Question: Does bad alternator cause to shut the engine off?

[frappiculo]

Hello everyone,

I am having a problem with my car. The car has been sitting 5 months (in a collision center due to traffic accident) and after picking up the car from the mechanic, while driving it the engine shuts off completely and the transmission goes to N and the car's engine won't operate. It happened around 15-20 times already. When this problem started happening, I had to pull over the car and start the engine again, then no issues but for instance preparing to stop at the red light the car stalls and engine goes off. It was a frustrating problem for me and I have gone mad.

Following day right after the problem that I've had I took it to my mechanic. He told me before that the alternator was bad and I have to replace it soon. Anyways he checked it and did a test drive around 10-15 minutes long and he said nothing happened while he was driving the car, however he mentioned that the car throws an error code due to misfire but he could not figure out what it was. So I was told to change the alternator.

Do you guys think that bad alternator causes the engine shut off completely? While driving the car sometimes it starts jerking and then when I press the gas pedal all the way, the problem goes away and I keep driving it without problem.

Thank you in advance for any comment and idea.

[mugglechild]

100% will cause the engine to shut off. The alternator is what provides the voltage to all the onboard electronic controllers. Once that flow stops, eventually those components become unstable and shut down and the engine will shut down shortly after. Not uncommon to see all sorts of warning lights (ABS DSC SRS etc) come on as well as those respective modules start to lose power.

[SVH]

Any warning lights? My alternator died, was putting out less and less juice and the warning lights started cascading untill the car wouldn't start. Restarting the car reset everything untill the voltage was getting too low to start again. Also had to replace the battery.

[Dave07997S]

Its the alternator that keeps the car running, not the battery. The battery is there to crank the starter and act as a capacitor. If the alternator dies or doesn't function properly the car will run off the battery and eventually it will die.

Dave

[Gossypiboma]

"Question: Does bad alternator cause to shut the engine off?"

[Redd]

Yes a bad alt will cause the car to shut down.

BUT...

If it were a bad alt, you should not be able to restart the car again. So, your issue does sound to be electrical but not a bad alt.

The car gets its electrical supply from the batt, which is in turn kept charged by the alt. If your alt were dead, you could still drive your car for as long as there is juice in the batt. Once the batt runs flat, you will get the Christmas lights of errors. Then your gearbox malfunctions, followed by your car stalling. You will not be able to restart the car after that. I experienced this first hand in the M3, and in many other cars. The M3 alt does fail without warning, but I did get intermittent low battery voltage errors about a month before the alt failed completely.

So, your issue does not sound like a dead alt. To me it sounds more like a loose connection somewhere, or a failing batt. Check your grounding cables, main charging cables from alt to batt, batt to starter. Check coils, etc. Good luck.

[bknight2851]

Sorry to restart this thread.

Did you ever find out the problem?
Currently having what sounds like the same exact issues and can’t find the source