need help diagnosing electrical problem

[1996TalonEsi]

I had a new engine put in my car about a month ago, and ever since I've had electrical issues. My alternator is new, battery is new, and after I drive my car for about 100 miles or so, the dash lights start flickering, and my battery light comes on. Today, it came on again after my mechanic "fixed it" and i took it home to check the voltages. It read at 14.5 when running, and 12 when it was off, so I'm sure my alternator is good. Also, I checked the alternator fuse and it looked good. Any suggestions on what else to look for? Thanks for any help.

 

[luv2rallye]

First make sure your grounds and battery cable terminals are clean (no corrosion) and tight.

Sometimes new batteries aren't good (just like many new alts aren't good). First make sure battery is charged up. Then with engine off measure battery voltage. Then turn on headlights to high beam and radio and blower. If battery voltage drops more than 0.5V your "new" battery is no good.

If battery and alt is ok check for possible shorts which may be draining battery: http://www.dsmtuners.com/forums/showthread.php?p=1496998#post1496998

 

[toybreaker]

Please check the electrolyte level in your battery. A low battery level can also create some funky issues after the car's been driven for a while. It's amazing how many times it can create drivability/charging problems.

If your battery resting voltage was a flat 12v, (after driving the car a bit), and the alternators making 14.5 volts running, I think it's going to be battery time real soon.

The battery should be at least ~12.5ish resting...

 

[PimpDrive]

yeah i would say its a poor ground.