Possible Alternator Issues, Low Voltage Readings Options

[mzapisek]

Installed the new LED lights on the car over the w/end. Noticed some flickering which led me to start checking voltage readings. I have 3.0 GT clone that I have been sorting through the past couple of years. Car came equipped with the Valeo A14N11 alternator. Currently battery is showing 12.5V at the posts when car is at rest. While running the battery shows 12.3V at the posts. I'm only getting just over 10V at the headlight plug. Obviously this drop in voltage is causing the LED's to flicker.

Bigger question is why I'm not seeing 13.5V when car is running. I've been running the car for the past few months a couple days a week and have had no starting problems so the battery must be getting some charge from the alternator. Is there anything else that might cause the lower voltage readings at the battery while running as well as the voltage drop at the headlights? Really don't feel like dropping the engine to swap an alternator if its not necessary.

Additionally I have been trying to solve a stumble in first gear. The car has weber 40IDA3C's. Could the lower voltage condition also be causing a problem with spark at lower RPM's? The car runs strong above 2500rpm but stumbles coming off idle.

Sorry for rambling. Having fun working on the car but could use some advice.

Thanks.

[GeorgeRud]

I'd try swapping out the voltage regulator first as that's cheap and easy to get to. Check your battery connections and grounds as well.

Removing and replacing the alternator on a -6 is a pain in the behind, but it can be done (just barely).

[mzapisek]

I thought the Valeo had an internal voltage regulator? I will check my panel when I get home to see if and external regulator is mounted. Would love for it to be the case. Thanks.

[914Sixer]

Valeo has internal voltage regulator.

[mzapisek]

Thanks. That's what I thought.

[porschetub]

I thought the Valeo had an internal voltage regulator? I will check my panel when I get home to see if and external regulator is mounted. Would love for it to be the case. Thanks.

Yes that type should be internally regulated,is you charge light on? ,if not check to see the lamp hasn't blown that will stop the altenator 'exciting' hence no charging.
You need to investigate all option cause removing it isn't easy as mentioned.

[jcd914]

I don't recall the years/engines it applied to but there was a bulletin from Porsche indicating some Alternators required a resistor be added to the charge indicator light circuit. Effectively this increases the current flow thru the Alternator field when the key is on but engine is off, how the alternators magnetic field is energized initially.

Jim

[mzapisek]

Green generator light comes on and goes off in two seconds when the car is started. As I have stated the car has been run since June with no starting problems and battery still reads 12.4V when the car is off. Is there any specific way to test the alternator and confirm its not charging correctly without removing? Would hate to go through the trouble of removing to find out its a good unit. Thanks.

[porschetub]

Green generator light comes on and goes off in two seconds when the car is started. As I have stated the car has been run since June with no starting problems and battery still reads 12.4V when the car is off. Is there any specific way to test the alternator and confirm its not charging correctly without removing? Would hate to go through the trouble of removing to find out its a good unit. Thanks.

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Your altenator belt is correctly tentioned right?,start the engine and do a full load test headlights ,stereo,fan blower,etc,if you don't have 13.8 volts you have no charging.
There is a chance you have a bad battery but I expect you have checked that,good luck

[oakdalecurtis]

Be sure to lift your relay board out and look at the bottom. The relay boards were sealed underneath with a tar like substance that degrades and melts away in time from the heat, especially under the hot VR. If that happens, the contacts under the board for things like the VR just push down instead of making good contact. Here's a picture of what mine looked like before I replaced it and solved my electrical problems similar to yours. (IMG:style_emoticons/default/piratenanner.gif)