Disable Cylinder Deactivation

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Mazda
At 15:45, when the reviewer opens up the fuel economy app, it looks like what all our vehicles have, a generic fuel economy measurement that is not in real-time and indicative of CD activation. Any MPG increases during a particular time interval is purely coincidental because certain criteria must be met before CD will activate.

If you want to have a real-time CD monitoring system, it's present on all 2019+ Mazda 3 models and on the 2021 CX5,

https://www.reddit.com/r/mazda3/comments/bkaa0g
 

HardRightEdg

US 2020 CX-5 Touring AWD Soul Red
At 15:45, when the reviewer opens up the fuel economy app, it looks like what all our vehicles have, a generic fuel economy measurement that is not in real-time....
Just to be clear, that reviewer is driving the GTR with the turbo engine. Other posters repeatedly comment that this engine does not have cylinder deactivation.

As I said a couple of times, the real time MPG monitor in my vehicle (US 2020 Touring AWD 2.5L gasoline) is not a touch screen function. It is in one of the display options in the right pod of the instrument cluster. That pod has four display option. You hit "Info" on the steering wheel until you get to this display:

1602511103262.png

The gauge at the top of the display is buried at zero in this picture because the vehicle is running in park where you get zero mpg. I will not be taking video while driving. I can assure you that as the vehicle is driven that guage bounces around in real time in sync with the cylinder deactivation display. That mpg gauge can be used in lieu of the cylinder deactivation gauge if you have some other use for the screen once you know what to look for which I covered previously.

In my vehicle the cylinder deactivation monitor is displayed on the touch screen by going to Applications > Fuel Economy Monitor, not "Information > Fuel Economy Monitor" as stated by the guy you quoted who has a 2019 Mazda 3. That screen display in my vehicle looks like this:

1602512030630.png


With the engine running and the car in park, the display shows all cylinders firing. As stated earlier, my tests show this is always the case under 10 mph.

Why would it not work above 50 mph? Seems redundant if that's the case.
Wouldn't you want to have it working at highway cruise speeds?
Right. It does work at highway speeds and will go to two or zero cylinders when highway cruising under circumstances previously described unless Mazda's gauges and displays are lying. Whether there is a top end speed where cylinder deactivation is no longer applied I could not say. 75 mph is about as fast as I've been going while testing this stuff out. My guess is if you ran this thing to top speed, whatever that is, then let all the way off the gas into coast, all four cylinders would stop firing at 100+ mph.

I cannot attest to how Mazda has rejiggered gauges and displays from one model to another, one year to another, one market to another, one software update to another. But I think it is fair to say anybody with a US 2020 CX-5 2.5L with current software could reproduce my results.
 
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2010 CX-9 GT
I think most cars on the road stop injecting fuel when you are coasting down or engine braking. That's not really cylinder deactivation, it's just a benefit of electronic fuel injection. When the display says zero cylinders it's just not injecting fuel because there is no load on the engine.
 
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HardRightEdg

US 2020 CX-5 Touring AWD Soul Red
I think most cars on the road stop injecting fuel when you are coasting down or engine breaking. That's not really cylinder deactivation, it's just a benefit of electronic fuel injection. When the display says zero cylinders it's just not injecting fuel because there is no load on the engine.
I don't think so and I'll tell you why.

First, I'm looking at a "cylinder deactivation" display that shows no cylinders active under certain condition. So, the display would have to be lying.

More importantly, the display will show zero cylinders (with the real time mpg gauge jumping to and buried at 80) in situations other than outright coasting. If you are highway cruising and let off the gas enough but not all the way, you can see zero cylinders displayed and mpg buried at 80.

I think I'll stop talking about this until somebody else actually does some testing in a model with the same display features. It's pretty easy to do.
 
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2010 CX-9 GT
I don't think so and I'll tell you why.

First, I'm looking at a "cylinder deactivation" display that shows no cylinders active under certain condition. So, the display would have to be lying.

More importantly, the display will show zero cylinders (with the real time mpg gauge jumping to and buried at 80) in situations other than outright coasting. If you are highway cruising and let off the gas enough but not all the way, you can see zero cylinders displayed and mpg buried at 80.

I think I'll stop talking about this until somebody else actually does some testing in a model with the same display features. It's pretty easy to do.

The Mazda renderings of the valve train don't show that cylinders 2 and 3 are equipped with the hardware required to deactivate the valves, at least on the 2018 version.
 
I don't think so and I'll tell you why.

First, I'm looking at a "cylinder deactivation" display that shows no cylinders active under certain condition. So, the display would have to be lying.

More importantly, the display will show zero cylinders (with the real time mpg gauge jumping to and buried at 80) in situations other than outright coasting. If you are highway cruising and let off the gas enough but not all the way, you can see zero cylinders displayed and mpg buried at 80.

I think I'll stop talking about this until somebody else actually does some testing in a model with the same display features. It's pretty easy to do.
CD and coasting when no load and minimal fuel spray are 2 different things.

All 4 cylinders are not truly deactivated(changing the valves) when coasting.
 
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Mazda
I stand corrected @HardRightEdg

@2001birdowner and @Buzzman12 , the CD used to activate at only between 25-50mph (1st link) but Mazda may have tuned CD to be more aggressive in newer vehicles than older vehicles (2nd link) .


 
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GA prior 16 CX5 GT
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20 CX5 GT + Prem
I have set cruise at 75 mph and going down a slight hill it will switch to 2 cylinders if the grade is the ideal load for 2. I agree that when it shows all four off it is fuel cut mode for the last 2 but I do not know if the first 2 still have the valves closed...
 
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2018 CX-5 Sport
When I take my foot off the gas and coast, my real time MPG display goes to 99 miles per gallon, but I figured that the engine is idling using very little fuel, not that all the cylinders are not firing. If non were firing it would explain the good down hill engine braking. The transmission would be spinning the inactive engine.
 
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Northeast
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2020 CX-5 Tour
The following is taken from the 2020 CX-5 FSM, in the section 'Fuel Injection Control System':


Deceleration fuel cut zone

  • Purpose

  • Improved fuel economy

  • Control condition

  • If all of the following conditions are met while the vehicle is decelerating

    • Accelerator pedal is fully closed

    • Engine speed is specified value or more

    • Vehicle speed is specified value or more

  • Determination of fuel injection time

  • Fuel injection is stopped.

Mazda is saying that fuel injection is stopped when a set of specific set of conditions is met during deceleration. And it seams reasonable IMO to assume that this shows up on the CD display as all 4 cylinders inactive.
 
I’m surprised more CX-5 owners aren’t complaining about CD. There are quite a few complaints from CX-30 and Mazda3 owners across different forums.

It really ruins it for me. The subtle jolt when switching from 4 to 2 and resonating vibration when running on 2 cylinders under 2k is incredibly annoying for someone like me.
 
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2018 CX-5 Touring
I’m surprised more CX-5 owners aren’t complaining about CD. There are quite a few complaints from CX-30 and Mazda3 owners across different forums.

It really ruins it for me. The subtle jolt when switching from 4 to 2 and resonating vibration when running on 2 cylinders under 2k is incredibly annoying for someone like me.
Wow. Can’t say I ever felt a thing such as a jolt. If mine is switching I don’t know it.
 
Same here...I haven’t been able to tell and I’ve tried. Wish our ‘19 had the display that shows when CD active like the later cars. If nobody told me about the CD, I’d never know our cx5 had it.
 
It’s likely your driving styles or you just don’t notice it because you’re not as in tune with your cars as I am. That’s not at all meant to be offensive I’m really sensitive to things like this.

My wife has no idea it’s happening. Her driving style also includes constantly being on and off the gas, which means CD in’t kicking in as much.

If you’re cruising at around 1500 RPMs with your foot steady on the gas and light load (minor incline) it’s impossible to not notice.
 
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Northeast
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2020 CX-5 Tour
...
If you’re cruising at around 1500 RPMs with your foot steady on the gas and light load(minor incline) it’s impossible to not notice.
Add my 2020 and my daughter's 2019 to the list where this does not ever happen.

If it's 'impossible' to not notice this stuff, then it must be that it's not happening on our vehicles. And please don't suggest that I'm not 'in tune with my car', because I'm a long time DIYer, and am ALWAYS monitoring for anything out of the ordinary with all of our vehicles (which is something that my wife would totally agree with).

Sorry that your CX-5 experience has been ruined, but IMO you're not going to have very much success finding many other owners having the same issue that your vehicle has.
 

sm1ke

Work In Progress..
Moderator
Contributor
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Canada
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'18 CX-9 Signature
It’s likely your driving styles or you just don’t notice it because you’re not as in tune with your cars as I am. That’s not at all meant to be offensive I’m really sensitive to things like this.

My wife has no idea it’s happening. Her driving style also includes constantly being on and off the gas, which means CD in’t kicking in as much.

If you’re cruising at around 1500 RPMs with your foot steady on the gas and light load(minor incline) it’s impossible to not notice.

It's also possible that your car is an anomaly. Have you test-driven other CD-equipped CX-5s to see if they feel the same? I would head to a dealer to test - then you can make a case with the dealer to have the issue investigated if the other vehicles don't exhibit the issue you're describing.

A word of warning though - there is a TSB out there to troubleshoot a similar issue on the CX-30 and Mazda3, but the TSB states that the fix might make the issue worse, and if it does, at that point you'd be SOL.
 

HardRightEdg

US 2020 CX-5 Touring AWD Soul Red
I would hope not considering it was manufactured in July 2020 and I purchased it 2-3 weeks ago.

For me, the vibration that can be felt when running on 2 cylinders isn’t bad at all, it’s the transition from 4 to 2 that bugs me.

I’m sure it isn’t easy to disable, but who knows, maybe it could be as simple as the resistor mod for some Honda’s that only impacts CD( and maybe the temp gauge?).
I can't say I've detected what you've experienced and I think I'm pretty sensitive to what goes on.

As noted previously, I have noticed how this vehicle wants the gas just right to avoid lugging or jolting when shifting from 1st. to 2nd., then less persnickety from 2nd. to 3rd., and not picky after that. I've only once noticed a jerk in a downshift when easing off the gas going uphill into a no-stop 90 degree left turn, kind of an unusual circumstance. Perhaps CD has something to do with it in some circumstances (I've not simultaneously monitored the gauges under these conditions), but my take is that it is inherent in the engine torque/gear ratio/whatnot setup. It took me quite a while to get the hang of it.

When in doubt, more gas! into 2nd. and 3rd. It took me at least 3 weeks to get a better feel for it. The vehicle wants to be driven in a sporty-ish mode. If that doesn't work, I'd have the dealer check it out.
 
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It’s likely your driving styles or you just don’t notice it because you’re not as in tune with your cars as I am. That’s not at all meant to be offensive I’m really sensitive to things like this.

My wife has no idea it’s happening. Her driving style also includes constantly being on and off the gas, which means CD in’t kicking in as much.

If you’re cruising at around 1500 RPMs with your foot steady on the gas and light load (minor incline) it’s impossible to not notice.

lol perhaps, or you could just be imagining things. Sounds more like torque converter lockup to me
 

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