SweetSally

Hi everyone, I'm new to the board. I'm having some serious problems and message boards have proven to be the best way to get help (the dealer hasn't been much help so far) This is a long post to give the history of my problem.</P>


I have a 1999 Anniversary Edition GT Convertible automatic. I love this car, but for the last year I've been having some really strange problems. It started as a loud "thump" through the speakers (yeah, volume is up a bit most of the time). It was so loud I jumped, and looked around to see if someone hit me. Then the car shut off while I was driving, with the "thump". Sometimes it wouldn't start, and I thought it was the battery cables. I'd tighten them, clean them, etc, although they looked fine. But all this happened so randomly that I couldn't tell what it was.</P>


If I left the car sitting for more than a week or 10 days, the battery would go dead. It was fine as long as I was driving it, but during the winter I actually replaced the battery once, and had to jump it5 or6 times. I thought it was because I hadn't shut the door tightly and the interior light drained the battery. The "thumping" was still happening through the radio, especially when I first started the car. If it was idling and I put the top down, "thump" again, and then I noticed the gauges just dropping to nothing, as if all the juice was gone, like someone turned the key. Then the yellow idiot light comes on. </P>


I took it to the dealer, and they said there was 'air in the gas tank' (whatever that means). They reset the computer and I took it home. Light came back on. And the "thumping" and shutting off still was happening. I took it back, they said they didn't know why the light was coming on, same read out from the computer. Reset the computer again. I'm driving home and the car shuts off while I'm sitting in traffic. Won't start for about 5 minutes, then starts right up. As I'm driving I hear the "thump" and see the gauge needles drop, then come right back up. </P>


I called the dealer (again) and brought it back. They said "alternater" and replaced it ($347) I drive it home...same thing. Start the car, turn the radio on, pull the lights on, and "thump!" the gauge needles drop and the car shuts off. Called the dealer and they said they had no idea what the problem was but we could bring it back in again.</P>


Has anyone ever heard of this? Is it the stereo?? How can I tell? I'm getting so frustrated. I can't drive the ole' girl without fear she'll shut off and leave me somewhere.</P>


any comments are much welcome</P>

99dro&#112;Top

<IMG src=smileys/smiley5.gif border="0">....that is weird as hell.

SweetSally

It's nice to know someone else thinks it's weird too. I've never encountered anything like it. The idiot light I can handle, I've had them go on for no reason, but that awful thump in the speakers and the power cutting off...scarey! It's a factory stereo btw. Everything is factory on this 99. And she has over 70,000 miles on her (I know, a lot of miles, but hey, if you gotta commute, why not do it in style?)</P>

BCisme

they probably didnt even run a diagnostic test on your electrical system, otherwise they'd have mentioned it, and charged you for it. ask them to do a complete diagnostic and see if they find a bad wire or short or something.

SweetSally

They did charge me for a complete diagnistic when the light came on the first time. The read outwas "Evaporative Emission Control system leak detected (gross leak) possible causes: Missing or loose fuel cap (not) Suspect damaged evaporative system vapor lines (not) Vacuum supply leakage/restriction (not) Suspect evaporative system vacuum or vapor hose leak (not) or EVAP canister purge valve stuck closed (not) </P>


When I took it back againbecause of the electric problemthey charged me again for a complete diagnostic and said the problem was the alternator. When I took it back a third time (when the light came on again) they put it on the diagnostic (they said) but didn't charge me cuz they couldn't find anything wrong.</P>


question: when they do a complete diagnostic ($70) is that really complete? Shouldn't the alternator problem showed up the first time? And yes, I thought this problem should have showed up, too.</P>

EvilKenevil

Man, that sucks.

BCisme

the alternator was a guess. the diagnostic tests probably didn't reveal anything new the 2nd and 3rd times. i'd take it somewhere else.

SweetSally

BC, thanks for taking the time to read my posts. I had guessed the alternater too, for the battery going dead. It used to be they just went *kaput* and you knew what it was. I had never had one limp along for a year. I remember sneaking down to the local junk yard after dark to pinch an alternator for my 58 Chevy when I was 17. </P>


Now, to find a good mechanic...dealer or private? I thought going to a certified Ford dealer would be better, but now I'm not so sure. </P>


</P>

Zcpeanut

Go private, dealer is expensive and alot of the time wont fix your problem, ask them if they have delt with a problem like yours and if they havent find one that has. Its not the alternater, that wouldnt cause your battery to go dead after a while but im not 100%, it couldve been.. normally batterys go dead when an excess of electricity is being used when the cars not moving, that makes the alternater, which provides the recharging of the battery to happen, not to turn thus not recharging the battery. the thump you are talking about is what happens to speakers when a surge of unprotected electricity happens, like say your plugging in a speaker,as yourplugging itin the electricity flows through the wires and is released in that thump (ever noticed that?), so what i think is happening is that theres either a wire problem (most likely)or a battery problem which when you turn ur lights on creates a surge that is big enough to make the car turn off and thats why u hear the "thump", the car will automatically turn off if that surge is big enough and goes to the cars computer and shuts it off... that is just a guess but i have a knowledge of audio and that ledme to believe how i came to the conclusion.... my $.02 </P>


[edit] some spelling stuff</P><edited><editID>Zcpeanut</editID><editDate>37830.6488773148</editDate></edited>

SweetSally

Excellent! Zcpeanut, I think you have come very close to describing the problem. There is a power surge (I couldn't explain it very well) and it's enough to shut everything down, sometimes fora nanosecond, sometimes enough for the motor to quit. What I can't figure out is why. There is no pattern, it doesn't happen when I hit a bump which would shake the wiring. It's very random. I need to drive without the stereo on (hard to do*wince*) and see if it still happens. That will help me to figure out if the stereo is causing the power surge. </P>


I'm not going back to those guys at the dealer. It'll be hard to find a mechanic who knows Mustangs, and even harder to get an appointment. </P>