engine not turning over

[Alkasquawlik]

my car has been acting up recently, and now when i went to go start the car, the engine isn't turning over. everything is turning on, so it's not the battery, just the car isn't getting the engine to turn over to start.

before, when it was acting up, the engine would turn over but it would turn over a little more slowly than how it usually does. once the engine was started everything was fine, but when i turned the ignition on, the car kinda "stumbled" to turn on, in a sense.

any ideas? im at a loss.

[Danny]

Starter is my first guess.

[Adrian_Visser]

I wouldn't count out the battery so quickly, just because the battery has enough juice to power the accessories doesn't mean it has enough amps to crank the engine, if you already noticed weaker starts prior to this as well that raises suspicion. Otherwise your starter may be weak.

[e30nub]

I wouldn't count out the battery so quickly, just because the battery has enough juice to power the accessories doesn't mean it has enough amps to crank the engine, if you already noticed weaker starts prior to this as well that raises suspicion. Otherwise your starter may be weak.

This, and if your battery isn't getting juice to recharge once it's started, it could be a voltage regulator/alternator.

[ak-]

I wouldn't count out the battery so quickly, just because the battery has enough juice to power the accessories doesn't mean it has enough amps to crank the engine, if you already noticed weaker starts prior to this as well that raises suspicion. Otherwise your starter may be weak.

He's right, the symptoms you described is exactly what happened to my car a good while ago. I ruled out the battery like you because it was powering everything, but apparently I was wrong. My car was turning over slowly and slower day by day until it didn't want to.
Get a recharge. If it's a no-go, new battery time!

[Adrian_Visser]

Measure the voltage accross the battery terminals. 12.5V is a fully charged battery, 11.4V is a dead battery.

If the battery isn't fully charged what is the system voltage with the engine running? should be around 14V. If not your alternator may be weak or have a bad diode and not charge your battery.

How long do you drive the car for every day? It can take an hour or more of driving to fully charge a dead battery.

That said every time you kill the battery the next time you recharge it you will only get around half the capacity you previously had.

[clean_white_eta]

Take the car to Autozone, they provide free electrical testing of the battery and the charging system.

[jlevie]

Measure the voltage accross the battery terminals. 12.5V is a fully charged battery, 11.4V is a dead battery.

If the battery isn't fully charged what is the system voltage with the engine running? should be around 14V. If not your alternator may be weak or have a bad diode and not charge your battery.

Close...

A fully charged battery will register 12.7v. At 11.9v the battery has reached 0% charge, but at 12.2v (50% charge), or below, it probably won't be able to start the engine.

With a fully charged battery system voltage should at least 13.5v at idle and rise to 14v (or a bit more) at 2500rpm. The alternator should be able to maintain system voltage very close to those numbers in the face of load from the headlights and HVAC blower. If the system voltage is lower than that loaded or unloaded, the alternator isn't working properly.

[Car Addict]

That is not exactly true if you are seeing less than above said voltages at the battery you may also have a wiring problem. I would check the output voltage of the alternator at the alternator itself not the battery.

[Surtr]

How long do you drive the car for every day? It can take an hour or more of driving to fully charge a dead battery.

Short, slow trips with the lights on, blowers going and stereo blasting can make the problem worse.

But yeah, when's the last time your replaced the battery? If you don't know, then that's probably the cause. If I were you I'd load test the battery, if it's bad replace it, if it's good, test alternator output, if that's good replace the starter.

Forgot to mention, if the battery is good, then you can start the fun job of testing for a voltage leak. Unless you are leaving something on in your car. I've had my battery drained from leaving a power inverter plugged in (with nothing in it) over night.

[Surtr]

If you're not that familiar with batteries this page has a lot of good info. http://www.batterystuff.com/tutorial_battery.html

[Adrian_Visser]

Close...

A fully charged battery will register 12.7v. At 11.9v the battery has reached 0% charge, but at 12.2v (50% charge), or below, it probably won't be able to start the engine.

With a fully charged battery system voltage should at least 13.5v at idle and rise to 14v (or a bit more) at 2500rpm. The alternator should be able to maintain system voltage very close to those numbers in the face of load from the headlights and HVAC blower. If the system voltage is lower than that loaded or unloaded, the alternator isn't working properly.

Aghh stupid memory. Thanks Jlevie.