Tuesday, September 26, 2023


Fuel-saving gadget is being promoted everywhere you look. Good thing or rip-off?

With motor fuel prices higher than an upset cat’s back, who wouldn’t want to increase their fuel economy? Recently a slew of articles have appeared in legitimate media for little devices that plug into your vehicle’s OBD2 port. They make comforting promises: “Lower your car’s fuel consumption up to 45% with this amazing device.” [fuelfixpro] “EcoOBD2 adjusts itself to the vehicle, according to the driver’s habits and always maintains the remapping ECU to save fuel and reduce discharge.” “EcoOBD2 Saves 15% fuel for Benzine cars.” Drop your consumption by 45%? Are these fuel savings for real?

“One size fits all”?

How do these “fuel-saving devices” work? The typical advertisement says something like this one, from EcoMaxFuel: “Every modern car made after the year of 1996 has an ECU (Electronic Control Unit). This is the car’s brain, and it monitors the performance and optimization of the engine. Once installed and you’ve driven around 150 miles with the EcoBox Fuel Saver connected, it will have enough data to begin tuning your car’s computer for lower fuel consumption.”

RV diesel rig owners have been using electronic chip technology to help them develop more engine power for years. But no matter what engine you have, you can’t just buy a “generic” chip and plug it into your rig. Each chip is specifically designed for the rig, year, and model. Engineers analyze how each vehicle’s computer operates, and “map” a variety of parameters to make it all work. With all this work, it’s no surprise you’ll spend a few hundred bucks for an aftermarket chip. It’s not some sort of “one size fits all” affair.

Video reveals the truth

With that in mind, it’s reasonable to ask: How can somebody reprogram an ECU with a fuel-saving device that sells for anywhere from less than $10 to up to $70? And how can these fancy fuel-saving devices do “one size fits all” for literally hundreds of different vehicles? The simple answer is—they can’t.

So, just what are you getting if you buy one of these little plug-ins? Put simply—a little plastic box with a blinking light. We found an exposé YouTube video that shows just what you get. David Jones, an Australian engineer with a Type A personality, has been cranking out weekly YouTube casts under his EEVblog. Jones says he has a 25-year history in electronics design.

What’s really under the hood

Jones took the cover off an “ECO OBD2” fuel-saver device to figure out exactly what it does—or doesn’t—do. If you have a few minutes, we recommend you watch the video for the more technical details. We’ll break it down to the simplistic.

What’s inside? A circuit board, some light emitting diodes (LEDs) and an integrated circuit device. Just what kind of integrated circuit it is, couldn’t be told. Jones discovered that the identification numbers that would show just what the device is had been cleverly scrubbed off. There’s also a “reset” button, which the instruction set prompts you to push on installing. Oddly, the instructions don’t tell you where to find it.

On his test bench, Jones applied power to the appropriate connectors to simulate the device being plugged into a vehicle’s OBD2 port. With the cover off, three different LEDs began to flash in a particular sequence. Interestingly, the customer will only see ONE of these lights—the other two are under the opaque plastic cover. If the light you see flashing is indicating the “fuel saver” has made a connection with the vehicle’s ECM, think again. The LEDs flash in sequence when the power is applied—without even being attached to an OBD port.

“Reprogramming” signal won’t ever get to your engine computer

A closer examination reveals that any reprogramming signal that this device could send out to the ECM would never get there. Two resistors of such a high value are plumbed into the leads that reach out to the ECM. These effectively squelch any signal that might be sent. Further, about half the pins of the integrated circuit aren’t even connected to the circuit board itself. A major tipoff that “something is rotten in Denmark.”

When Jones connected the fuel saver to a live OBD2 port, the findings showed more baloney. With the device plugged in the port, the LEDs sequenced exactly the same, regardless of whether the engine was off, in “key on” position, or actually running.

Here’s the bottom line. The device does NOTHING to communicate with a vehicle’s ECM, and so can do NOTHING to alter fuel efficiency. Jones’ bench test did reveal that the ECO OBD2 device did do one thing for a vehicle: Draw power. Anytime the box is plugged into the OBD2 port it draws 50 milliamps, “draining a 40-amp-hour battery in a month,” concludes Jones.

Sucker born every minute. Don’t be one

Here’s a screen cap from the Renton Reporter (Renton, Washington)

No matter how much money you spend, you’ll not be saving a cent in fuel costs. Like Barnum said about a sucker born every minute. There are plenty of outfits that want to take your money. Articles about how “great” these devices are for fuel saving have appeared around the country in legitimate newspapers. They look like genuine news articles. It’s only when you reach the bottom of the story do you read that these aren’t true reviews, but paid advertisements. On Amazon.com, there are about a dozen or so of these “fuel savers” luring customers with siren songs of increased fuel economy, boosted power, etc.

Want to save money? Keep your tires properly inflated. “Keep your foot out of the pot,” meaning, slow down, and don’t do jackrabbit starts. Just these two tricks alone are GUARANTEED to save you more fuel than any of these plug-in “miracles.”

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Russ and Tiña De Maris
Russ and Tiña De Maris
Russ and Tiña went from childhood tent camping to RVing in the 1980s when the ground got too hard. They've been tutored in the ways of RVing (and RV repair) by a series of rigs, from truck campers, to a fifth-wheel, and several travel trailers. In addition to writing scores of articles on RVing topics, they've also taught college classes for folks new to RVing. They authored the book, RV Boondocking Basics.


  1. I bought bully dog chip claiming better mileage for my diesel ? Wrong it stop the overdrive kicking in! More power no, I can turn it off myself by going to tow haul . Doing so gave me 1 mpg less. Save your $300 and drive slower ! You will get to where your going 5 minute later not a big deal!

  2. everything old is new again. these “fuel savings” devices have been around for, literally, decades. now that gas is expensive the con artists are coming out of hibernation to relieve the sheep of their wool.

  3. I love this guy! Seriously well trained and discerning eye. Plus, he uses all the expressions I heard all my life. What a boondoggle!

  4. Too bad such scams exist. Actually, similar devices, OBD readers, look identical, cost far less and can help fuel economy. Mine cost $15 and connects to my smartphone by Bluetooth using a free application called Torque. It will display everything your RV or car computer monitors such as transmission and coolant temperatures, trouble codes that generate Check Engine light and most other engine parameters. Based on your input regarding vehicle weight and engine size, it will calculate cumulative as well as real time fuel consumption. If you ever wonder which MPH speed is most efficiently using fuel, an OBD reader can provide that. My 31 foot Ford V-10 Class C gets around 20 mpg – going down hill! Up the same hill, its guzzling gas at 5 mpg. Surprisingly, it averages around 11 to 12 mpg on trips which consistently matches actual mileage recorded at fuel stops. In that sense, the OBD reader can help you maximize fuel economy if you use the information correctly.

  5. Thank You for this! Typical scam. Seriously- if such fuel savings were possible, don’t you think the auto manufacturers would have already done it? Duh???? Older folks reading this will remember the countless gizmos hyped in the famous “J.C. Whitney” catalogs of yore. Amazing claims of huge performance increases, gas savings, etc…and the absolutely FUNNIEST widgets ever seen that were to accomplish the miracles! I LOVED those J.C Whitney catalogs…a big part of my youth in the 1950s and early 60s….!!!

    • Loved those “J.C Whitney” catalogs. Couldn’t wait till the newest one came out. Everything you could want to make your “ride” kool! Would spend hours combing thru the pages. Fuzzy this, blinking eyed kitties, cherry bomb mufflers and cut-outs and on and on. Simple times that are long gone but never forgotten! Oh my!!

  6. Well, I would think we could lighten the load and save wear and tear on the tires and get outstanding fuel mileage – if we just filled the tires with Helium! Hmmm? Float down the road? (…and its not even April fools day yet!)

  7. My father was a lifelong auto mechanic specializing in tuning. He used to say that if you installed every gas saving device on the market, you would have to stop and drain the fuel tank to keep it from overflowing as the miles added up!

  8. What many people don’t understand is that car and truck manufacturers already spend a lot of money tuning their engines for efficiency. With electronically-controlled fuel injection, the air/fuel mixture is already very fine-tuned for the best balance of efficiency, power and emissions. The auto manufacturers are just as interested in good mileage as you are, and they have a much bigger R&D budget than chip makers or scam artists.

    Though I guess if you want to believe that auto makers and oil companies are “in cahoots” and they’re all just out to get you, then you’ll probably believe the above scam too.

    Even the aftermarket chips are fairly poor hacks and might give you a little more power, but at the expense of mileage. Some just amplify the signal from the gas pedal so the engine thinks you’ve pushed the pedal down more.

    And stop already with the theories about how emissions requirements just rob you of power and reduce your mileage. That hasn’t been true for 25+ years.

  9. I always think to the “Dale” automobile of the future, and it’s demise in Dallas. Beautiful body with a lawn mower engine.

  10. I love this article, especially the part about the blinking lights. The fact that a scammer would go to that extent in his/her product implies he/she saw the value in it. I’m surprised at the number of folks willing to share their experience of falling for a box of blinking lights. Good for them. Lessons learned and hopefully others, prone to such schemes, will learn as well.

  11. Amory Lovins, the energy efficiency guru who has been called the “Einstein of energy efficiency” and who heads the Rocky Mountain Institute think tank designed a car in 1991 he coined the “Hypercar.” The car got over 300 miles per gallon! How did it do it? Mainly by making it not weigh as much. He used carbon-fiber for the body, etc. Other than the fuel savings of having a vehicle more aerodynamically designed so it cuts thru the wind better, it all boils down to the unavoidable fact that the more an object weighs, the more energy it takes to push it down the road. Ask any Class A owner and they will attest to this fact.

    FYI the house Amory lives in at over 7000 feet elevation in the Colorado mountains that he designed in the 1980s has no heat, yet he grows bananas inside in the chill of the freezing Colorado winters. A true visionary that’s way ahead of his time.

  12. It’s obvious they don’t work for the simple matter that you are hearing about them. If they worked the “oil companies” would have had them “bumped off” like they did to the guy that made your car run on water and the guy that made the flux capacitor that was so affective, you had to drain your gas tank every now and then as it kept filling up with the 110%.

    • Several years ago my uncle told the story about a guy that bought one of those new Volkswagen beetles and was bragging to his fellow workers how that car got 18 mpg. His friends decided to play a joke on him and they started bringing an extra gallon of gas in and pouring into his tank. After his mileage shot up to 25 mpg they started siphoning gas out of his tank killing his mpg, by several weeks his mileage was down to 12 mpg and he was totally disgusted with his VW. They finally told him what they did, said he wouldn’t speak to them for several weeks. That’s how serious some are about their mpg.

  13. All marketing or advertising is designed to affect an emotional response. The news media has learned this skill all too well.

  14. Now for the real deal. I’ve owned the Brooklyn Bridge for several years now. I acquired it off a guy named Hunter, who back a few years ago, was involved in a family enterprise who had higher expectations, and needed cash quick. I’m currently trying to put a deal together to sell the bridge cheap, but a copy of the title was somehow misplaced, and im trying to get the original off Hunter. He said he has it imaged on his laptop, but lost it somehow. If anybody can help me locate it, ill sell them the bridge cheap, as soon as i get the paperwork in order.

  15. Thank you for this research. There are, unfortunately, no shortages of rip-offs and scammers. Your report will save readers from a costly mistake.

  16. My husband is a mechanic so chances are he would have been aware of this scam but I so appreciate your investigative reporting

  17. “Articles about how “great” these devices are for fuel saving have appeared around the country in legitimate newspapers.”

    Goes to show how much the “legitimate” news media cares about the truth. Instead of doing an expose’ on these fake devices to help the public, they take advertising money and spread lies.

    These do-nothing devices have been around for many years along with many other “too good to be true” items. When an ad states improvement of some kind “up to x%” I always tell my wife….”Sure….zero is UP TO x percent, so they aren’t lieing, just being intentionally deceptive.”

    • Every legitimate news media I know of runs scam ads. Some latest examples are stock market investing, or buying your home.

  18. I bought one of these for my 2018 Nissan Frontier which are known for poor mpg. I was getting 14 mpg at the time. This comes with a 30 day money back guarantee if it’s in the original packaging and unopened, duh, how do you test it this way. Upon installation and driving the required 200 miles for it to learn my driving habits I was getting 16 mpg. Probably due to me unconsciously changing my driving habits for the device. At approximately 50 days it suddenly went back to 14 mpg, removing it I discovered a reset button and reset the button, reinstalling I started driving the prerequisite 200 miles again, before that mileage expired the reset had popped again. Repeating this procedure 2 more times I trashed it, you can’t contact the distributor or manufacturer, it was a $39.95 learning experience.

  19. I have been in the auto light truck repair industry for 46+ years. There have been countless “fuel saving devices” and remedies on the market for decades. They don’t work. During the gas crunch in the70’s the car manufacturers leaned out the carburetors so much the cars hesitated when trying to accelerate. By drilling out the jets and giving the engine more gas, the car increased miles per gallon. An engine needs the right amount of fuel to operate efficiently. You can’t change that.

  20. Ok,I’ll bite. This type of scam has very deep roots. Certainly there were Miracle Oats that turned your old hay burner into Super Percheron, then there was the 100 mpg carburetor who’s patent was bought by the oil industry, magnets to molecularly hyperdude-alate your run off the mill gasoline (if it works on cows why not cars after all they both start with “c”). Not to mention spark plugs, coils, vortex inducers, nitrogen in tires….

    • Now I know for a fact nitrogen in your tires works, I just can’t figure out how to get the 21% oxygen that’s mixed in with the 78% nitrogen that’s all ready in the air we breathe out. The 1% of unlisted gases that is also mixed in is easy, every time you plug the air Chuck onto the tire valve and it go’s pfftt that’s the 1% escaping. lol

  21. The first thing that came to my mind before reading the article was why wouldn’t the car manufacturers install such a device and then brag about how better their fuel savings are.

  22. I’ve been in the automotive industry for over 40 years and I’ve seen it all. The pills, the liquids,the atomizers, the tailpipe swirlers. The magnets. So many gimmicks. If you truly want to increase fuel economy you need three things. 1, better air flow into the engine. 2,better exhaust flow out. 3, a truly adjustable vehicle specific programmable chip that plugs into the vehicles computer directly . Anything plugged into the OBD port is just a monitor if anything. All the insurance company’s are using them to monitor your driving habits if you want the insurance discount.You upload the data and they can see how you drive. To really save fuel you will spend several thousand dollars to add the right equipment. That buys a lot of fuel. We all know what we need to do. We just need to retrain our brain to do what works. Slower speeds, tire pressures, regular maintenance. Just do what we can. In the meantime, just enjoy life, Tomorrow is not guaranteed.


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