Why turning the steering wheel slightly will restart the engine after stop start has shut it off?

[MavStangVa]

ok, a bit of background. I am a 69 year old retired professional mechanic, 8 ASE certs, can inspect anything that rolls in NYS, top technician award from US Suzuki, award for the motorcycle road racer I built. Successfully built and flew a small kit plane. Competed in both MX and road racing with motorcycled and auto cross and hpde/time attack with autos. I understand automotive electrical systems, the battery is a storage device which is replenished by the charging system. The alternator could never provide the high amperage needs of the starter or any other high amperage device on the car. We had diesel trucks at work that needed 100 amps just to operate the intake heater, alternators were 100 amps or less, Solution? two or three batteries to provide instant amperage which would then be relatively slowly recharged by the alternator. I can accept that the truck is viewing the steering load as a reason to start but I also think it is a programming weak point. Should be a combination of brake and throttle input compared to steering angle. The argument that the alternator has to come on line to provide energy for the PS motor simply makes no sense as the battery is a vast reservoir of stored energy. If the battery could not supply the amperage needed for the power steering we would never be able to start the engine as the starter is a massive amperage draw.

So how long until that battery drains too far to restart the engine? Maybe, just maybe the engineers looked at worst case scenarios and LEGAL implications when designing this system. Not an issue for me since I turn off ASS before I leave the driveway. Why? Because on 2 occasions before the Maverick I have had to accelerate and turn left to avoid a speeding semi that was oblivious to stopped traffic. Both times the vehicle in front of me was rear ended. I want the truck ON when I am in it.

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[matmondro]

FWIW too, steering angle is already a parameter factored into the ECMs decision to activate start-stop. If you come to a stop and the angle is past a certain degree, the truck will not shut off.

 

[kevinmccune]

A friendly sales person deactivated mine for$(40) used a laptop,he said the voltage drop coming to idle is what triggered the stop circuit he had to adjust twice( never been bothered with that garbage since,now if I could disconnect the traction control and probably the stability racket,I constantly had to fumble for the so called traction control" to cut it off so I could get somewhere in the sleet and ice storm,when you call for power you need it to turn the wheels over,that thing that constantly bogs the engine out will keep you stuck,I grew up the country driving old ford one wheel drive pickups after awhile you learn how to drive in the slick( worst case scenario you install chains)

 

[Pointyears]

ok, a bit of background. I am a 69 year old retired professional mechanic, 8 ASE certs, can inspect anything that rolls in NYS, top technician award from US Suzuki, award for the motorcycle road racer I built. Successfully built and flew a small kit plane. Competed in both MX and road racing with motorcycled and auto cross and hpde/time attack with autos. I understand automotive electrical systems, the battery is a storage device which is replenished by the charging system. The alternator could never provide the high amperage needs of the starter or any other high amperage device on the car. We had diesel trucks at work that needed 100 amps just to operate the intake heater, alternators were 100 amps or less, Solution? two or three batteries to provide instant amperage which would then be relatively slowly recharged by the alternator. I can accept that the truck is viewing the steering load as a reason to start but I also think it is a programming weak point. Should be a combination of brake and throttle input compared to steering angle. The argument that the alternator has to come on line to provide energy for the PS motor simply makes no sense as the battery is a vast reservoir of stored energy. If the battery could not supply the amperage needed for the power steering we would never be able to start the engine as the starter is a massive amperage draw.

Buyers would object more if they need engine power and it's not available, rather than not wanting it like you. To hit the sweet spot, the vehicle would have to be psychic.

 

[Cancunbadlands]

A friendly sales person deactivated mine for$(40) used a laptop,he said the voltage drop coming to idle is what triggered the stop circuit he had to adjust twice( never been bothered with that garbage since,now if I could disconnect the traction control and probably the stability racket,I constantly had to fumble for the so called traction control" to cut it off so I could get somewhere in the sleet and ice storm,when you call for power you need it to turn the wheels over,that thing that constantly bogs the engine out will keep you stuck,I grew up the country driving old ford one wheel drive pickups after awhile you learn how to drive in the slick( worst case scenario you install chains)

You could do it for free using ForScan

 

[BobC]

Can't really accept that as the starter is generally the highest amperage draw and a healthy battery can easily handle that. Also, once started by turning the wheel the engine will continue to run until accelerating away from the stop.

Probably a normal condition. If stopped with auto-stop, by letting up on the brake pedal, the engine will also restart. Another auto-stop solution is to take short drives and let the battery get to a less than 75% charge level, then the auto-stop function won't work.

 

[BobC]

So how long until that battery drains too far to restart the engine? Maybe, just maybe the engineers looked at worst case scenarios and LEGAL implications when designing this system. Not an issue for me since I turn off ASS before I leave the driveway. Why? Because on 2 occasions before the Maverick I have had to accelerate and turn left to avoid a speeding semi that was oblivious to stopped traffic. Both times the vehicle in front of me was rear ended. I want the truck ON when I am in it.

I am not qualified to answer that, as there are so many variables that can affect the battery condition (weather conditions). I'm just now learning about some of the on my '23 Lariat, 35K mi. If accessory items are on, e.g., seat/steering wheel heater, defroster, side mirror heater, Bluetooth, updates, and others, they may draw current during operation or when shut off. I'll be scheduling a battery drain test with the local dealer. The hybrid models have a TSB oiut I think, on some of these issues.

 

[racerzz]

I am not opposed to driver aids in general I simply believe they should be an option. Of course stop start is meant as a fuel saver but I doubt its long term value. I am less concerned with starter wear than I am with the repeated drop of oil pressure.

 

[Blue_Max]

I am not opposed to driver aids in general I simply believe they should be an option. Of course stop start is meant as a fuel saver but I doubt its long term value. I am less concerned with starter wear than I am with the repeated drop of oil pressure.

Then be sure to disable it on startup! That's what I do. It's almost as ingrained as turning the key.

 

[racerzz]

Because I drive almost exclusively in sport mode, I am making seven or eight selections every time I start the truck. I paid for the truck, I drive the truck, seems like I should have the option to set it up the way I want to use it. If I am out doing errands I have to go thru the same sequence at every stop. I just want the option to set the parameters for my driving style and not have them constantly default to some preconceived notion of how I should drive.

 

[HeyBales]

I am not opposed to driver aids in general I simply believe they should be an option. Of course stop start is meant as a fuel saver but I doubt its long term value. I am less concerned with starter wear than I am with the repeated drop of oil pressure.

Actually more for smog control than fuel savings.

Also - your battery could be at the line of too low, perhaps why ICE restarts and keeps running.
The steering power requests drops voltage below the line, it keeps running to get above the required range.
That would be a good test at home, unless you already this.
Tug on steering to get ICE going - don't actually take off, how long does it actually keep going?

Not sure if noticed yet, but didn't see it quoted yet.

AUTO-START-STOP – FREQUENTLY ASKED QUESTIONS

Why does the engine not always stop when I expect it to?
The system is designed to work in a way that complements other vehicle systems, allowing them to operate at optimum performance.
The system does not stop the engine if:

• The driver door is open.
• Your vehicle is at high altitude.
• The heated windshield is on.
• The engine is warming up.
• The outside temperature is too low or too high.
• The battery charge is low.
• The battery temperature is outside the optimal operating range.
• The engine is required to run to maintain interior climate and reduce fogging.

Why does the engine sometimes restart when I do not expect it to?
The system is designed to work in a way that complements other vehicle systems, allowing them to operate at optimum performance.
The system restarts the engine if:

• You switch the heated windshield on.
• You switch maximum defrost on.
• Your vehicle starts to roll downhill in neutral.
• The engine is required to run to maintain adequate brake system assistance.
• The engine is required to run to maintain interior climate and reduce fogging.

Can I permanently switch the system off?
No.The system plays an important role in reducing the fuel consumption and the CO2 emissions.

 

[HeyBales]

Because I drive almost exclusively in sport mode, I am making seven or eight selections every time I start the truck. I paid for the truck, I drive the truck, seems like I should have the option to set it up the way I want to use it. If I am out doing errands I have to go thru the same sequence at every stop. I just want the option to set the parameters for my driving style and not have them constantly default to some preconceived notion of how I should drive.

You'll find other threads pointing out that if the emissions and CAFE test results were done with specific truck settings to obtain them - those are required to be the default. every. single. time.

 

[MavStangVa]

Because I drive almost exclusively in sport mode, I am making seven or eight selections every time I start the truck. I paid for the truck, I drive the truck, seems like I should have the option to set it up the way I want to use it. If I am out doing errands I have to go thru the same sequence at every stop. I just want the option to set the parameters for my driving style and not have them constantly default to some preconceived notion of how I should drive.

You want a "custom" for you truck at a mass production price. Imagine the cost if every buyer had to list every feature they wanted then Ford built that truck to their specifications. Humm, I recall Buick did that back in the day and Henry showed how to achieve mass sales and profit. You can buy a car built exactly how you want it but not for under 40k . as to you paid for the truck then YOU can alter it to be what you want. Ford won't sue you over it.

 

[racerzz]

Never actually sat and waited to see if it would eventually shut down again but so far it never has waiting for a typical light. I have not experimented with it much as I only play with it when forgetting to turn it off. I have a Mazda I bought new 18 years ago, manual trans no driver aids other than ABS, such a pleasure to drive.

 

[Cherokee]

Can anyone explain the logic as to why turning the steering wheel slightly will restart the engine after stop start has shut it off?

My 2924 Lariat restarts instantly if I,
Turn on the A/C,
Turn on the heat,
Roll down a window or two.
Or turn the steering wheel.
All normal.

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