Motor won't turn over
 

On the way to work yesterday my car died at a red light. Tried to crank it back up and it died within 4 seconds and wouldn't turn over any longer. My battery was at 11.9v, so i figured the Alt died and I just need to charge the battery and replace the Alt. Had it towed to the house and popped a spare battery in there that is fully charged and it still won't turn over.

Oil and coolant look good. If the Alt seized up would it prevent the car from turning over? When I go to start it you can hear the starter trying to turn and all the light go dim. i suspect that its drawing a lot of juice from the battery but can't spin the fly wheel.

Kinda scared that something in the motor locked up, but with the battery being dead, I keep thinking its something with the Alt as well.

Thanks,
Joe

Will have nothing at all to do with the alternator. Even at 11.9 volts the car should crank since that is well within the operating specs of a 12 volt battery.
Have you done anything to the engine? Bone stock?
I hate to say it but I am not optimistic for you with the info that you have given so far.

Well, now, @Urmyson, before you start doing major parts replacements, I would strongly suggest that you take your "spare" battery down to a shop and have it "load tested". It may show 12V but may not have the umph to turn over the engine.

Then come back ...... ;)


humfrz

The spare battery is brand new. I put a jump box on it as well and it did the same thing.

Nope, not a battery or charging issue (the total reverse of what I say about 99% of the time in these no start threads).
Starter maybe, flywheel possibly but I am going with something seized. I truly hope I am wrong on this armchair diagnosis but stand by that thought until more info is available.

So if the Alt was seized up would the belt just spin over the seized pulley and smoke?

Yes. And you wouldn't have 11.9 volts in the battery.
Have you done any mods to the car?
How is the oil and coolent levels?
When it stopped did it make any noises or any other odd action?

Oil and Coolant look good, I didn't see any metal in the oil. I'm running a ESC and OFT, so I'm not stock. When it first died it didn't make any odd sounds, but when I started it back up it ran for a few seconds and I did hear a clunk and it died again.

You can easily check to see if the engine is locked by putting the car in gear and pushing it.

Yep. Used to be able to pull the plugs and grab the fan to see if the engine would turn but that day is long gone.

OK so the fact it is FI, started and then died again and made a clunk is rather important info to have.
No oil on the ground or in the pans under the car?
The ESC didn't seize up on you? (Oh wait. No belts. Never mind that one)

Nope no oil on the road or leaking from what I can see.

OK so now try pushing the car like Billwot said. If it moves at least the engine isn't seized. If it doesn't move ...
If it does move and you have the space you could try to bump start it but there is some rick in that depending on what is wrong.

Prop valve train/rocker issue