Brand new Mazda - Has Rough Idle - feels like it needs a tune up

madar

Contributor
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2016.5 CX 5 Touring AWD, 2015 SCION XB
Right church, wrong pew. 2018 model has cylinder deactivation, no? Could be something going on with that.
 
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'18 Mazda CX-5 Akera KG i-Activ AWD 2.5L In Sonic Silver
Right church, wrong pew. 2018 model has cylinder deactivation, no? Could be something going on with that.

Yes it has cylinder deactivation but has nothing to do with it.

All SkyActiv engines idle roughly (aka loud) when first started up. After a few minutes, they settle down.
 

madar

Contributor
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2016.5 CX 5 Touring AWD, 2015 SCION XB
Read it again, he saying when at a red light, and yes, a problem with cda is possible, he needs to define rough
 
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'18 Mazda CX-5 Akera KG i-Activ AWD 2.5L In Sonic Silver
Read it again, he saying when at a red light, and yes, a problem with cda is possible, he needs to define rough

I don't understand what this has to do with cylinder deactivation (uhm)

My response to their post:

If I am not mistaken, that idle RPM is a bit low. Should be similar to 2.0L SkyActiv engine which is around 700-750rpm.

I have cylinder deactivation and my idle revs are not low like theirs and mine idles smoothly.

Sounds like a simple calibration is required to their engine to get the idle revs back to normal range.
 
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2018 CX5
My understanding is that Cylinder Deactivation only happens when cruising along, not when stopped. It would have been nice if the dash had a light to tell you when you are only firing on 2 cylinders. Our 2018 is smooth at idle, not rough at all. Take it to the dealer.
 
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2021 CX-9 Sig
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2014 CX-5 GT
My understanding is that Cylinder Deactivation only happens when cruising along, not when stopped. It would have been nice if the dash had a light to tell you when you are only firing on 2 cylinders. Our 2018 is smooth at idle, not rough at all. Take it to the dealer.

Yeah, and I think it only works in small situations - like 45-50 MPH and only in cruising situations.
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
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Plano, Texas, USA
I don't understand what this has to do with cylinder deactivation (uhm)

My response to their post:

I have cylinder deactivation and my idle revs are not low like theirs and mine idles smoothly.

Sounds like a simple calibration is required to their engine to get the idle revs back to normal range.
I agree with madar - a problem with cylinder deactivation is possible to cause rough idle. Your smooth idle with CD doesnt mean others are the same. Any failed components, or some software glitches of the CD can cause rough idle.

Idle control has its own feedback system base on multiple sources of information. It should adjust the idle RPM correctly by itself especially on a brand new 2018 CX-5. A simple calibration, if theres a way, most likely cant fix the rough idle or low RPM issue.
 

madar

Contributor
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2016.5 CX 5 Touring AWD, 2015 SCION XB
It's a possibility because it's new technology, I didn't say it was likely. I was merely pointing out that the original post was about a 2014 cx5, different design than the 2018 which is slightly more complex hence could be more problematic. And if you discount anything for no reason that could be a problem, you could potentially miss the problem. It doesn't matter when it's supposed to be activated, a failure in that systems components could cause a problem anytime.
 
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'18 Mazda CX-5 Akera KG i-Activ AWD 2.5L In Sonic Silver
We might never know if cylinder deactivation was the cause or something else as they have not returned to tell us.
 
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'18 Mazda CX-5 Akera KG i-Activ AWD 2.5L In Sonic Silver
My understanding is that Cylinder Deactivation only happens when cruising along, not when stopped. It would have been nice if the dash had a light to tell you when you are only firing on 2 cylinders. Our 2018 is smooth at idle, not rough at all. Take it to the dealer.
Correct. Only works under certain throttle input among other things
 

madar

Contributor
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2016.5 CX 5 Touring AWD, 2015 SCION XB
I agree with madar - a problem with cylinder deactivation is possible to cause rough idle. Your smooth idle with CD doesn*t mean others are the same. Any failed components, or some software glitches of the CD can cause rough idle.

Idle control has its own feedback system base on multiple sources of information. It should adjust the idle RPM correctly by itself especially on a brand new 2018 CX-5. A simple *calibration*, if there*s a way, most likely can*t fix the rough idle or low RPM issue.
Yep, more moving parts in something that already has a lot of moving parts, not a trusting scenario IMO. Make no mistake, what Mazda has done with SkyActive engines is remarkable and they do it very well, and their version of CD may work better than the competition. I've driven the 18's and they are remarkably smooth, you never can feel when the switch off happens.
 
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I've lurked this forum for quite a long time, but for some reason it was this thread that finally got me to register.

It's possible what he is experiencing is the cycling of the A/C compressor. In my '17 CX-5 this produces a slight but clearly noticeable shudder every few seconds as the magnetic clutch for the compressor engages and disengages. I've honestly found it a bit disappointing since the engine idle itself is quite smooth, but these shudders are pretty easy to feel.

As for engine idle speed..... most of you feel that 750 RPM is typical? Mine idles at 750 RPM only when the A/C compressor is running. If the engine is fully warm and the A/C compressor is off my CX-5 engine idle is just a hair over 500 RPM. I would say 510-515 RPM. I was pretty surprised by it at first as that seems low, especially for a 4 cyl. but the most interesting part is that the engine idles the smoothest at this speed. I can't even tell it's running at the 500 RPM idle, and I'm the extremely picky type that can hear/feel literally every little thing so for me to say that is pretty high praise.
 
My previous car had an extremely rough idle, so rough in fact that I had to put it in neutral every time I stop so it doesn't disturb the people around (and embarrass me in the process). When I bought the CX-5 I was really looking forward enjoying some shake free time idling on a stop light, but that has not materialized so far. I don't mean that is as bad as my old car but definitely not as smooth I as had hoped. It is not the warm up cycle it goes through at cold start. The shaking is very evident at all times regardless how wormed up the engine is. The best way I can describe is as having one of those cheap seat massagers (that basically only vibrate) turned to low setting. Putting the cat in neutral does not seem to help a lot. The vibration is not even either, it sorts of goes through short cycles with slightly rougher bumps feeling almost like miss-fires. I thought that I got some bad fuel, so I ran it almost dry and changed gas stations, but it made no difference. I know upfront that the Skyactive engine is not the smoothest out there, but many people report that they can not tell at all when the engine is wormed up and in idle. Anyone else having this issue?
Mine is doing the same...Mazda CX-7. Have you by chance figured out what it is?