Scam alert: Don't waste your money on 'car fuel savers'

HANOVER: Car fuel savers, electronic devices which claim to be able to save you money by reducing your car’s fuel consumption, are widely available online. But do they actually work? In a word, no.

The plug-in modules connect to the diagnostic interface (OBD2), which has been available in almost all vehicles for around 20 years and is used by workshops to read vehicle data or faults.

However, a test by c’t magazine found that none of the tested connectors could communicate with the engine electronics system at all.

The testers found that the device makers use several tricks to convince motorists that the fuel savers are doing something useful.

One is to use different plug colours, for example blue or red for diesel, green or yellow for petrol. In reality, the colours are meaningless.

Then there are switches that the driver is supposed to push at a certain moment. That’s just a distraction tactic, the testers say. At most, the button only changes the flashing of the LEDs on the plug-in.

It might also lead the driver to blame themselves if there are no fuel savings, thinking that they didn't press the button at the right time.

The scammers also urge drivers to be patient, saying that the optimisation of the vehicle's electronics takes effect only after 200km of driving at the earliest. Only after that will the savings effect allegedly kick in.

"As was to be expected, simple OBD2 plug-in modules do not save fuel,” the testers concluded.

Even if it were possible to here and there trim the engine management system — which has already been optimised by the manufacturer — to achieve better fuel efficiency, much greater technical effort would be required than a simple plug-in is capable of.

As well, a plug-in that actually interfered with the engine control system would need to be officially approved for each specific vehicle type and might void the warranty.