Master Mechanic offering free repair advice;

Do this:

Start the car and leave it running, then disconnect the negative battery cable:

Does the car still run, or does it die?

Let me know.

thanks

Alpha.

 

Did you check your coil packs?

 

Started the car and took off the terminal, car was still running. sounded slightly different and all the gauges went flat in my instrument cluster. Reconnected the terminal and everything went back to normal. Batt was at 12.6 before i started the car, then went to 13.6 with it running, and then after i disconnected and reconnected the negative terminal the batt read 14.2 volts.

 

Understand-

An alternator can produce voltage, yet no amperage, this can and will keep the battery/charge light off, but, it still wont charge the battery because it has no amperage- this is usually due to two things, one; a shorted battery that killed the alternator, or, two; a rectifier that sent ac voltage to the battery and killed the battery.

remember- the battery is out of the picture once the car is started- unless it is shorted to ground. All the battery does is start the car- that is it.

 

I've replaced my coil packs multiple times, and none of the dead coilpack symptoms seem to make me think that they're related, unless there's something i'm missing

 

Ok so we know the alternator is working correctly- this is good.

Can you tell me a more precise description of what is happening- does it die while driving or is it other? please include anomalies, such a temps and weather. Do you have any warning before this happens?

 

Not trying to hijack the thread... When I have had issues like this it has either been coil pack related also grounding kit related and or MAF related. Have you scanned the car? Did you throw any codes? Do you boost ok? Any other symptoms?

 

So why do my instrument cluster and windows go dead when the batt is disconnected with the car still running? disconnecting the battery seemed to replicate the problems that i've been having while driving, or it at least created the same symptoms. but if i understand it disconnecting the batt is just a way to test the alternator yes? no?

 

coil packs will cause misfires and there by a check engine lamp.

there is a fan control module that can short out, it is located near the LH side of the radiator fan, see if it has become "green treated" with weather conditions.

yes - disconnectiong the battery allows the engine to rely on the alternator and it's wiring- if this is bad the car will die.

 

don't have my friend with vag-com to scan it for me, but no lights have shown up recently, and i have a relatively new MAF. Boost definately seems to be down, but i also haven't been putting in premium gas and i have the apr high octane chip.

I'm going to check the fan control module now, hawaii's weather and being near the ocean so often definately tends to affect these things.

So this is what happens. While driving i'll notice that the entire gauge cluster goes dead, all needles rest at 0 and any lights turn off, except for the Battery light which turns on. During this time i can't roll up or down my windows, but blinkers do work, and the car seems to drive fine. Then everything will turn back on, gauges work correctly, and the batt light turns off. It will flicker, or stay on/off for minutes at a time. And then when i try to start the car later the batt is dead.