I am having issues with my car keeping voltage up...it will start off at 13ish with a jumper pack and as soon as I take the jumper pack off the car just begins to drop down until the car finally stalls out. I have a mini battery kit on the car thats about 4 months old and have never had any issues with it. I also just finished doing my clutch install and I think maybe that has something to do with it. I don't think its a grounding issue as I grounded the battery and car myself with cables and it still loses voltage. My question is the alternator the sole source of voltage dropping in an evo or is there another possible culprit to this problem. I really feel like its the alternator but its so coincidental that just after I do the clutch install I begin having issues....

 

Sounds like your alternator isn't charging. Check all the cables, etc. If not, I'd take the car in for a battery check.

 

when the car is running check the voltage directly at the alternator output...if its below 13.5v get a new alternator.

 

It could be a bad battery or your alternator.

Did you run the battery dead at any piont? Usually once a battery gets really low it never comes back.

I would try putting the original battery back in the original location and see if that fixes the issue. If you can't put it back in it's original spot bust out the multimeter and make sure you have no resistance from where you grounded the battery to where you have the original ground cable grounded. Worst case scenario take it to Autozone and let them use their load tester on it.

If the battery checks good try testing the alternator. I suggest starting with the battery because it's easier to get to.

 

since the car dies i'm assuming the alternator is at fault or a bad connection not allowing full flow of voltage.

check voltage across your teminals. turn car on. use multimeter to read voltage across the terminals (checking to see if your battery is recieving any charge from the alternator. then remove the teminals if the car dies its your alternator. if its still running, secure the engine then put your terminals back on and load test the battery if you have access to one (local auto parts store has 'em).

 

thats no good. I'll ask frank tomorrow and see what he thinks. I started taking my tranny apart today.