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]

You definitely need a ground from the tranny to the body. Get a strap or cable with a hole on each end, about a foot long. There is a small stud welded to the trunk floor near the rear of the tranny. Use some sandpaper to make sure the surface at the base of the stud is clean and "raw". Attach the cable to the body stud and to one of the studs with the 13mm nut at the rear of the tranny case. The stud will need a 13mm nut (wrench size) and washer as well. An alternative is to run a cable from one of the studs mounting the starter to the body. I have one from the starter mount stud to my bulkhead engine mount.

I am confused about an alternator light vs. generator light. I don't think you should have two. I have only one (using a 911 combo gauge). The electrical one is red with a "G" symbol below and is the warning light for the charging circuit, comes on with the key and goes off if engine is running and alternator is charging. The other lights I have are oil pressure (green) and brake warning/e-brake, also red, at the top.