Danged Automatic!

[Anchorman]

I've never driven a vehicle with CVT. What's the issue with that transmission?

It*s a constantly variable transmission so it uses a pair of variable v pulleys to give different ratios at a near constant engine speed. If you press the loud pedal it tends to rev the engine quite high. They are a lot better than they used to be but still not as good as a conventional transmission as a general rule.

 

[Ceej007]

I have had my car do something similar now twice. Accelerating onto a highway, giving it a lot of gas. Then I let off the gas a bit and it should shift but it just keep on revving and revving.

Very odd and disconcerting.

 

[HyFlyer]

I have had my car do something similar now twice. Accelerating onto a highway, giving it a lot of gas. Then I let off the gas a bit and it should shift but it just keep on revving and revving.

Very odd and disconcerting.

I think that is the "zoom-zoom" way of Mazda. I personally like it. I'm glad that if I'm accelerating hard and let off that it does NOT instantly upshift to "save fuel" but rather holds the gear and makes for better performance should you want to "get on it" again. Also works pretty well on back road romps going through curves where I'm on and off the gas. Not as good as a manual but pretty impressive (I think) for the car to sense your driving mood

 

[Unobtanium]

I have had my car do something similar now twice. Accelerating onto a highway, giving it a lot of gas. Then I let off the gas a bit and it should shift but it just keep on revving and revving.

Very odd and disconcerting.

It's normal, so that if you need to suddenly get on it again, no shifting needs to happen. Mazda automatics drive like I drive a standard.

 

[AVC]

Pitter, the accelerator has a "kickdown switch" just for situations like these. When you press the accelerator as far down as you think it will go, press it a little harder, and you should feel a click. This is the kickdown switch. It will force the car to downshift. Try it on an empty back road to see if it helps.

I thought this was true until a few days ago. The service lit says this is just a mechanical detent. No switch. No kickdown function.

 

[sm1ke]

I thought this was true until a few days ago. The service lit says this is just a mechanical detent. No switch. No kickdown function.

Are you referring to this? I understand that there is a difference, but doesn't it function in a similar enough manner to be called the same thing?

 

[AVC]

Our business blocks European continent URL's, so I can't view the link. The accelerator pedal is a non-serviceable unit, with 6 wires; 3 for circuit A sensor, 3 for circuit B sensor. The "click" you feel in your foot is just a mechanical detent. It does nothing other than tell your foot that you are fully maxed, pedal to the carpet, 100%, all she's got.

 

[sm1ke]

Our business blocks European continent URL's, so I can't view the link. The accelerator pedal is a non-serviceable unit, with 6 wires; 3 for circuit A sensor, 3 for circuit B sensor. The "click" you feel in your foot is just a mechanical detent. It does nothing other than tell your foot that you are fully maxed, pedal to the carpet, 100%, all she's got.

This is some of the text from the link.

If the accelerator pedal is depressed carelessly, kickdown control will be implemented based on the accelerator pedal being determined as fully open, and vehicle shock will occur. A kickdown switch has been adopted so that it can be determined that the accelerator pedal is fully open based on the driver’s intention of depressing the accelerator pedal for kickdown.

A load can be felt while the accelerator pedal is being depressed and when it is further depressed the kickdown switch turns on.

The driver can control the kickdown by knowing the amount of accelerator depression.

The kickdown switch is only a measure of the kickdown. An electrical signal is not transmitted by the kickdown switch turning on/off, and vehicle control is not affected.

Sounds like it's basically an "are you sure" button. While the switch itself doesn't do anything, depressing the accelerator pedal past the "kickdown" puts it at 100% throttle, triggering a downshift/kickdown, just like a true kickdown switch would.

Please let me know if I've misinterpreted something.

 

[AVC]

Well, my point is that it is not a "switch", but rather a detent in the accelerator travel. There is a Mazda marketing video that suggests the detent actually commands the PCM from best fuel economy mode to max power mode, but if you watch the output of the accelerator pedal PID's for circuit 1 & 2, pressing past the detent does nothing (no sudden jump in output) electrically that I saw. Maybe I missed it or my scan tool was too slow to catch it? And there certainly aren't extra wires in the connector dedicated to a detent switch.

As far as I can tell, *rapidly* pressing the accelerator to above 95% or so is sufficient--like all modern cars-- for the PCM to get the "so you want FULL steam" message. The detent seems to be feedback to your foot that you have done so, in Mazda zoom-zoom fashion.

 

[Unobtanium]

Well, my point is that it is not a "switch", but rather a detent in the accelerator travel. There is a Mazda marketing video that suggests the detent actually commands the PCM from best fuel economy mode to command max power mode, but if you watch the output of the accelerator pedal PID's for circuit 1 & 2, pressing past the detent does nothing (no sudden jump in output) electrically that I saw. Maybe I missed it? And there certainly aren't extra wires in the connector dedicated to a detent switch.

As far as I can tell, *rapidly* pressing the accelerator to above 95% or so is sufficient--like all modern cars-- for the PCM to get the "so you want FULL steam" message. The detent seems to be feedback to your foot that you have done so, in Mazda zoom-zoom fashion.

I agree with this. Matches my experience.

Back in the day when I drove an LS1 car, some people noted low trap speeds and wondered "WTF?" Turns out their floor mat was under the pedal, lol! Maybe this is a failsafe for something like that. "Hey? This feels different...". Who knows. It's a weird feature.

 

[sm1ke]

Sounds like it's basically an "are you sure" button. While the switch itself doesn't do anything, depressing the accelerator pedal past the "kickdown" puts it at 100% throttle, triggering a downshift/kickdown, just like a true kickdown switch would.

As far as I can tell, *rapidly* pressing the accelerator to above 95% or so is sufficient--like all modern cars-- for the PCM to get the "so you want FULL steam" message. The detent seems to be feedback to your foot that you have done so, in Mazda zoom-zoom fashion.

It seems that we're saying the same thing. Mazda calls it a switch, but its just a feedback mechanism to tell the driver that they've hit 100% throttle.

 

[murky]

It seems that we're saying the same thing. Mazda calls it a switch, but its just a feedback mechanism to tell the driver that they've hit 100% throttle.

Interesting conversation. AVC approaching from the engineering perspective, and some of the other comments more user experience and/or marketing perspective.

One difference between what AVC describes vs. the description of an actual kickdown switch is that presumably a physical switch could have a step function response, even if one slowly depressed the pedal, held it just shy of the switch for several seconds, and then nudged the pedal the last 1% of travel to engage the switch.