Cold Starts - 2012 Mazda Mazda3 Long-Term Road Test
ADVERTISEMENT

2012 Mazda Mazda3 Long Term Road Test

2012 Mazda Mazda3: Cold Starts

June 14, 2012

2012 Mazda Mazda3

The Skyactiv-ness of our longterm 2012 Mazda 3 is the real deal, as we've confirmed in our recent fuel economy test of 40-mpg cars. We used a 3 sedan for that test, by the way.

Somewhat related: one thing I've noticed about the Skyactiv engine in our longterm car is a muted high frequency 'shh' noise (it's not exactly a ticking, more like the sound made by tiny pebbles placed on the exhaust heatshield of an idling engine) during cold starts. Some owners might mistake the source as being from the engine's direct injectors.

Turns out the exhaust manifold has thin walls and thus transmits more combustion noise than if it was some old-school cast iron chunkus. When cold, the ignition timing is retarded which puts more heat into the catalyst to aid light-off. This retarded timing also has stronger exhaust blowdown pulses, and that's what you're hearing. 

The sound is hardly annoying, but it's there. And it's normal.

Jason Kavanagh, Engineering Editor


Leave a Comment
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT

Past Long-Term Road Tests

ADVERTISEMENT
Have a question? We're here to help!
Chat*
Chat online with us
Email
Email us at help@edmunds.com
*Available daily 8AM-5PM Pacific
Phone*
Call us at 855-782-4711
SMS*
Text us at ED411