Will not start

It could be the battery, yes, but it could also be an alternator fault.

If the alternator is faulty -( usually when the rectifier pack on the back of the alternator burns out) - the battery can run to earth and become flat within seconds, or it feels like a misfire when driving.

I once had a car that needed the battery charging every time just in order to start it. Once running, there was a misfire. Then the battery was too flat to restart the car. It was an alternator fault.

Disconnect the plug/wiring from the rear of your alternator FIRST. Charge the battery. Leave the plug DISCONNECTED from the rear of the alternator. Start your vehicle.

If your vehicle starts and runs ok with the alternator wiring disconnected - the alternator is suspect. The usual culprits are the diodes in the rectifier pack (the bit on the rear of the alternator). Burnt out, they can cause a battery to become flat within - literally - seconds.

Leave the alternator disconnected and try starting the car several times. Switch on your headlamps and try and restart the vehicle a few times over a 15 minute period.

If it continually starts even when the headlamps are on, your battery probably is ok.

Even better ... take your vehicle to an auto electrician. It would probably take 2 minutes for them to dignose the problem. this saves you 'guessing' and buying replacement battery/parts that aren't at fault.

It doesn't sound as though you have a big problem .. just one of the many 'irritations' that we motorists suffer...

If the problem is the alternator there's no need to replace the whole unit - you can replace the rectifier pack on the rear. If it is the battery at fault (an auto electrician will tell you within seconds) .. well, that's life.

Its seems voltage regulator issue.Get the vehicles charging system inspected.

To troubleshoot these issue i suggest you few helpful links with solutions:---Click the link below:----

How to inspect Vehicles Alternator?

http://repairhelpcenter.blogspot.com/2011/11/how-to-inspect-vehicles-alternator.html

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How to Test Vehicles Alternator?

http://repairhelpcenter.blogspot.com/2011/11/how-to-test-vehicles-alternator.html

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How to Service Vehicles Alternator?

http://repairhelpcenter.blogspot.com/2011/11/how-to-service-vehicles-alternator.html

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How to Replace Alternator?

http://repairhelpcenter.blogspot.com/2011/11/how-to-replace-alternator.html

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How to monitor Vehicles charging system?

http://repairhelpcenter.blogspot.com/2011/11/how-to-monitor-vehicles-charging-system.html

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Car Alternator making noise?

http://repairhelpcenter.blogspot.com/2011/11/car-alternator-making-noise.html

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Car Alternator Working Intermittently?

http://repairhelpcenter.blogspot.com/2011/12/car-alternator-working-intermittently.html

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Car not starting or turning over indicates towards multiple possibilities. It can be issue with battery or weak battery. But if battery checks out ok, then it can be starter issue or faulty alternator or problem with low fuel pressure or no spark at spark plugs due to dirty spark plugs or faulty ignition coil or injectors getting cracked or dirty and needs to be cleaned.

To confirm the problem, the basic troubleshooting is required.

From start to end troubleshooting these problems I suggest you to check the help link below and follow its procedure: -----

Mostly all types of car no start problems are discussed here with solutions:---

CAR NO START: ENGINE NOT TURNING OVER:

http://alltypesofpartsreplacing.blogspot.com/2012/11/car-no-start-engine-not-turning-over.html

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These will help.

Thanks.

Thanks for choosing FixYa and welcome. You need to make sure the battery is holding a proper charge. Clean the terminals and clean the post. You could have a weak alternator draining your battery. You can test it by starting the car and unplugging the hot side battery terminal once the battery is charged. If it dies instantly, your alternator is bad. You may need a new battery.

Hello,
When you say battery voltage how are you testing it? Are you looking at a gauge on the dash? Or are you physically testing it with a multi meter? If the truck is dying and you recently replaced the alternator and battery I would first suggest you to check all them connections again real good. Snug them all up. Check for corrosion and clean as needed. Did you replace the battery and alternator with new/re-manufactured battery and alternator? The alternator needs to put out at least 13.6 volts to charge your 12 volt battery or the battery will not maintain a charge. However the alternator runs the vehicle once it is started. The battery is used only to start the car and then the alternator runs it. So if your vehicle starts and runs and then dies you may have a bad alternator. Check your connections first and then test the alternator with a multi meter. Anything less than 13.6 volt will not suffice. 14+ volts would be the hopeful output of a good alternator.
regards, Tony

you my friend have a dead battery. Replace battery and problem goes away

Replace battery .Start car warm to normal, check alternator by removing battery negitave cable, if the engine quits running replace alternator if it keeps running the alternator is fine. As far as the serpentine belt goes it will not prevent the car from starting.However if the belt looks like it needs to be replaced then it might be a good idea to do so.Good Luck.

The battery light is usually an indication that the battery is not charging. This could mean your alternator is bad but sure to check the alternator belt tension carefully. If it is loose, it can make the alternator appear bad.

you have a voltage drop.fine the damaged wire going fro mthe positive terminal of your battery to your alternator.fix this or it will keep working the alternator and draining your battery.

Nope, but they are usually near the battery, solenoid or starter (where main service wires are)

It sounds like you replaced the alternator because it was not charging the battery.
(Although no alternator can charge a shorted battery).

So now after replacing the alternator, the battery is still dead and can't be expected to charge until the engine runs for awhile. Well....the car starts and cranks from only the battery, not the alternator.

You could jump start the car with jumper cables from another vehicle to give the alternator a chance to do its job.

I suggest charging the battery from a stand-alone battery charger (about $50 any auto parts store, etc ).

You have not said anything yet that verifies that you have tested the battery.
If your battery is more than 2 or 3 years old, you may want to replace it.
They typically don't last much longer than that.

(By the way, I've never heard of a "crank sensor")