2007-06-23 01:23:38 · 5 answers · asked by Donnie Durden 1 in Cars & Transportation ➔ Car Makes ➔ BMW
Remove your battery and have it charged and tested at your local Autozone store.
Then, reinstall your battery and drive your car to the Autozone store for a free alternator test.
They perform both the above services for free.
2007-06-23 03:17:24 · answer #1 · answered by Snowie 6 · 0⤊ 0⤋
The last answer is the best answer.
You can determine if the problem is battery or alternator by removing the positive from the battery the battery is not not connected to the car so if the engine dies the alternator is not charging enough to keep the car running.
As in answer 2, a voltage check with a multi meter again you need to disconnect the positive from the battery otherwise you are getting voltage from both the alternator and battery.
The draw back with both is sometime by disconnecting the battery while the engine is running you can loose the ground reference, not a common problem especially when removing the positive and not the negative but enough of a problem for auto makers not to recommend this procedure.
Most starting problems are not voltage problems but amperage problems.And this lead to the battery. Best answer have the battery tested not just voltage but amperage, most starters eat 32 amps and 30 or 31 are not enough. You did not mention the age or your battery. Depending upon the climate that you live in 3 years might be the lifetime of a battery.
If the battery is good test the alternator.
BMW should have plenty of equipment to do this.
Best of luck.
2007-06-23 03:45:33 · answer #2 · answered by DeSaxe 6 · 0⤊ 0⤋
If you can get it started remove the postive battery cable and when you break to circut you can tell a noticeable difference or the motoer shuts off then you have an alternator problem.other wise its battery issues
2007-06-23 01:29:33 · answer #3 · answered by vanessa y 1 · 0⤊ 0⤋
DO NOT REMOVE BATTERY CABLE WHILE ENGINE IS RUNNING. it can damage the dme(engine computer). that was a valid test pre fuel injectors. the fuel inject has a 70 volt spike when it collapses and the battery is the cushion for that. if you remove the battery it is possible for the voltage to go to dme ground(seeing thats what controls the ground for the injectors.)
take your car to autozone and they can check it for you.
2007-06-23 07:35:00 · answer #4 · answered by jp 3 · 0⤊ 0⤋
While the engine is running measure the voltage, if the alternator is working the voltage should measure over 13.5 volts.
2007-06-23 01:54:22 · answer #5 · answered by Kmax 5 · 0⤊ 0⤋