New problem!!!!!!

[punisher72]

Ok im having probs with my battery going flat ova a couple of weeks even if i drive a few times a week? When connecting the battery terminal there is no spark which indicates there is no power draining. While the car is running i take the earth terminal off the battery and car dies straight away? Is this normal with msd and electronic ignition? To me that indicates that my alternator isnt charging? Is this right?  Can someone please shed some light?

[mopardave]

sounds like the alternator is dead, how bad of a draw does the car have not running with everything hooked up?

[426HEMI]

sounds like the alternator is dead, how bad of a draw does the car have not running with everything hooked up?

   sounds like the alt is not charging like it should.  I would check that first may not be putting out enough to keep the battery up

[punisher72]

Mopardave,Im not sure what u mean? 426HEMI, whats the best way to check if alternator is charging? When running it reads 12.9 volts then when revving its 13.3 from memory! When not running its 12.9 at different points!

[mopardave]

if your alt is fielding under load then you need to check a dead draw when the car is not running, disconnect the positive cable and put a test light in between
the cable terminal and battery post, in theory it should not light if no draw, if it does light up read it with a meter to get an idea of voltage being used. start unplugging parts until it doesnt light. something can be shorted and you may not know it.

[6packCuda]

Sounds to me like your alternator is charging but not enough. You should have closer to 14.5 Volts when running.

[Aussie Challenger]

 

Mopardave,Im not sure what u mean?  whats the best way to check if alternator is charging? When running it reads 12.9 volts then when revving its 13.3 from memory! When not running its 12.9 at different points!

  Check the voltage at the battery when the headlights (high & low beams) are turned on. The 13.3v is very low, I suspect a field has gone in the alternator. Idling should be high 13's, above idle it should go up around 14.5v and when headlights are turned on should not drop below 14v.

[FY1 RT SE]

Ok im having probs with my battery going flat ova a couple of weeks even if i drive a few times a week? When connecting the battery terminal there is no spark which indicates there is no power draining. While the car is running i take the earth terminal off the battery and car dies straight away? Is this normal with msd and electronic ignition? To me that indicates that my alternator isnt charging? Is this right?  Can someone please shed some light?

Best way to kill an alternator is to remove the cable from the battery when the car is running.

[Super Blue 72]

My  is that  I would pull out the alternator and bring it to NAPA or Autozone to have it tested.

Also, are you running any aftermarket stereo/amps or anything like that?  Alarm system?

If it isn't a bad alternator situation, I agree with mopardave to use a meter between the battery post and the cable terminal with the cable off the battery when the engine is off to see what sort of an amperage draw you are gettin.  I don't know off hand what the acceptable limit is.  If there is a draw killing you battery and it's not a bad altrnator, you can disconnect the different parts like mopardave said to see when the amperage draw decreases or unplug fuses to the various components.

[72cudamaan]

Electronic ign. systems require more voltage to operate. You definitely have too little voltage going to the battery.  But you really need to check amperage input as well.  You might have a bad cell in the battery so that it wont accept a charge. Either way 13.3 volts is not enough to run the car and put much if any charge back into the battery.

[punisher72]

You guys are awsome  I took the + terminal off while not running and there is no draw whatsoever! The battery is brand new and is a big 660 cca truck 1. The alternator is all shiny and looks new,but who knows what condition its in? Next step is to check the voltages with lights on etc. I will get back shortly 

[punisher72]

OKKKK. The alternator isnt charging which is strange as it was a couple of weeks ago? Its christmas eve and theres no leckys open  Maybe a good mate of mine might be able to help me out  To top it off it was raining and when i turned my wipers on the middle of the blade holder hits my TA bonnet  Let this year be ova a bit quicker please!!!!!!

[Strawdawg]

Best way to kill an alternator is to remove the cable from the battery when the car is running.

Definitely not the right thing to do

[dodj]

While the car is running i take the earth terminal off the battery and car dies straight away? Is this normal with msd and electronic ignition?

If your car was missing the engine to body ground strap...yes.

When running it reads 12.9 volts then when revving its 13.3 from memory! When not running its 12.9 at different points!

A 12vdc battery is really a 13.2vdc battery. So you need more than 13.2 volts to charge it - 13.3v isn't enough. Revving should be over 14.5 volts.  12.9 with it not running, to me, would mean a good battery. 
While it may be your alternator, the voltage regulator is still in the running. 

[73EStroker]

Never undo the battery and simply let the car run on the alternator. What happens is you can screw up the regulating circuit so the field in the alternator keeps weakening which causes the alternator to go into both overcurrent and overvoltage situations. You can get up to about 125VDC this way and goodbye lots of electrical thingys in your car. If you have to check the alternator place a voltmeter across the terminals  - check the readings with 1) engine off 2) engine idling and 3) engine at about 3000RPM. You should see the voltage go up to about 14.5 volts max. Little higher is ok but not too much though.