Nothing, if the alternator is good the engine should keep running.On the other hand if the alternator is bad the engine will die/stall.
In a modern car with sophisticated controllers (ECM, BCM, TCM, etc.), NEVER DISCONNECT the battery with engine running. These controllers have semiconductor chips that are sensitive to voltage spikes and transients which become pronounced when battery is disconnected.. Even the power diodes in the alternator can be stressed and eventually damaged.
Power does not go to the battery, it comes from the battery, except when the car is running. At that time power does go to the battery from the alternator. Disconnect the + battery terminal.
with the car running disconnect the negative terminal from the battery if engine dies alternator is no good
I have a 1995 Ford Explorer , and with the engine running a mechanic disconnected both battery cables and it kept running - I was surprised!
Disconnect the negative terminal of the battery Leave it disconnected for an hour. (The amount of time it takes to replace the battery). Reconnect the negative terminal of the battery. This works because a transient (voltage spike, noise) is generated when the terminal is reconnected. This is not necessary when the battery is replaced because the negative terminal is normally the last connected. However, when a car's battery dies in storage for example and is recharged with disconnecting the battery, the car might not start because the computer is not running.
Disconnect the negative cable.
You don't want to do that. If your cars check engine light is on, you need to get it examined by a mechanic. Also, if you disconnect any battery terminal, your engine will not start or power any electronics while it is running.
You cross the battery.
put a voltmeter on the battery and test voltage, then start the cycle and check again. A battery at rest should be at about 13 volts, with the engine running it will be at 14 or above. to be sure disconnect the positive battery terminal while running, if there is still good volts there, or the engine does not die it is ok.
I'd check your alternator. Disconnecting the positive terminal while the engine is running will tell you. If the engine dies when you disconnect the battery, it's your alternator. If it keeps running it's something else, like your battery. I had the same problem.
i had the same exact problem with my 2001 polaris sportsman 400. It is either your voltage regulator or your stator. With your ATV running disconnect the positive terminal on your battery. IF the ATV quits instantly then its probably your stator.
Disconnect the battery.
You disconnect your battery and then reconnect your battery again.
Here is a test u can do to see if Ur alternator is good or not . when car is running disconnect the negative battery terminal it's the black wire.If car stalls then the alternator is bad if it doesn't stall then it's Ur battery is bad and u have to replace it
it should because car is running off alternator and if you do this it will not charge battery back up
There are a number of ways to test an alternator, 1,Set your voltmeter to DC most preferable set the meter to 20volts.2,with the engine running, disconnect one of the battery terminals from the battery head. 2,connect the voltmeter to the battery terminal wires and take your reading.
Start the car and while it is running, disconnect the positive cable from the battery. If the car stalls, the alternator is bad.
Never disconnect a battery while an engine is running!
No. To erase codes form an OBD-1 vehicle (made before 1996), the engine does not need to be running.On a side note, NEVER disconnect the battery while the engine is running; it will damage the computer.
Most likely cable running from stud on top of alternator to battery terminal is corroded or broken.
Remove the Negative (black) battery terminal while the vehicle is running and if the vehicle dies then it's the alternator, if it stays running then it's the battery. Although this method isn't guaranteed it's usually accurate. DO NOT REMOVE THE POSITIVE terminal (red) from the battery while it's running. It could cause a spark and make the battery explode. Another way is to drive to Autozone or Advanced Auto and ask them to test it. They'll do it for free.
If your alternator is good it should stay running until your engine dies from no fuel.
Start the truck then disconnect the battery if it's still running the alternator is good
restart the computer and by doing that disconnect the battery for 5 min
On a 1998, you can kill the running lights by pulling the the 15 daylight running light fuse in the engine comparement fuse box. Manual says to disconnect the battery before openning this comparment.
to make a quick check -- start car - disconnect the positive cable at the battery as it is running - if car stalls the alternator is bad if it stays running the battery is probably too weak to hold a charge. (daddmac)