Are Automatic Engine Stop/Start Systems a Joke?


Hi John,

I love your sessions on 2UE and other media and have great respect for your knowledge and common sense solutions. I don't have a problem as such but would appreciate your thoughts on the i-stop feature on my Mazda6 (and on other fairly new Mazdas).

New Mazda6: great car...

New Mazda6: great car...

...pity about the i-stop

...pity about the i-stop

I like the concept but cannot get used to it. I have tried to use it several times but can't get used to the "shudder" when the engine restarts. I am using 98 octane fuel and Mazda told me this would reduce the shudder considerably but I still can't hack it!

The feature is constantly turned off now. Any comments? 

Kind regards,



Hi Col,

I hate this feature too. It's an example of 'greenwashing' gone horribly, horribly wrong the auto sector. Automatic engine stop/start systems are not a net benefit to the consumer, because the reduction in refinement eclipses the (tiny) saved fuel benefit. They save approximately bugger-all fuel, and they are awful, as you correctly point out, on re-starting. Every time.


Oddly enough, Mazda disagrees:

Come to a stop and i-stop automatically turns off your engine to save fuel. The engine is perfectly positioned to leap back into action, so restarting takes much less time than conventional systems.


It's not just Mazda - these systems are utterly unrefined even in $200k Audis etc. The re-start is revolting. Bottom line: if you've got the cash to afford a new car, you can afford the fuel the engine burns at idle.

As for: the fix is to use 98RON, words fail me. You know a dealer is probably bullshitting you whenever those vocal chords are vibrating...

Mazda made a bold commitment to reducing fuel consumption across the range a few years ago, and SKYACTIV (love the name...) is the result. Generally the technology is great, but i-stop should be re-named i-hate, just for the sake of accuracy. (I also toyed with i-don't-think-so, or i-burn, the latter for the great many consumers who will, like you, leave it continually de-selected.)

Mazda is the king of the joke names for quasi-technology at the moment, with singular highlights including i-ELOOP, i-ACTIVSENSE (the art of using made-up or misspelled words, or both, in ALL CAPITALS, to emphasise the point) and KODO - Soul of Motion, which (if you believe this crap) "captures the very instant energy becomes motion". I studied applied physics, so I need the sick bag ready to even quote this guff.

Leave i-stop permanently off. It won't make any appreciable difference to fuel economy, but it will increase satisfaction levels immensely. It's a pretty damn good car, however.

Glad you like the show on 2UE and elsewhere. Nice of you to say so.

Best regards,