Push Starting a Newer Car

[RonD]

1 wire alternators use an internal "RPM" switch to Turn On vs a Battery Light(key on) switch
So they have a minimum RPM trigger to activate
You should also install a "key on" Volt Meter so you can monitor alternator output voltage at idle, you may need to adjust the alternators pulley size so it stays above the minimum level at idle

 

[-Nate]

Thanx for all the good replies here ! .

Somehow they wound up in my SPAM folder until today (Sat. 9.3.22) .

Older alternators and generators had "residual magnetism" that meant as soon as it spun fast enough it would begin to charge so push/pop/bump starting some vehicles is possible in spite of a funny dead battery .

 

[Chapap]

I had a 2016 Camaro (push button start) and asked the Camaro forum the same thing. The response was a solid "no." I don't think it's possible period... computers and all that.

 

[19Walt93]

I have roll started my '93 Ranger with electric fuel pump, electronic fuel injection and a dead battery many times....

Keep in mind that's EEC IV, not OBD II. No power to the PCM means no injector firing and no spark. Why didn't you fix it after the first time??

 

[tinman_72]

My original statement was made in response to a statement that said nothing about OBD II. It just said "that wouldn't work on a car with an electric fuel pump, electronic fuel injection, and a stone dead battery.
Why didn't I fix it? I did. I replaced the battery. But batteries only last 4-7 years. I have had the truck since 1994, you do the math.

 

[-Nate]

?!? MATH ?!? you mean I hafta take my SHOES OFF ??!! .

 

[4x4junkie]

Newer Tacoma trucks can be push-started... 2018 for sure, and probably newer too since the drivetrains haven't changed.

A friend had a Mustang (2019, I think?) who said he tried to push start it out of simple curiosity and it failed to start. He's not very technically savvy though so it wasn't clear whether it's not push-start-able or if he didn't do something right (it had push-button start).

Not being able to push-start removes the classic fall-back to getting going again should you leave the lights on, fall asleep with the radio on, or the battery just simply goes kaput with age and you're unable to start the car normally.
(or is it, if the battery is too weak to crank the engine in a push-button-start car and it fails to start, will the ignition remain on after the failure? If it does, would the car then be push-startable?)

 

[RonD]

There are a few issues going on with push starting manual transmission vehicles

As said there "may" be enough residual magnetic force left in the alternator's rotor to generate enough voltage to "wake up" the dash and computer so alternator can continue to increase electrical production to 14volts
But any "Startup Voltage" can also be absorbed by bad battery, so no dash lights would come on and no start
If you have dash lights, even dim, with key on, then you should be able to push start vehicle

Latest models may have keyless transponder, so the vehicles computer/receiver must have at least enough voltage available to recognize correct transponder code so it can at least turn on the system, which requires even more voltage, but if there are dim dash lights it should push/roll start
You could try a long rolling push start and hope alternator had enough residual magnetic force to overcome dead battery and then dash would come on once keyless transponder was recognized and then spark and fuel once computer fully boot up and saw the crank sensor timing pulse
A lot of "ifs", lol


Alternators generate a magnet field in the rotor using voltage, creates an electro-magnet, as the rotor spins the electro-magnet's field interacts with the 3 Field coils in the alternator's case and they generate a higher AC voltage which is then converted to DC

A generator uses permanent magnets in its case, and as the rotor spins, the Rotor generates electricity
So opposite of the way alternator generates electricity
But a Generator can start generating electricity just by spinning it because if has permanent magnets, it doesn't use electro-magnets like alternator

That's why the reference to "residual magnetic force" for alternator and push starting
If you continually use a piece of metal as an electro-magnet it will retain some "residual magnetism", but, in the alternator's rotors case, its also surrounded, and connected to lots of metal parts that dissipate the magnetism so wouldn't count it generating current without any voltage being put in the rotor first

 

[NoRangerDude]

I've bump started my 2017 Fiesta ST pushbutton start with a dead battery. I rolled it down a hill and dumped the clutch in 2nd gear.