks should really be considered negatives at the worst or tepid at best.
Many other positives are from people who are too jaded to know they been had.


If you drive the car hard and make it perform, some computers will adjust for that type of driving and will be likely to add more power than a dollar resistor. The resistor might even cut your top performance down a bit. You might not even notice it. There is nothing like wrong information to hamstring a computer.


If you’re spending around $100 a week to go 178 miles, you’re only getting around 5-6 mpg assuming you’re putting 30 - 33 gallons a week into the tank. A 2500 with the 5.9/360 engine is rated 11/15 mpg, a little less if it’s 4wd. You should be getting a least 10 mpg.

Have you done the basics; plugs, air filter, fuel filter? How’s your tire pressure, are you running off-road tires, generally the more aggressive the tread the bigger the hit on gas mileage. Driving style, foot firmly pressed to the floor or do you pretend there’s an egg between the pedal and the floor? Do you find yourselve using the brakes a lot and hard or do you let the truck coast as far as you can before gently applying the brakes?

Don’t laugh, but last summer when gas hit $3/gal I put my bike on the hitch rack, took it to work, left the truck at work and rode home on the bike. The next day I rode the bike in and drove home. Do this once or twice a week, you could save some bucks.

Good luck,

Ed B.