Bad Alternator??
 

Im starting to think that a lot of my problems might be caused from a bad alternator. Car runs fine when drive, boosts fine, pulls fine, has an idle problem and will stall at a light if my AC is running. I took it for a spin around the block came into the garage and put it in park. Car started bucking and shaking heavily, was only seeing -9" vacuum with the running lights on. Than i thought perhaps its an electrical load problem, i than turned on the headlights and the car immediately stalled. So im assuming either is a bad alternator or something wrong in the wiring harness.

Any help would be great, also when im turning into the garage at full radius car starts to buck like its going to stall.

I also noticed the radiator fans were not on but i only ran the car for a few minutes, i thought they turned on at a certain temp so maybe the engine was not hot enough.


Thanks guys

Ok, after this stalling does the engine fire right back up? Does it sound like the starter is struggling?

yes fires right back up, starter and battery were replaced not to long ago.

The symptoms you discribe sound like an alternator going bad but, when that happens, the battery drains trying to compensate for the lack of electricity being generated by the alternator. The result being that when you try and restart, the starter stuggles or when its running and you turn things on, like lights, the engine idle rmps drops as the ignition system is also running soley off of battery power. If this is not the case then I would start checking ground connections as well as all of the wires to the alternator. I recently replaced the small wires that plug into the top of the alternator via a connector because they were brittle and broken. Check these out aswell.

take the alt off and get it tested they do it free at most auto parts places.

While a bad alternator can cause the engine to do strange things (low voltage readings changes howthe ECU see's the information the sensors are providing) I wasn't aware it would change your vacuum reading.

as stated above, remove alt. and get it checked at auto zone or oreily's, IF it chekcs out good. then get a compression test. i've seen quite a many that due ot low compression, when ever heavy load I.E. A/c compressor kicks on at light. vehicle dies. but perfect any other time. just a .02 note. to keep an eye on.

*note: if you keep it reved around 1000-1100, and turn on the lights to the first click so dash come on, then second click for headlights, does the dash dim more? and does it brighten up when the revs go up???




Los

I had the same problem in 2 of my cars and it was just the wiring was bad need new wires and connections and the alternator was bad too but i would do what they said about getting the alternator checked first.

As a few others have said, get your alternator checked out first. IF it is bad, voila' you are fixed. If it isn't then you can narrow your search further.

Good luck!

*note: if you keep it reved around 1000-1100, and turn on the lights to the first click so dash come on, then second click for headlights, does the dash dim more? and does it brighten up when the revs go up???




Los[/QUOTE]

Los, the car runs better with one click, when the running lights are on car maintains a higher idle and seems to pul a little bit better. The lights do not dim or brighten when the revs go up, its a constant color.

I was hoping you could elaborate on where the wiring was bad?

thanks

I've heard of some people having problems with the wire between the battery and the alternator. While the engine is running, use your multimeter and measure voltage across that wire. Put the black lead of the meter on the (+) terminal of the battery, and put the red lead of the meter onto the large alternator wire (the nut is covered with a rubber cap). If the wire is good, the meter should display a very low voltage (less than 0.3V). If the wire is bad, it will be absorbing power, and you'll read a higher voltage. If you read more than 0.5V, you should definitely replace the wire.


You can check the ground wire in the same way: while the car is running, measure the voltage between the (-) battery terminal and the chassis of the car. You should see less than 0.5V across that wire.

-s-

k thanks guys, im going to check out some of the options you listed, I also noticed today, if I put the windows down while retracting the sunroof, the sunroof goes ALOT slower than it normally would, not sure if this is any help or not.

still having this issue...i have my car apart all over the garage so now would be the best time to fix the problem

Why would you want to move all three at the same time anyway? Anyway, that is normal. Any vehicle's windows/sunroof is going to slow up in operation when 20 million other accessories are being run at the same time.

I just rebuilt my alternator, parts cost less than 15 bucks.

putting the lights on ...makes it sound like the alt. but it would be hard to start when you turned it off, if it even started...
check the battery with a voltmeter ...go for a drive and checkthe battery again...if its low ...its your alt.

brad

now would be the best time to get the alternator tested