alternator?
 

I have a new alt. (about 8 months old) in my car yet my car keeps dieing while going down the road, the reason for this is the battery is completly dead... (BTW tried with several new batteries) could it be anything else?

Have the alternator and battery tested at an auto parts store. usually for free. If they're o.k., check elsewhere. The most common problem that I've experienced is bad battery cables. They might look o.k., but they break down inside. If they're old, change them. Then clean all of the electrical connections. Corrosion builds up between them from moisture. check/clean all of your ground connections too.

I had an alternator on a car that was 10 years old. It quit charging so I went to take it off to get a new one. As I was removing the wires I noticed some corrosion and thought....hmmmm. I cleaned off the corrosion, put it back together and the alternator worked fine until I junked the car three years later.

By new alternator, do you mean a completely new one you bought from Nissan or a new to you rebuilt one from autozone or equivalent?
Check the wiring and connections like previously stated and have the battery and alternator checked like previoulsy stated as well. If those don't turn up a problem, see if the internal regulator might be the problem on the alternator. I'm not sure if any of the tests that the auto parts stores run, will check for voltage output from the alternator. If the regulator is bad, it could either under or over charge the battery causing it's failure.

yeah, turns out it was rebuilt, but it turns out it had a lifetime warranty so i got a new one free.

did that fix the problem?

well
i have no "field ground" signal coming from my alternator, basically im being told my car needs a full wiring harness because there are many "splices" into the harness itself from the owner before me, i don't know... They alternator works now but nissan says with no field ground it will only be a matter of months before the alternator kills over agian

well got a huge blessing in disguise today, all my problems should be fixed... i got a new injector harness installed, almost all the wire on the original one was corroded to almost nothing, after that we found my main harness was showing bad, or in some cases the wrong connections, although agianst nissans policy the guy was nice enough to sit there and find the problem, he had to replace sections of the main harness, everything tests perfectly now and it saved me about 1k, which is what a new harness cost installed. i'm so happy about this and can't wait to pick up my car tomorrow!

make sure you take him a case of his favorite beer as a thank you!

or 50 bucks, whichever you think he'll appreciate more. :D

heh, yeah its nice to know not every person in the world is a dick, Im going to pick up the car now, ill let everyone know how it runs!~

i think im gonna have to look into one of those in the near future. im still getting some hesitation sometimes, especially this morning. it was a little colder than usual. i get a gas smell sometimes when i am driving or sitting with the car on too.
the engine hasnt been performing like it used to before i had my problem
id like to know how yours feels,if its back up to par

Well I got the car back and I would tell you how it's running but my #5 injector doesn't work at all anymore, it was so corroded that when they pulled it off the connector and the injector plugs were corroded together, no matter how much cleaning there just isn't enough left to get a good connection (so says nissan.) For about 2 minutes of my process of "limping" my car home the injector began to work, I ran it up to a decent rpm, got ignition break down, the injector stopped working agian... So I guess the plenum is coming off (I HATE THAT PLENUM) and a new injector is going in.

you should probably try to clean it yourself before you go buy a new one
soak it with a bunch of wd-40 and let it chill for a while and try scraping at it
are you gonna replace all of the injectors or just that one? you might want to look into that so that you dont have to take the plenum off anymore

You don't need to take off the plenum to replace 1 injector. You do need to loosen as many of the plenum bolts as possible though. Once you've done that, you can usually use a prybar to move the plenum out of the way far to remove the faulty injector. I did it on mine 4 years ago. Still works fine (knock on wood). This is obviously much less time consuming.