924Board.org

flosho

Ok I've done a ton of searching, but still need help.

My alt is not charging at all, first things first, check and make sure all the wires are hooked up correctly... I have the small wire hooked to the D+ post and the red cable hooked to the B+ so thats correct.

Next I checked to see if my Alt light was coming on with the key in the ignition, nothing. Ok, after some searching I found that I can run a jumper wire between the negative battery post, and the D+ post, I do that and viola, the light comes on, so bulb is good.

Next I try to hook the D+ jumper wire to the 12v battery post, and I hold it there, and dont get anything(I didnt go all the way to loosen the cable and clamp the jumper wire connector in there.. (I will do that as soon as Im done typing this.) I check the voltage to see if the alt is charging, and all I get is 11.7ish volts at the batter, and 11.7ish volts at the B+ post on the alt.

So basically my exciter wire isn't working somewhere, but where? I trace it back and after searching the board, found it goes to the white 3 pin connector above the cam cover, and unplugged that, and looked and it didnt look to bad, so I just connected them back up. This is where I get lost and to make things worse, I have about 5 wires (besides the big power cable) running to my positive battery post, and 1 wire running to the negative battery post. Theres also looks to be a relay on the left side of my engine bay, with a spliced in 30 AMP fuse, which I will get pictures of shortly.

This is a brand new alternator as well, could it possibly be that the belt isnt tight enough? As to thats why it wont charge above 11.8 or so volts? I mean we pulled the belt tight and I tightened it down, but we didnt pull it REAL tight, but its definately not loose either.

Im stuck, the D+ seems to be bad, but dont know where to fix it at?
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flosho · Posted: Wed Oct 05, 2005 10:21 am Post subject:

Also I just noticed, when I revv the engine, the alternator sparks, it looks like the bottom mounting bracket vibrates against the bracket that holds the alt and it throws sparks everywhere.

Im wondering if I mixed something up down there when putting that bolt through, or if the bushings are worn? I did notice there looks to be a washer, thats floating around down there loose like.. Whats the order, or where does that one go? like when you bolt the alt in, you put it between the brackets and theres a washer, that seems to fit on the backside of the tab/hole on the front of the alternator, but it doesn't stay there? Any ideas?
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Paul · Posted: Wed Oct 05, 2005 10:21 am Post subject:

Just checking, you did hook up the ground wire that runs from the alternator to the intake manifold, correct?
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

flosho · Posted: Wed Oct 05, 2005 10:25 am Post subject:

Interesting, as I dont believe there was ever a wire that leads from the alt, to the intake manifold? I only noticed the 2 wires connecting to the alt...

Oh and I hooked up the jumper wire to the D+ and the Positive terminal on the battery(and actually clamped it in) and left the wire that WAS connected to the D+ post off... and after starting the battery light came on and flickered, and then I got out to check the volts, and it still only put out 11.8 volts..
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Tigger937 · Posted: Wed Oct 05, 2005 10:27 am Post subject:

Oooooooops!!!

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1981 931 (Concours)
1982 931 (Daily Driver)

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Paul · Posted: Wed Oct 05, 2005 10:33 am Post subject:

You must have the ground wire connected.....
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

flosho · Posted: Wed Oct 05, 2005 10:44 am Post subject:

See thats just it, theres no where to put a ground???

Pictures of everything

Thats the back of the alternator, theres only 2 posts, there is a little clear "L" connector, thats all covered, but it runs down to the bottom of the black plastic piece/box cover thing.

Here's that washer piece that I spoke about, its loose, and dangling.. I didnt notice where this went when I took it off, cuz it just fell to the ground right away..

The relay that I spoke off is on the bottom left there, and I have no clue what this does? But I'm more concerned about the alternator..

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Paul · Posted: Wed Oct 05, 2005 10:55 am Post subject:

It's bolted to the alternator with a 6 mm bolt (10 mm head). Looking at the back of the alternator it's at the 2 o'clock position near the edge.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Paul · Posted: Wed Oct 05, 2005 10:58 am Post subject:

In your picture the bolt is missing, but the hole at 2 o'clock is threaded for the bolt.

Reattach the D+ wire properly and ground the alternator.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

flosho · Posted: Wed Oct 05, 2005 11:01 am Post subject:

haha, omg.. I cant believe its never been grounded... I dont think my car has ever had a bolt there, the old alt didnt have the bolt you speak of, I'm going to go look for an earth strap..

Anyone have any pictures of exactly what I'm looking for?
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Paul · Posted: Wed Oct 05, 2005 11:03 am Post subject:

It's a braided copper strap, but you can use a pair of 10 guage wires if you like.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

flosho · Posted: Wed Oct 05, 2005 11:16 am Post subject:

Hmm.. this also applies to 931's? I have an 81. There has never been a braided strap from the alt, to the manifold, there is a braided strap at the back of the charge tube, but nothing that goes to the alternator?!

Do you know what size bolt would work for this? My buddy works until 9 tonite, so if I give him a call he can get one on the way home before he leaves work...

this is puzzling to me... :S

Eh, I looked at cmxxxi's picture he had, and I can see the ground strap, never had that on mine...

now on to the other question for now.. That little washer in the bottom mounting bracket, in the picture you can kinda see it floating around... where exaclty is that supposed to go??
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Paul · Posted: Wed Oct 05, 2005 11:20 am Post subject:

Reattach the D+ wire and ground the alternator with your jumper cables.

The bolt is a short 6mm (10 mm head).
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Paul · Posted: Wed Oct 05, 2005 11:25 am Post subject:

I just went out to the shop and looked at my 931, the ground attaches to a 6 mm bolt just above the voltage regulator.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

flosho · Posted: Wed Oct 05, 2005 11:32 am Post subject:

paul, i appreciate you help this evening! I will have my roommate pick up a 6mm bolt before he leaves work... It doesn't matter the thread pitch really? Just a normal 6mm.

I have some 8ga. power wire I am going to use...
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