car died in the middle of the street

Discussion in '1994 - 1995 Specific Tech' started by Road_Runna, Mar 6, 2008.

  1. Well I was driving my stang last night, for around 10 minutes, had to make a stop for a red light, I turned the radio on and everything dies. The car wouldn't start again cuz the battery is giving little to no power, not enough to start the car, or turn on my emergency lights, but just enough to make the little bulb in the hood dim just a tiny bit.

    My alternator was replaced no less than 4 months ago, car was running fine till last night.

    EDITED: The night before the car stopped, I had autozone charge the battery, tested and passed.
  2. Well should pry go to the local parts shop like autozone and have them test it. Check all wires too.
  3. Charge the battery again, and run the car and check the voltage at the battery itself with a voltmeter, it should read over 14V when the car is running (initially, anyways). If its 12V or less, check the voltage at the alternator charge cable stud (on the back of the alternator). If its also showing the same voltage, you most likely have a dead alternator again. It also wouldn't hurt to check all of the engine block grounds and make sure none of them broke-off, but its unlikely the problem. Its not that uncommon to get a bad out-of-the-box remanufactured part.
  4. Sounds like the alt to me as well. Is it just a standard one or chromed/polished? A few people have had issues with chromed/polished alts cause they don't disperse heat right
  5. The alternator's just a remanufactured one.
    1Tallmf. I've had problems in the past with other alternators, the charge stud and cable kept breaking, I think they were overheating after a good 1k miles or 2k.
  6. I say check all your connections.
  7. Brain farting here, but it might help.

    If you get it running again, check to see (carefully) if the alternator power wire is getting unusually hot. I'm thinking perhaps its getting old and crusty and may possibly have alot of resistance accross it. You can also check that with an ohm-meter if you don't want to burn yourself. I kind of want to change-out the battery cables and alternator cable on mine, they have seen better days.
  8. I found a replacement cable, for the alternator to battery cable at the junkyard for $3, you were correct about the wire getting crusty.

    Now the problem I have is my voltage meter. The dash's diagram has a range of 8-18 if im correct, well my charge is fluctuating between maybe 10 to 12 at idle, constantlly doing this whiles in idle.
    Only when I step on the gas a little is when the pin moves and stays in the middle (at 13?), let go of the gas and it starts fluctuating again.

    I replaced a ground wire, the one located right next to the oil filter to the frame, cleaned off the mating surfaces using royal purple to get rid of grease, sand paper, and finally prep contact cleaner.

    Battery is new. And the car starts everyday, but this fluctuation is driving me insane.
  9. Im surprised nobody said this yet... but jump start your car. Then while its running take the ground off of your battery. If the car dies then you need a new alternator. Besides that check all the body/engine grounds for tightness and/or corrosion. The surging sounds like the battery is dead to me because if the battery is dead then the alternator has to struggle to try and charge it while giving juice to run your car witch causes surging. I know you said both are new parts but good parts are bad right off the shelf all the time. Sometimes back to back which will lead you to believe thats not the issue.


  10. Nobody has said that because that is a great way to fry your ECU. Disconnecting the battery while the car is running provides the alternator the perfect opportunity to send and UN-buffered voltage spike through every electrical circuit in the car. With no ground wire, there's nothing to keep the voltage regulator and exciter in check.
  11. Thats funny becuase the 9 years I have been working on cars I have yet to see that or EVER hear of that happening. Makes sense I guess but highly unlikely. The 4 different shops I have worked at also say that is the best way to check if you either A) cant get to the alternator while the car is running or B) cant get a good reading. And there is a ground wire on all cars to the engine/body from the harness which in most cases ties into your ecu.
  12. do you have underdrive pulleys?
  13. This is correct. Disconnecting the negative battery terminal was the old school way of checking for a dead alternator. It's not a good practice on modern cars, because many of the modern electronics can't handle the voltage spike. If not the ECU, it can definately fry the diodes in the alternator's rectifier.

    I suspect you still have a bad ground or battery wire somewhere causing the fluctuation. Start looking for hot connections, especially when starting the car. Many autoparts stores also have a machine to do a charging test while the car is running. See if they will hook up the cables to multiple locations and test. The positive can go on the alternator stud, the fusebox positive stud, and the battery. Check the ground on the battery stud, engine, and chassis.

  14. Hey Chris i do have under drive pulleys on the car. That will be my next attempt at fixing this problem.

    Yesterday I tried cleaning what I believe is the IAC (hooked to the throttle body) with some carb cleaner, it seemed to have worked, my dash battery gauge stayed about in the middle between 8-18 (volts ?) for about 45 minutes, after the 45 min same problem started to happen again, gauge would drop and go up again.

    I'll put some video up later today, showing the problem.

    BTW, my father did the unhooking thing of the battery to see if the alternator was functional, and the engine kept going on. Also, the car will start even after a week or 2 of non-use, I don't think it's a battery problem, not sure if it's bad craftsmanship alternator yet.
  15. I guess I'm more out of the loop than I thought lol :doh: I was always told that the only thing you shouldnt do is remove the pos cable. It HAS to be the neg so it wouldnt cause a voltage spike. :shrug:

    Well at least you know for sure that both the battery and alternator work lol.
  16. OK... so to recap, it runs (for the most part) OK, but at idle the voltage is erratic, and it dies when you turned on the radio? Does it die every time when idling and you turn on the radio?

    Underdrive pulleys do spin the accessories more slowly, including the alternator, so they probably provide less power at idle. Of course, there is a high likelyhood that that does not 100% explain your symptome, but they could very well be a factor. Especially if you have stuff that draws alot of current, like a kicking stereo with a sub woofer.
  17. Sounds like the ALT.
  18. Sounds like a bad ground strap or main ground to me.

    I had a loose one near my motor mount that would move under weight transfer, (i.e. braking even a strong wind would set off my alarm in the middle of the night).
  19. Nope, car stereo system is stock, I did have it die on me once when I turned the stereo on, but that was on an old battery, and when I had the faulty alternator to battery cable installed. Since installing a new bat to alt cable and new battery I have not had a problem of it dieng on me once! still I try to avoid turning on the stereo while I have my headlights on.

    But yes, it still has an erratic idle voltage problem. Starts up really great in the morning my volt meter will stay right in the middle, after 5 minutes of driving the problem shows up. It seems to be in sync with the engines rhytm :shrug: