I looked into OBD2 fuel savers, and found a much safer solution to save car gas instead

What happened

One thing that I've noticed making the rounds recently is "fuel saving" "economy chip tuning box" OBD2 dongles. I've had quite a few readers ask me to think about them. So let's take a look inside one of the most common ones I've seen, and see why, at best, it's a box with blinky lights, and at worse, it's something that can damage your car.

It'll blink if you connect it to your car (I'm not going to do that, and I'll explain why in a bit), but I can make it do the same blinking by connecting it to a 12V power supply.

It's a modern smoke-and-mirrors trick. So why don't I like these?

Well, beyond the fact that people are paying good money for a box that flashes, these can cause problems. I've seen badly assembled examples where bits of solder and wires rattle around inside, which could cause short circuits and even fires (and let me tell you now, a car fire is really bad news).

The other problem I've seen with these sorts of dongles is that the pins can come out and get stuck in the car's OBD2 port, potentially damaging it.

Why it matters

This is one of many fake fuel savers out there. The good news is that they're all easy to spot -- they all look pretty much the same, the wording includes techie stuff like "OBD2" and "tuning box," and they push simplicity of use ("plug and drive" is a common phrase), and make totally over-the-top promises when it comes to fuel saving.

The lie that you're told on the box and the sales literature is that you plug the dongle into your vehicle's OBD2 port, fiddle with the reset button on the dongle, start the car, watch the cool blinky lights, and the dongle will remap your car's computer as you drive, saving you money and lowering your emissions.

Sounds too good to be true, right? Well, you know what they say!

As for price, I've seen these vary from a couple of dollars to over $30 for two.

The dongle and the literature look good and make some big promises. I even get a 2-year warranty! Wow!

The problem is, there's nothing inside beyond the circuitry needed to make some LEDs blink. Yup, really. That's all it is. I took one apart, and there I found a timer chip, a few LEDs, a few resistors, and a button.

Only three of the prongs are connected to anything!

What to watch

Damage your car's OBD2 port, and you're looking at a seriously expensive repair.

Want to save money every time you drive? Forget the scam dongles and do the following: Do this, and don't plug sketchy things into your car.