R.King

My car just died in the middle of the road, i noticed for few mins that it was very hesitant on accelleration i felt some knocking. accompanied by the ABS light on. i limped it almost to the school parking lot where i could leave it but it died with like 100ft to go. now the car would not start at all.

all the lights in my dash are going crazy and i realized my radio wasnt working a few mins before it died, also the window took years to roll back up.

are these the symptoms for a dead alternator?

said car is a 1997 Maxima.

Finaltheorem47

get a volt meter and check your battery. If you can get it started then it should be running at around 14 (point something) volts which means its charging. If its running at 12 or less, usually around 9 if its a fully charged battery, the alternator isnt charging.


Will your radio operate when the key is turned to accessories? Then the radio shuts off the second you turn the key to operate the starter, then your battery isnt giving enough juice which would be the result of a low/dead battery or a poor connection (usually at the battery itself).

Some cars have a voltmeter in their gauge cluster and it will give you a rough estimate of the volts.

Do you have a sound system (Subwoofer) ?



Oh and after all that babbling, I'm pretty confident by reading your post that your original diagnosis is right on the money. What school do you go to?

Fabrik8

I've already fixed a Maxima of that generation with that problem. It may be the same problem you're having based on the terrible design flaw that I found. Bear with me while I try to remember what this looks like in my head.

My friend's car would shut off randomly when she pressed on the brakes, dash would turn off, radio turned off, engine stuttered, etc. Things would stop working when she hit a pothole too. So she'd roll up to a stop sign, press on the brakes, and the engine would die.

On the positive battery cable, instead of having a lug on the end and running directly into a fuse box, there is also a flat connector. This connector goes to the fuse box, and many of the accessories and electronics are on that circuit. That flat connector gets corroded, and there is enough resistance that current can't flow properly to the accessory circuits and ECU. I was tracking back voltage drops and when I got to that connection I measured a BIG voltage drop when the brakes were pressed, which was the "eureka" moment. It's a crap design by Nissan. Not all circuits on that connector are affected, and many/most aren't affected all the time.

Ok, here's the FIRST thing to check:

Measure the battery voltage (engine off) using a multimeter to make sure the battery is getting charged properly. That will obviously rule out a dead alternator that isn't charging the battery. If the battery voltage is fine, move on to the next step. If not, you likely have a different problem.

Now measure the voltage between the ground post of the battery and the other side of that connector, at some convenient point.

Then measure those two places again while someone pushes on the brakes, which should be enough of a load to make the problem show itself. If you see there is a significant different between the two readings, you've found the problem.

So, IF that is the problem:

Unplug that connection, and see if the flat connector spade looks the slightest bit corroded. If it isn't bright silver, make it bright silver. Get some fine sandpaper (600 or 800 is fine, or be gentle if it's coarser) and polish the connection up. Don't sand the crap out of the connection, you just want to get it shiny again. That's exactly what I did, and everything fired right up and worked perfectly ever since. It took me about 2 hours of head scratching and trying to isolate the problem using the schematics, and less than 3 minutes to fix it.

Here's a link to the factory service manual for your car by the way; I used it when I was troubleshooting my friend's car two or three years ago. There are likely other places to get it too, but that's one I came across and I remember it working fine.

http://www.clubmaxima.ru/?manualdownload.htm

p-stone

Andddddddd.... this is why Fabrik8 is the shit.

madsteez

How about a simple test.

Start the car,you will most likely have to use a jump box or jumper cables.

With the car running,disconnect the positive battery terminal.

If the car remains running then the alternator is fine,if the car shuts off then the alternator is bad.

SortaFlush

That theory isn't always true.

Fabrik8

It's just luck. I don't work on very many cars except my own, and I just happened to have a friend with the exact same year/make/model that had a suspiciously similar problem. Otherwise I'd have no clue except to tell him to test the normal suspects.

madsteez

That theory will easily head him in the right direction.

R.King

well it was the alternator alright, hoooked up a volt meter to a new battery with the car running, it was running at 12v exactly.