Help, Alternator Hook up for the /6, I thought I had it right! - ZAP, ZAP.. Options

[DougC]

I have a problem where I get a major spark when attaching the battery cables to the battery. Clay Perrine pointed out to me that it's the heavy RED wire that's attached to the Starter (same place as the battery cable) and runs up to the back of the alternator. Clay suggested that this red wire was hooked to the wrong post on the altenator. OK, I removed the complete CIS injection unit and peeled back the engine shoud. The wires were hooked up to the alternator like in Wayne Dempsy's book, the pictures I took upon disassembly were lost so I had to use the book for this. I'm using a newly rebuilt Marchall alt. with external regulator. Here's a breakdown of how I have it wired:

(posts are clockwise from the top)
"+G1" or "+61" = blue wire
"B+" = Red wires [one thick, one thinner]
"another B+" = short ground strap from engine case
"DF" = black wire with spade end
"D-" = 3 small brown wires
"D." = un-used

Where have I gone wrong?

Doug C

[Porsche Rescue]

Sorry, but I am not too knowledgable on electrical stuff. Maybe someone else will chime in. I do know that the B+terminal is the hot one which carries the alternator output to the battery via the starter terminal/+ battery cable. When you connected the battery cable you were sending battery current direct to the engine case. What I don't know is if you damaged the alternator in the process (hope not).

The plastic would not affect the ground. It just needs to be metal to metal, alternator stud to engine case.

One sign of a bad alternator is the dash light remaining on when the ignition key is off and going out when key is on, exact opposite of what should happen. Haynes says this is a symptom of bad regulator but in my case it was bad diodes in the alternator.
Are the wires to the relay board correctly connected (or are you not using relay board?)? If using the board, the D+ goes toward the front of the car, DF to rear and D- (ground) off to the outside (3 prong plug). If you are wiring direct to the regulator with the connector plug, you must reverse the D+ and DF by switching their position in the connector.