Car stalls during idle after battery replacement, then fine after two days

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Replacing a car battery can lead to temporary stalling issues due to the engine control unit (ECU) needing time to recalibrate its fuel-air-timing settings after disconnection. This stalling may resolve itself after a few days as the ECU relearns optimal settings during idle. Different vehicles respond uniquely to battery replacements, and without specific make and model information, diagnosing the issue can be challenging. Concerns were raised about the reliability of modern vehicle software and the longevity of internal combustion engines compared to older models. Overall, if the car is running well after a few days, it is likely that the issue has been resolved.
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This question for any technical purposes is way out-of-my league.
How or why is it that replacing a dead car battery with a new battery would allow the car to stall while engine idling for 1, maybe 2 days, and then no further stalling after that? This should seem to make no sense. Typical modern car by well-known foreign manufacturer. Fuel-injected, in case that were important.
 
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Maybe the ECU forgot its fuel-air-timing settings while the battery was removed. It will work them out again, given time idling, and has now learnt them again.

What make, model, and year, is the car?
 
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Software. A reliable RTOS is a myth ASFAIK. The exception is if it cost as much as what they put in an F-18 and such. We simply don't pay enough to get really good SW in our cars.
 
Servicing cars with airbags requires disconnecting the battery. Different cars respond in different ways after a battery disconnect. Without knowing the make, model, and year, we cannot be specific in the diagnosis.
It is usually a case of telling the owner: "That light will stay on, until you get halfway home".
 
Baluncore said:
Maybe the ECU forgot its fuel-air-timing settings while the battery was removed. It will work them out again, given time idling, and has now learnt them again.
Yup, happened to me once. It's incredibly difficult to drive a manual transmission if you have to keep one foot on the gas all the time to avoid stalling.
 
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symbolipoint said:
Typical modern car by well-known foreign manufacturer.
In Canada, where I live, all cars are foreign. :wink:
 
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russ_watters said:
It's incredibly difficult to drive a manual transmission if you have to keep one foot on the gas all the time to avoid stalling.
That is why I prefer diesels with a hand throttle, without a computer.
 
I would also favor the ECU, but some crud on the cable to the battery can do the same thing, until it is better seated.
 
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Baluncore said:
That is why I prefer diesels with a hand throttle, without a computer.

I prefer cars that don't stall. A hand throttle would make it harder to text and/or eat at the same time.
 
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  • #11
Diesels have a governor as part of the injection pump. The "RPM pedal" or the hand throttle sets the required RPM, which stays where you set it. The diesel has plenty of torque and will not stall. When you get to a hill, it injects more fuel to maintain the RPM and road speed. That is the original cruise control.
 
  • #12
Baluncore said:
Diesels have a governor as part of the injection pump. The "RPM pedal" or the hand throttle sets the required RPM, which stays where you set it. The diesel has plenty of torque and will not stall. When you get to a hill, it injects more fuel to maintain the RPM and road speed. That is the original cruise control.
Maybe in your corner of the world but not in the USA. If I drove a vehicle like that here in the US I would think someone pulled an engine out of a tractor or industrial machine and put in a vehicle without changing the pump. The old mechanical pumps here would have a governed top speed as well as bottom. After that it's whatever your foot says.
 
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Baluncore said:
Diesels have a governor as part of the injection pump. The "RPM pedal" or the hand throttle sets the required RPM, which stays where you set it. The diesel has plenty of torque and will not stall. When you get to a hill, it injects more fuel to maintain the RPM and road speed. That is the original cruise control.

Interesting. I have nothing against diesel technology per se. It's more of a sense that they tend to be available primarily in larger vehicles which doesn't fit my needs.

I'm mostly bummed that manual transmissions are disappearing and automation is increasing. So I'm trying to keep my 30 year old car running as long as I can. It has some issues but stalling is not one of them. I wouldn't tolerate that. Who would?
 
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Averagesupernova said:
Maybe in your corner of the world but not in the USA.
You have my sympathy.

The disposable diesel engines built for cars today are as bad as the petrol engines. Not only do they have an ECU that needs to know the calibration number of each injector, but they fail just as quickly, and cannot be reconditioned.

When they first introduced stepped timing belts, those belts were reliable, but were quickly reduced to needing replacement before 100,000 km. Timing chains are now the same gauge as bicycle chains, so they wear, stretch and destroy interference engines, that then require the disposal and replacement of the whole vehicle.

Today, a horse lives for more than twice as long as a car, plus it runs on renewable energy, and self replicates. Horses are self-driving, and come with an intelligent controller in their head that avoids stupid collisions.

The IC engines, in the cars being built today, have a lifetime that is less than a dog. My old truck has seen out two dogs already, and will see at least another dog out with me.
 
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  • #15
[THREAD HIJACKING]
Baluncore said:
Today, a horse lives for more than twice as long as a car, plus it runs on renewable energy, and self replicates. Horses are self-driving, and come with an intelligent controller in their head that avoids stupid collisions.
... and they poop everywhere ... 8 tons per year ... for every horse ... whether you use them or not. You need 3 months to a year to compost it. (So, between 2 and 8 tons of manure lying around at all times... per horse.)

Assuming - conservatively - that we need 1 acre of land to feed a horse and get rid of its manure, and that we replace each car in the US with a single horse (forget speeds above 30 km/h), we need 290 million acres of farmland; there are about 900 million acres of farmland in the US right now.

how-many-cars-US-800x560-1.png

Horses were a nightmare for modern life - 100 years ago - until the invention of cars. I can't imagine how bad it would be today.

There is no easy way out. Maybe we should review the need for our desperate thirst for transportation.
[/THREAD HIJACKING]
 
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  • #16
Horse manure is not a problem to be rid of, it is an asset that is needed to fertilise and improve the organic structure of the soil that we grow our food in.

Public transport works well in Europe and Japan, so why do people in the USA require so many cars to commute?

I am not suggesting each car should be replaced with a horse, just that a horse is a small investment over 30-years, while a car costs more up front, yet lasts only 10-years. I do realise that horse transport will not return, because they use insufficient fossil fuel to support the US economy.
 
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  • #17
@Baluncore I don't know what any of that has to do with a mechanical injection pump with a low RPM limit as well as a top limit on the governor. Before diesel engines went electronic the only thing the governor inside the pump did was limit each end. The driver regulated speed the same as any other vehicle. If the driver had their foot into the pedal by a certain amount then the engine would meter that amount of fuel in no matter the load. Nowhere in the USA does any diesel engine that propels a vehicle down the road at highway speed govern the RPM as set by a lever. The driver is the governor. If you are talking about cruise control on diesels that is a different matter.
 
  • #18
you gave very limited information but in general terms
The car’s diagnostics would reset after two twenty-minute trips after the car’s battery is reconnected. This is The ambiguous car "computer" does “relearning” how to run. Generally the car’s computer will adjust various inputs to maximize the engine’s ability to run well. Not a total answer but a guess as to your current conditions. If it now runs good, you should be ok.
 
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  • #19
@Averagesupernova The mechanical fuel pumps with a centrifugal governor have an idle speed setting. The top engine RPM is not set, but there is a maximum fuel setting, (to prevent black smoke). Those settings are screw adjustable on the pump.

The accelerator pedal, coupled with the hand throttle, sets the wanted RPM, that is then compared mechanically in the governor with the actual engine RPM, and the fuel is increased or reduced to match those two. The mechanical control loop is damped in a bath of diesel or lube oil. Full depression of the accelerator injects maximum fuel without governor control.
Averagesupernova said:
Nowhere in the USA does any diesel engine that propels a vehicle down the road at highway speed govern the RPM as set by a lever.
That is not true for many trucks with mechanical injection pumps. Look at the older diesel Toyota Hi-Lux and Land Cruisers. The driver depresses the accelerator pedal to hold the speed they want, they can then set the hand throttle to clamp the accelerator linkage, the governor will then hold that RPM, while the pedal stays where it was before the foot was lifted off.

Diesels today are more petrol-like in their response, and are often fitted with a turbocharger. Normally aspirated diesels use a compression ratio of about 20:1, while those with turbos use about 16:1, (sufficient to start). The turboboost on a 16:1 engine can push the power output and cylinder pressures beyond what is reliable. That shortens the life of the engine if it is used often.

Common rail fuel injection is now needed to meet emission control regulations, so mechanical governors have been replaced with an ECU and software cruise control. The governor is now in the software, the programming of the accelerator pedal position can be for speed or acceleration.
 
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  • #20
I will agree with Baluncore on all the above except for the lever part. My Dodge Diesel Cummins, no lever but had cruise , had 16:1 turbo ( 2001 model) . Had 220,000 miles on it and excellent compression, all indications that it could go to 500,000 miles before a valve job. Love those Cummins.
 
  • #21
The hand throttle on a tractor was usually a lever. I only see older tractors.

On a road vehicle, it is often a rotary knob that turns a screw on the end of a cable. If you hit the knob, there is a quick release that takes the engine speed setting to idle. A round knob is safer than a lever in an MVA.
 
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Baluncore said:
Horse manure is not a problem to be rid of
Depends on where on the internet you visit.
 
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  • #23
Baluncore said:
Look at the older diesel Toyota Hi-Lux and Land Cruisers. The driver depresses the accelerator pedal to hold the speed they want, they can then set the hand throttle to clamp the accelerator linkage, the governor will then hold that RPM, while the pedal stays where it was before the foot was lifted off.
I've never driven one. I seriously doubt that setup is legal in the USA. The only thing I've seen on diesels that holds the throttle control mechanically is on semi tractors that is used during warm up. As the motor warms up the RPM creeps up and the driver backs it off. It is not meant to be used as a cruise control.
 
  • #24
Baluncore said:
The hand throttle on a tractor was usually a lever. I only see older tractors.

On a road vehicle, it is often a rotary knob that turns a screw on the end of a cable. If you hit the knob, there is a quick release that takes the engine speed setting to idle. A round knob is safer than a lever in an MVA.
Yes. This is exactly what I am referring to on a semi tractor. Turn the knob counter clockwise to increase the throttle. Clockwise to decrease or push the button on the center of the knob to completely release and go back to idle. Not meant to be used as a cruise control. Gas rigs had them too. Usually to increase idle to run a hydraulic pump coming off the PTO on the transmission or maybe an air compressor.
 
  • #25
#18 from @Ranger Mike is about as good a summary as can be given, for me o.p. who asked. Some but not all other comments are going in several different directions. The repair technician could have but did not instruct us about this; which would have been nice.
 
  • #26
We do not know the make, model and year.
Different vehicles behave in different ways.
 
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Baluncore said:
The driver depresses the accelerator pedal to hold the speed they want, they can then set the hand throttle to clamp the accelerator linkage, the governor will then hold that RPM, while the pedal stays where it was before the foot was lifted off.
So to make sure I have this right one last time you are telling me that the governor in a diesel road vehicle is made to 'hold RPM'? Sorry, I've driven enough diesels from trucks with mechanical pumps pulling 40 tons as well as lighter vehicles with mechanical pumps to know this is not true. Imagine an automatic transmission shifting with an engine in front of it governed to hold RPM. Telling a diesel pump shop that you want your pump set up to do that and they'll tell you to hit the bricks.
 
  • #29
Averagesupernova said:
Imagine an automatic transmission shifting with an engine in front of it governed to hold RPM.
It would be terrible, which is why it uses a manual transmission.

Luckily, the rest of the world was not like the USA.
Here, we knew how to use a clutch and how to change gear, so we did not need automatic transmissions, with inefficient torque converters. Fuel was cheap in the USA, as was the environment.

Dual-clutch automatic gearboxes are now replacing those with torque converters.
 
  • #30
@Baluncore so you're telling me in everywhere else besides the USA if one were to be driving down a flat stretch of highway at a steady speed and pushed the clutch in without changing the position of the throttle that engine would hold RPM? It wouldn't over rev?
 

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