OBDII Fuel Saver

November 4, 2018

Categories: Skepticism , Tags: Scam, OBDII, OBD2, Car, Fuel

A friend sent me a video (opens new window) the other day about a fuel saving device for your car. The video was quite well done, and like so many videos on FB had no voice over - instead having a soundtrack, along with large subtitles telling the story:

The story is about an Auckland man, Matt Davis, who realised that you can reprogram your car to be more fuel efficient, and save 30% on your fuel costs. All it requires is for a device to be plugged in to the OBDII connector of your car - and all modern cars have to have one of these connectors. The idea is that the device tunes the Engine Control Unit (ECU) of your car to increase efficiency.

The video goes on to talk about the conspiracy of Big Oil, who don’t want you to have a more efficient car.

I’ve played around with OBDII before - I’ve fixed my car using a laptop when I was having airbag sensor problems, and helped a friend who was thinking of starting an ECU reprogramming business. The idea that there’s a device out there that can make your engine work better, and that the device works for all cars, is naively silly. The protocols for talking to a car via OBDII are not standardised, and it’s taken me a while at times to be able to talk to a car and get any response at all through the connector.

I looked into the video, and couldn’t find Matt Davis - the engineer in Auckland, or his company EcoFuel. What I did find was that the device featured in the video is being sold by the company who made the video - Amazing New Tech (opens new window).

The device is being sold for $75, but an identical device is available from AliExpress (opens new window), a cheap Chinese online store, for about $3. I’m pretty sure that these devices do nothing more than flash an LED, which is powered by the car battery when you plug it in to your OBDII connector.

I’ve ordered a couple of these devices and will get a friend who is an electrical engineer to pull it apart and see what it actually does.


The way I think these devices actually work is purely in the mind of the people using them. Once someone has plugged one of these into their car, and is looking for a positive result, they will tend to use confirmation bias and a willingness to believe to decide that the device is really working. Of course, this kind of personal anecdote is no way to measure a device like this - proper controlled tests are needed, although it would also be easy to just look a the engine ECU before and after using one of these and seeing if the ECU fuel profiles have actually changed.

It’s probably better off that this device does nothing - if it actually did reprogram a car’s computer, it’s much more likely to cause problems than improve your fuel efficiency. Cars are already tuned to take into consideration not just fuel efficiency, but also emissions laws and longevity of the engine.

It makes me wonder how many other overpriced devices are being sold on Facebook using slick videos as an advertising medium. These kinds of videos are very popular, so I’m guessing it’s an easy way to make a quick buck.