Loud exhaust on morning startup

L

lcann25

Member
:
2014 CX-5
Anyone else notice this, or is there something wrong with mine?

On first startup in the morning there seems to be much more noise coming from the exhaust, but almost like the noise is coming from the engine bay area for 15-20 seconds then the noise goes away and becomes much quieter. I made a point of starting it this morning and then jumping out and listening to the outside and this confirms a lot more noise coming from somewhere other than the rear tailpipes. Now don't mistake this for the higher engine RPM that is associated with the morning startup, because this noise starts and goes away while the engine is still in it's higher RPM range. Is this something that is supposed to happen to somehow warm the engine quicker, or should I look at taking it in? This is a Canadian 2014 model with the 2.5 if it matters.

Thanks
 
This is normal. The computer retards the valve timing for 15-20 seconds when you first start it cold to quickly warm up the catylitic converter. When the engine runs in that mode it sounds like a crappy Diesel engine and even sometimes sounds like it misfires but its all normal for the skyactiv family of engines. I think this is covered in the owners manual and its been covered a lot on the forum.
 
I was hoping Mazda had figured out a way to re-engineer this noisy startup procedure that make the vehicle appear so cheap when other manufactures don't have this issue. Ed
 
Sorry to bring up something that has been covered, I just wasn't sure what to search for.. I'm glad it's normal and I can live with it for the incredible gas mileage these vehicles are getting. I've got just over 600 miles on mine now and took a little highway trip and got over 31mpg, which I am impressed with and I'm sure will only get better as it breaks in.
 
erhayes said:
I was hoping Mazda had figured out a way to re-engineer this noisy startup procedure that make the vehicle appear so cheap when other manufactures don't have this issue. Ed
Click to expand...

Uh no other manufacturer has the same engine.
smh
 
FWIW, my Sonata has a noisy startup too, but it's mostly the injectors. At first, I thought it was the wastegate rod actuator rattling, but then I drove a naturally-aspirated Santa Fe that did the same thing. It only does it for about 10-15 seconds before quieting down.
 
lcann25 said:
Sorry to bring up something that has been covered, I just wasn't sure what to search for.. I'm glad it's normal and I can live with it for the incredible gas mileage these vehicles are getting. I've got just over 600 miles on mine now and took a little highway trip and got over 31mpg, which I am impressed with and I'm sure will only get better as it breaks in.
Click to expand...
If you've had your CX-5 for 600 miles, it's high time to peruse the owners' manual. All this is covered therein!
 
erhayes said:
I was hoping Mazda had figured out a way to re-engineer this noisy startup procedure that make the vehicle appear so cheap when other manufactures don't have this issue. Ed
Click to expand...

Well that is somewhat of an unreasonable statement. The fact that Mazda uses an airpump and retardation of timing for such a short period of time (<15 secs) to warm up their engines and catalytic converters is actually an advancement in engineering... It was less than a few years ago where cars would idle at 2000-3000 RPM for over a few minutes creating extended periods of engine and exhaust noise while wasting significant amounts of fuel since they run quite rich during the warm up period.

Take it from someone that is a Mechanical Engineer...
 
Don't get the diesel, that will really sound cheap all the time and not just for 10 seconds.

Sorry erhayes, couldn't resist.
 
lcann25 said:
Anyone else notice this, or is there something wrong with mine?

On first startup in the morning there seems to be much more noise coming from the exhaust, but almost like the noise is coming from the engine bay area for 15-20 seconds then the noise goes away and becomes much quieter. I made a point of starting it this morning and then jumping out and listening to the outside and this confirms a lot more noise coming from somewhere other than the rear tailpipes. Now don't mistake this for the higher engine RPM that is associated with the morning startup, because this noise starts and goes away while the engine is still in it's higher RPM range. Is this something that is supposed to happen to somehow warm the engine quicker, or should I look at taking it in? This is a Canadian 2014 model with the 2.5 if it matters.

Thanks
Click to expand...

You should've mentioned it sooner. CX-5's are grumpy without their bacon in the morning. In your case it's Canadian bacon lol.
 
You make some good points SayNoToPistons, especially the 2K startup although if pressing the accelerator ~ 1/2 inch while cranking results in a 1,200 Rpm startup idle.
Taken with pleasure from a Mechanical Engineer to someone who is a degreed Physicists.
 
Subject: Whining sound from the engine compartment after starting a cold engine


DESCRIPTION

Some customer may complain about a whining sound which is heard from the engine compartment for about 20 seconds after starting the cold engine.

This is for improved exhaust gas purification and does not indicate defect of the parts.

OCCURRENCE MECHANISM OF WHINING SOUND:

The SKYACTIV-G engine is employing the 4-2-1 exhaust pipes to improve the fuel economy and engine power.

But the distance from engine to catalytic converter is longer than for previous engines such as LF engine, and it takes longer time to warm up catalytic converter than at LF engine.

To improve this condition, the new idling control is employed to burn the fuel inside the exhaust manifold for 20 seconds to quickly warm up the catalytic converter, and this burning sound is heard as whining sound.

https://docs.google.com/folder/d/0B...NUajA/edit?docId=0B-sY4-KaDJV-a0kzRXVwZ1ZVY0E
 
Pongchanok said:
Subject: Whining sound from the engine compartment after starting a cold engine
Click to expand...

I've only run into that sound from the engine once but it really struck me as odd since it was new and unexpected. To me it sounded like they were grinding concrete in the distance. I don't know if you've been around an area where they were resurfacing concrete roads/bridges but it sounded like that but faint like it was in the distance. As soon as I realized it was my car I shut it off then restarted and the noise came back. It went away as I got to the edge of the parking lot but it really had me worried that there was a problem until I read the bulletin about it.
 
I kind of like it -- but I am also that guy that loves the sound of Diesel engines.
 
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