Engine stumble/lights flicker - voltage problem?

[r1de23]

Gentlemen,

The weather is getting nice and I decided to do some work to my car prior to pulling it out for the spring. My interior lights were flickering prior to winter storage. I knew that my alternator bearing was wearing out so I decided to replace the alternator hoping to fix two birds with one stone. After I replaced the alternator... this is what happened...

http://youtu.be/WVPycU_DVfE

The interior lights still flicker (see instrument cluster lights and overhead light) and the engine appears to stumble in conjunction with the voltage drop. As you can see the voltage gauge it moving from 13 to 14v. Any ideas???

Update: Battery load tested good.

[EleCTriCT]

Year make model?

Can you put a volt meter on the battery while it is running and share your findings?

Is the battery light on?

[r1de23]

2000 996 c2

Also, I just recently inspected all major grounds from the battery/engine.

[EleCTriCT]

From your video looks like your regulated voltage is too high, that replacement alternator could be bunk!

I would verify the voltage with a meter. Or go out to a local auto shop /store that can give you a charging system check. To verify

Hope this helps

Edited February 23, 2012 by EleCTriCT

[Loren]

13 to 14 volts charging (engine running) is normal and good. It will run closer to 14 volts if the battery is low or weak.

Any aftermarket add-ons such as stereo or amps? If not I would suspect the ignition switch.

[r1de23]

My lights were dimming prior to replacing the alternator. It also dims with the engine off and on, more so with the engine idling.

[logray]

First and foremost, there is no mention of battery testing or replacement. That would be the first place I would look.

Have you looked at all of the main power leads? These are the ones that are normally suspect (corroded or poor connection).

Main positive from alternator to starter to jump point in engine bay.

Ground strap from engine to chassis.

Ground strap from battery to chassis.

There are others as well but much more difficult to access...

Main positive lead from battery to main fuse box.

LONG Positive lead from fuse box to junction above transmission.

Positive lead from junction point to jump point on engine.

[RFM]

Agree with logray about the battery as first suspect. It would appear that the battery is the culprit.