Automobile Start/Stop Systems

[yakers]

Any facts/studies (maybe opinions?) about the new automobile start/stop system as to the positive side (mileage, emissions) and the down side (wear/slow start)? I had a car rental in Europe and it worked well there, My wife has a Ford Fusion plug in hybrid and it works flawlessly but it is designed in and will cruise on electric. I have a new Jeep with this 'feature' and it is getting increasingly common. I think they have beefed up the Jeep battery, I hope the starter too. But I know from diesel days that they have a lot of their wear on start up and I would leave it running rather than frequent stop/start. I like saving fuel and understand emissions issues (I live in southern California) but I also want to know if there is anything to be gained or lost from turning it off.

 

[Bamaman]

You don't need to idle diesels for long periods of time. Same with gas engines.

 

[Midpack]

They do save fuel and reduce emissions and they’re designed for many more cycles on cars meant to deploy stop start. You wouldn’t want to manually stop start a car that wasn’t designed for it. We owned a Camry Hybrid for 11 years and never replaced the starter.

Did you do a search, here’s one answer https://autoweek.com/article/technology/what-auto-stop-start-autoweek-explains.

Here are others LMGTFY

 

[marko]

My past two Mercedes have had it, as does DW's.

I find it very, very annoying when in start/stop traffic and I just turn it off. It doesn't bother me when I'm stopped at a light though.

Not sure if the benefit gets cancelled out by other negatives though I tend to think that it might take as much energy to re-start and keep the A/C on etc as it saves.

Mine seems to have some little motor that keeps running to keep things going during stop; not sure if all cars have this but that must use some energy.

 

[Chuckanut]

One way to defeat the start-stop system is to drive with the heater turned up on a very cold day. The demand for passenger warmth keeps the engine running at most stops.

My hybrid re-starts so quickly and reliably that I doubt if years of driving adds much wear and tear to the starting system. Now my dad's old carburated Plymouth, turned over for two or three seconds for warm starts and well over 5 seconds for cold starts. Cars have come a long way.

 

[REWahoo]

One way to defeat the start-stop system is to drive with the heater turned up on a very cold day. The demand for passenger warmth keeps the engine running at most stops.

Does having the AC on do the same?

 

[Chuckanut]

Does having the AC on do the same?

My understanding is that the car's computer would most likely keep the AC compressor from running during cold weather when it is not needed. The only exception would be for defogging a window.

FWIW, I am under the impression that even on a hot day the computer will temporarily turn off the compressor, if, for example, a burst of power is needed going up a steep hill or when passing at near full throttle. I remember my father turning the AC off back in the old days when climbing hills or passing several cars at once.

 

[REWahoo]

My understanding is that the car's computer would most likely keep the AC compressor from running during cold weather when it is not needed. The only exception would be for defogging a window.

FWIW, I am under the impression that even on a hot day the computer will temporarily turn off the compressor, if, for example, a burst of power is needed going up a steep hill or when passing at near full throttle. I remember my father turning the AC off back in the old days when climbing hills or passing several cars at once.

That may be accurate information regarding starting or stopping the compressor, but what I want to know is will having the AC on do the same as having the heat on as you describe - defeat the start-stop [engine] system.

 

[RunningBum]

My understanding is that the car's computer would most likely keep the AC compressor from running during cold weather when it is not needed. The only exception would be for defogging a window.

FWIW, I am under the impression that even on a hot day the computer will temporarily turn off the compressor, if, for example, a burst of power is needed going up a steep hill or when passing at near full throttle. I remember my father turning the AC off back in the old days when climbing hills or passing several cars at once.

I think REW is asking if the AC on a hot day will override start/stop. If he's not asking that, I am.

btw, I still turn the AC off when I'm climbing a long hill--3+ miles, 2000" ft is my usual. Is that not necessary anymore? Fairly current car--2014 Forester. I can check again this summer, but it seems like cool air is blowing. I don't usually hammer the uphill but I don't baby it either.

 

[marko]

One way to defeat the start-stop system is to drive with the heater turned up on a very cold day. The demand for passenger warmth keeps the engine running at most stops.

Some cars (ours do) have a button you can hit to turn off the function.

 

[misanman]

Yes, I think the best way to defeat it is to hit the "off" button.

 

[Chuckanut]

That may be accurate information regarding starting or stopping the compressor, but what I want to know is will having the AC on do the same as having the heat on as you describe - defeat the start-stop [engine] system.

IIRC, the compressor runs on an electric motor not a belt on my hybrid. So, there would be no reason to keep the engine running for short stops.

 

[mystang52]

Yes, I think the best way to defeat it is to hit the "off" button.

My 2018 Audi Q5 has the start-stop; this car replaced my 2014 Q5 (accident) that did not have it. My gas mileage is significantly better now. I barely notice when the engine kicks off.

I use the Off button when I drive in Manhattan, and some other stop and go traffic situations. But once the car is shut off, when it restarts it will default to having the start-stop back on. I believe this applies to all makes.
And as alluded to by others, supposedly the starters on cars with start-stop are specially designed for this feature.

 

[COcheesehead]

My wife hates it. I love it. I think if you pay attention to it, it will drive you bonkers. If you just drive and don't think about it, it's not a big deal. I was told it adds about 2 miles more per gallon. Your results may vary.

 

[travelover]

I liked it on my Escape hybrid, but it launched on electrical power so there was no lag. I disabled it on my Highlander with an after market device that makes it default to disabled, but I can still turn it on with the original control button. On most cars with automatic transmissions that also have a manual mode, driving in the manual mode disables the auto stop/start.

 

[Sunset]

..... I remember my father turning the AC off back in the old days when climbing hills or passing several cars at once.

I did that with my 4 cylinder cars, they didn't have turbos or anything, so it would really help "boost" the performance.

 

[DanP]

Having the AC on will prevent it on some makes, not all.

Like many on this forum I grew up with cars that were not always quick or easy to start, which makes it mentally bothersome when waiting to make a left turn on a busy street.

 

[PatrickA5]

Does having the AC on do the same?

I have a 2018 Honda Pilot with the stop/start "feature". I hate it and turn it off, but for some reason there is no way to permanently turn it off. I have to do it each time I start the car.

To answer the question, the start/stop feature does not work with the AC on (at least in my car). There's a long list of things that will cause the feature to not activate. I haven't notice yet if the heater does the same thing.

 

[ExFlyBoy5]

My "new to me" F150 has the feature and I disliked it. Like other posters, you can use an "off" switch, but it will reset when you shut off the vehicle. But, like someone else here, I have a program in which I can "hack" the system to permanently disable the feature...as well as enable/disable many other items on the vehicle. The technology (and ability to hack it) is really fascinating to me.

 

[FUEGO]

I had it on a little tiny Audi I rented in Europe and it was awesome. I have no clue what the gas mileage was since it was in liters per km but I didn't spend much on gas in spite of driving up and down the Alps quite a bit

It didn't bother me a bit, and seems to make perfect sense. I wish I had it on my current car here in Raleigh because a lot of the traffic signals on the main road bordering my neighborhood take 3+ minutes to complete a cycle.

 

[braumeister]

Every once in a while I happen to notice the engine shutting off while sitting at a traffic light. But in a PHEV, there is never a noticeable lag since the electric motor reacts instantly when I step on the accelerator. One of the many benefits of the hybrid.

 

[travelover]

My "new to me" F150 has the feature and I disliked it. Like other posters, you can use an "off" switch, but it will reset when you shut off the vehicle. But, like someone else here, I have a program in which I can "hack" the system to permanently disable the feature...as well as enable/disable many other items on the vehicle. The technology (and ability to hack it) is really fascinating to me.

I believe that on the F150 it is off when you have a trailer attached. Some people plug a trailer test light into the trailer light plug to disable the start/ stop function.

 

[Scrapr]

My new(ish) Volvo has it and I tolerate it. There is a noticeable clunk when it kicks in. If it was a hybrid the battery would take care of that part and it would smooth out the ride. I drive dfferently than in the company prius. With the Volvo I watch traffic if turning left and take my foot off the brake (restarting the car0 a second or so before I'm going to pull out/turn

About my only complaint

 

[Closet_Gamer]

I've had it on loaner cars from the dealer when my car is getting service. I loathe it.

 

[kite_rider]

It's on my 2018 GMC Terrain, and I have the Diesel engine. I'm impressed with how fast it fires up the engine and gets you going. Seems to be active with the A/C on in the summer and with the heater on in winter. There is no way to turn it off.

Many guest passengers have asked me if the car is a Hybrid when it shuts off and on. It's not...