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

[racerzz]

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

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[bgn]

The truck needs a lot of power for the electric power steering and it thinks you're wanting to move.

 

[racerzz]

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.

 

[bighap]

Keep turning your shifter clockwise if you need something to fidget with while at a light.

 

[Timothyd]

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

Why are you doing that? Just wearing the tires.

 

[racerzz]

Not wearing the tires because it is not necessary to move them. All that is needed is to move just past free play, as soon as any resistance is encountered the engine starts and will continue to run. Weather used or not it seems like a strange feature.

 

[matmondro]

The truck sees steering input in this situation in the same way it sees you lifting your foot off the brake. It's a trigger to start the engine because it's programmed to think you're wanting to drive when you start moving the steering wheel.

 

[Blue_Max]

Not wearing the tires because it is not necessary to move them. All that is needed is to move just past free play, as soon as any resistance is encountered the engine starts and will continue to run. Weather used or not it seems like a strange feature.

Reminds me of Henny Youngman. "I told my doctor it hurts when I do this. The doctor said, 'Don't do that.'"

 

[Pointyears]

Reminds me of Henny Youngman. "I told my doctor it hurts when I do this. The doctor said, 'Don't do that.'"

Dad, is that you?

 

[MavStangVa]

Reminds me of Henny Youngman. "I told my doctor it hurts when I do this. The doctor said, 'Don't do that.'"

I recall either him or maybe Red Skelton saying he went to a doctor because he broke his arm in 3 places and the doctor said "stay out of those places."

 

[MavStangVa]

Not wearing the tires because it is not necessary to move them. All that is needed is to move just past free play, as soon as any resistance is encountered the engine starts and will continue to run. Weather used or not it seems like a strange feature.

So you want a 40k vehicle to have the AI capability to KNOW when you are actually trying to turn versus just moving the steering wheel for no reason? I realize we think these trucks are technological marvels but in reality the computer works like any industrial type control, an input triggers the software to activate an output. It doesn't know you aren't trying to turn left or right. It just knows you moved the wheel triggering the input. Since the steering is electrical power it triggers the output to start the engine to provide electrical power to the steering which likely does NOT operate off of the battery but off of the alternator.

 

[Cancunbadlands]

When you turn the wheel, you are asking the car for steering assistance. Providing enough torque to move the wheels while the car is stationary requires a massive draw of electrical current.

To prevent draining the battery or leaving the driver with "heavy" manual steering in a potential emergency, the Engine Control Unit (ECU) interprets that movement as a signal that the driver is preparing to move or needs control, immediately firing up the engine to provide full power.

 

[Timothyd]

Not wearing the tires because it is not necessary to move them. All that is needed is to move just past free play, as soon as any resistance is encountered the engine starts and will continue to run. Weather used or not it seems like a strange feature.

Look at the pavement after you turn the wheels without the vehicle moving. You'll see tire material there on the pavement from the friction. That's wearing

 

[racerzz]

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.

 

[dalola]

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.

A man of your pedigree shouldn't be asking such silly questions, especially when you already knew the answer.

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