Argh, now it won't charge! (-72T)

Zendalar · 05-09-2002, 10:15 AM

First I had air leaks at carbs and manifolds, then accelerator pump had leaky foils...I finally got the carbs to function properly...Took a test drive....wooow...50km/h...150km/h..Speedo works, nice :9

Well, got back to garage and turned off the car and when i started..or tried...click click...The battery was dead.

Where should I start to find the problem..I tested my Motorola alternator as Hayne's manual states..Tested voltage regulator.. All seem to be ok.

I am at loss, give me clues how can I get the alternator to charge again?

D- is ground...ok B+ is constant power (to starter and battery), what is the meaning of D+/61 and DF terminals? Might DF be pre-magnetizing for the coils? Can I just put 12V from battery to DF
and try to check out if it charges?

Electro gurus

help me!

911@b-faster.com

304065 · 05-09-2002, 12:01 PM

I'm no guru (find the beard scratchy) but here's what I would do:

1. Put battery on charger for a day. Without strong battery voltage all other diagnostics are a waste of time.

2. DF= "Dynamo Field" or the alternator field (rotor). Black wire. Gotta have this energized with juice coming from the voltage regulator to charge. Make sure it's connected to the tab sticking out of the brush holder on the back of the alternator.

3. D+/61 = Pre-Excitation Current that runs through the charge warning light on your oil pressure gauge. Blue wire. Connected to the D+/61 terminal on rear of alternator. When the battery is charged and the ignition is ON and the engine is NOT RUNNING this light should be glowing. If it's not, that's a problem.

To test your charging circuit, pull off the 14-pin connector from the "console" at port rear of the engine compartment. Carefully connect MALE pin #11 (on the console) to ground using a jumper and switch the ignition on. The dash warning light should turn on.

If it doesn't, the problem is in that circuit- verify you have a good bulb and then start tracing from there.

Now, is it likely that you've got an open in the DF circuit from alt to Voltage reg? Probably NOT. How did you verify you have a good voltage regulator? Alternator?

Good luck, and please consult the wiring diagram-- it looks like a mess initially but after tracing a few circuits you can figure it out.

Zendalar · 05-09-2002, 10:23 PM

Well, voltage regulator was tested with a transformer putting out about 15.5V DC. Out came 14V. I tested all the diodes from the alternator.

Also I tested the DF connection from alternator to regulator and it showed me about 500 ohms, so i guess if it should be straight wire it should be something under 1 ohm. I am gonna re-wire that and check again.

I don't have amperage meter nor alternator warning light..thats the problem, and I don't have a clue where to hook them to. I have couple loose wires in dash but no clue what to attach to them..

304065 · 05-10-2002, 06:51 AM

OK, we've identified the problem. You don't have an alternator warning light.

The alternator warning light is the lower one on the oil pressure gauge. To the bulb holder there are two wires: a blue one, and a red one with a black stripe. The red one with black stripe is +12v from the ignition switch, that also runs across the back of some of the other gauges to power them. So that goes to one terminal of the warning light bulb holder. The blue wire goes to the other terminal. Make sure you have a correct 2-watt bulb in the socket.

Go to the Pelican main page and download the 1971 electrical diagram, part II. In the center of the diagram you will see the representation of the oil pressure gauge- it's got a "66" and "54" under it. See how the blue wire starts at the bulb, and runs all the way to the back of the car, into the console, into the voltage regulator, and then out to the engine through pin #11 of the connector. This is the circuit you have just connected. Test it by jumping the MALE pin #11 on the console to ground- the warning light should turn on. Reconnect the 14-pin connector and this should solve your problem.

But WAIT! Don't start the car until you fix the dash wires! If you have loose wires flopping around in there, you are risking a dash fire. Using the wiring diagram as your guide, reconnect everything back up. The brown wire is the ground, "daisy-chain" across the back of the gauges. The red with black is the switched +12v that also connects to the gauges. The other wires are for things like the gauge signal and warning lights, and all correspond to the colors on the wiring diagram.

Good luck!

Zendalar · 05-11-2002, 03:14 AM

It was indeed the light that was missing...and I tore it basically apart.

I searched and searched that blue wire behind the dash, but no. It was not there.

Well the thing is that PO had installed a "light" in the engine compartment. Last fall when I cleaned up the car for winter storage i decided to remove that stupid light that hangs there. I thought that it was just some..well lightening light

Last night I was wondering, what if....? I put the light on back where it was (lucky me i remembered where it was.), the other end was at the blue wire that went to "selfmade" voltage regulator and the other end...was connected to the engine room fuse box...VOILA! Voltage on DF! Started the engine and yeehaa, it was charging.

Now the car runs pretty well, although last night it was running with 5 cylinders until somebody from nearby garage came by and said, "That does not sound like a 6-cylinder".

Turns out that #6 cylinder had a bad plug. Put in Bosch plug from this motorcycle nearby, it had temperature value of 7 and my my, now it revs and pulls sooo nice

Thanks all!

911@b-faster.com

304065 · 05-13-2002, 05:21 AM

Zendalar,

Congratulations. Now you need a Porsche-approved Gnome or other small, intelligent forest creature to sit in the engine compartment to monitor the light for you, and then tap out a morse code warning that the alternator belt has broken and you are about to have a temperature-induced engine failure. For you see, the only way to tell that your alternator belt has broken immediately is to note the charge warning light when the fan stops turning!

I would recommend searching for such a Gnome at a refrigerator shop- many Gnomes were originally used to verify that the light in the refrigerator goes OUT when you close the door, but now are out of work. You should be able to get one cheap. As far as I know, there's no difference between the Porsche-made and the Karmann versions.

Or you could relocate the warning light up front.

Zendalar · 05-13-2002, 09:10 AM

Its just that now that the PO had done its things at the engine compartment, the light just illuminates, all the time (attached without the diode).

I am planning on doing this check thingie, like aeroplanes do have, although I am gonna hide it under a lid. I am gonna do it with LEDs and its going to include these lights

CDI = Green led, indicates that it has power
FUEL PUMP= Green led, indicates that it has power
ALT.LIGHT= the same as above

I was also thinking of adding this electronic stove temperature gauge (for cooking) to be added there too, it would have an alarm when a temperature reaches certain point. this would be under the lid also, at center console.

911@b-faster.com