Autoidle then wont restart

[noguermunky]

Hello all,
Twice in the past month I have encountered my 2018 GT2 go into auto-idle at a stop light then the engine would not restart. After the first instance I was able to jump start the car, and thereafter I had battery and alternator checked but both tested fine. Car started and ran as expected for close to a month (daily driver) but then it happened again. Again, I was able to jump start car but now unsure as to best path forward to ID the root issue. Has anyone ever experienced this before? Apologies if this is a repost, I am new here and could not find a search button for possible previous thread on same issue!

 

[Snicklefritz]

It sounds like you are talking about Idle Stop Go ISG. "Auto-idle" isn't a descriptor that I've read before. If ISG shuts down your engine and when you get off the brake and push the gas it doesn't come back on, that is a failure of the system and I have not read of it before either. Until you can have it checked out, I suggest turning ISG OFF each time you drive so this can't happen in the meantime.

 

[rtv900]

need a way better description
Do you mean when you release the brake it cranks but never starts?
Or do you mean it just sits there and does nothing at all?
And if you then put it in Park, are you saying it will not start normally in that case?

But you say you could "jump it"???? So does that mean it acts like a dead battery with a super slow crank or no crank at all? But starts when hooked up to another battery?
But then I'm assuming when you start it initially first thing in the morning it does start fine the first time? If you just disable the feature can you park and restart the car like normal or is that a problem too?
so many questions

 

[D.J.]

Hello all,
Twice in the past month I have encountered my 2018 GT2 go into auto-idle at a stop light then the engine would not restart. After the first instance I was able to jump start the car, and thereafter I had battery and alternator checked but both tested fine. Car started and ran as expected for close to a month (daily driver) but then it happened again. Again, I was able to jump start car but now unsure as to best path forward to ID the root issue. Has anyone ever experienced this before? Apologies if this is a repost, I am new here and could not find a search button for possible previous thread on same issue!

From the limited information, if your car won't start on it's own, but will start with a boost - it is almost certainly a dead, or weak battery.

If you could post a video of the car trying to start without a boost, and then starting with a boost, we could be much more confident.

 

[Ah GetFd]

Go for simple obvious things.

Replace the battery. Unless it's brand new, if it's got three to four years use it's reaching end of life.

Probably what is happening......

The battery has a shorted plate. This break is caused by normal corrosion which is end of life for all lead acid batteries.

Whilst the full voltage is applied across the battery terminals by the alternator, there may only be 5 x 2 volt plates rather than six.

So when the charge voltage from the alternator disappears the battery reverts to 10 volts and less when it comes to crank which is insufficient to turn the starter. This explains why you can jump start the car with a good battery. This explains why the car will keep running once started because the alternator does the work of supplying all electrics plus....recharging the battery.

When you park the car however, characteristics of all lead acid batteries is they recover charge due to chemical reaction.

So this explains why anyone can crank their car until the battery discharges and will no longer turn the starter motor, but come back 10 minutes later and you can repeat the process.

Replace the battery.

 

[D.J.]

Go for simple obvious things.

Replace the battery. Unless it's brand new, if it's got three to four years use it's reaching end of life.

Probably what is happening......

The battery has a shorted plate. This break is caused by normal corrosion which is end of life for all lead acid batteries.

Whilst the full voltage is applied across the battery terminals by the alternator, there may only be 5 x 2 volt plates rather than six.

So when the charge voltage from the alternator disappears the battery reverts to 10 volts and less when it comes to crank which is insufficient to turn the starter. This explains why you can jump start the car with a good battery. This explains why the car will keep running once started because the alternator does the work of supplying all electrics plus....recharging the battery.

When you park the car however, characteristics of all lead acid batteries is they recover charge due to chemical reaction.

So this explains why anyone can crank their car until the battery discharges and will no longer turn the starter motor, but come back 10 minutes later and you can repeat the process.

Replace the battery.

But that wouldn't explain why this battery apparently tested fine when it was tested! Presumably with an electronic tester that checks for voltage and internal resistance.

and thereafter I had battery and alternator checked but both tested fine.

 

[Ah GetFd]

But that wouldn't explain why this battery apparently tested fine when it was tested! Presumably with an electronic tester that checks for voltage and internal resistance.

Roadside tests at a battery mob whose job it is to sell you a new battery don't tell you much.

Put it in a lab, heat it up, cool it down, do a heavy discharge, a light discharge, recharge it with a shallow charge, a boost charge, then tear it down and find everything from sulphation to a broken plate to a break in a plate that opens and closes providing intermittent failure to a poor weld to well you name it.

It's the cheapest option and, you get a new battery!

And I will just add to this that if stop/go adds to this problem of a failed battery then it is a damned stupid idea in the first place. Many months ago I posted on this fact. I am not sure if stop/go does a restart from the battery as stop/go is not a feature on Australian delivered Stingers. If it was I wouldn't have bought it and I checked in the showroom at the time. Nope. No stop start feature on MY23 Stinger, the last model produced.

I had recently bought a Mazda that did have it BUT it uses the compression of the motor to restart it after stopping at say a red light.

To use a battery though......being in the outside lane stopped at a red light in an 80kmh zone. The light goes green, you are stopped for some time and eventually someone cleans you up doing 80kmh...........(50 mph).

Lead acid batteries go through sudden death. The constant restarting causes a recharge current each time. Charging current is what destroys the positive plate, the standard failure mechanism of all lead acid batteries.
So rather than doing one start to drive to work and another to drive home you are doing 40, 50 starts a day, makes no sense.

The scenario is this.....
Your battery is fine. The high starting current starts your car and you drive off. That same current breaks the already corroded plate so that the NEXT time you come to start the car, the plate is already broken. That's the sudden death part.

That's why for example. Nickel Cadmium is used in Power Stations. Nickel Cadmium does not go through sudden death................no surprises.

 

[rtv900]

I push the button to turn that feature off immediately upon starting my car.
It's muscle memory now.