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Porscheaddiction · Posted: Fri Mar 24, 2006 1:01 am Post subject: Starter/battery wiring question?

While the head is out of my car I decided to change something else the heavy wire going from battery to starter (positive lead). I found something odd while removing the lead from the starter assembly pole, To get that wire off another wire was in front of it and that wire was brown! a GRND wire (all GRNDs used in these cars are brown/or copper stranded, correct me if I'm wrong). Basics of both electricity and electronics show that this is a dead short. The car started and ran fine like this for years before the head went. Am I missing something here? to me this brown wire should not be going to any pole that a positive lead is going to also. Does anyone else have two leads running from the same positive pole on the starter assembly one going to batt and the other a brown wire?
Thanks
Chris.
_________________
1981 924 NA (Restoring mode)
1984 928S (Enjoying the driving season)

seanski44 · Joined: 13 Mar 2006 Posts: 532 Location: Nottingham UK

i can't answer your question directly, but I can say this. I had a short on that part of the wiring loom, and had to order a replacement from Germany (approx £50) - The loom part starts at the plastic connector at the back of the engine bay (to the right when viewed from the front) and includes wiring for the starter motor and alternator. Apparently when mine was replaced it was pretty much bare wires around the alternator area... the car ran intermittently with this fault, but would drain the battery if I didn't disconnect it. - I had someone else replace it and the time taken was 4 hours, part of the job involved moving the exhaust downpipe out of the way... good luck!
_________________
1998 BMW Z3 2.8 arctic silver & red

1981 168HP 931 S2 blue/tan leather - SOLD

1985 121HP 924 2.0l na modded - SOLD!
1992 968 lux SOLD
1989 944 2.7 lux SOLD

Porscheaddiction · Posted: Fri Mar 24, 2006 1:52 am Post subject:

my wiring harness seems ok its just I find it very odd to find a ground wire hooked to where the positive lead of the battery goes to.
Chris
_________________
1981 924 NA (Restoring mode)
1984 928S (Enjoying the driving season)

seanski44 · Joined: 13 Mar 2006 Posts: 532 Location: Nottingham UK

Porscheaddiction · Posted: Fri Mar 24, 2006 2:32 am Post subject:

The loom may do several jobs but basic electronic theory is that you dont have a negative grnd going to a positive feed.
Im not sure why there is a brown wire on the the starters positive pole it doesnt make sense and makes me wonder how the car was able to start all this time.
Maybe there is something I dont understand about it but I would sure like to know for sure if that brown wire should be hooked along with the positive lead directly from the battery like I found it originaly.
Chris.
_________________
1981 924 NA (Restoring mode)
1984 928S (Enjoying the driving season)

seanski44 · Joined: 13 Mar 2006 Posts: 532 Location: Nottingham UK

Porscheaddiction · Posted: Fri Mar 24, 2006 3:58 am Post subject:

It has never shorted out the car has always started with no problem its just I find it strange to find this wire on the positive post of the starter together with the positive power lead from the batt.
Chris
_________________
1981 924 NA (Restoring mode)
1984 928S (Enjoying the driving season)

Ozzie · Posted: Fri Mar 24, 2006 6:42 am Post subject:

Is it original?
If someone else installed the wire it could be a pos feed to something else.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

Porscheaddiction · Posted: Fri Mar 24, 2006 3:35 pm Post subject:

Yes it appears to be original its coming off of the original harness.
Chris.
_________________
1981 924 NA (Restoring mode)
1984 928S (Enjoying the driving season)

Ozzie · Posted: Fri Mar 24, 2006 4:20 pm Post subject:

Probably meant to be a red going to the alternator.
Other colors should be red/black and black.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

Porscheaddiction · Posted: Fri Mar 24, 2006 4:47 pm Post subject:

that is exactly whats there black/red and the heavy black wire that would come from the positive terminal on the battery. The brown wire I am talking about is on the same post on the starter as the heavy black wire. This is what is confusing me
Chris.
_________________
1981 924 NA (Restoring mode)
1984 928S (Enjoying the driving season)

Mike924 · Joined: 12 Aug 2004 Posts: 2601 Location: IoW UK

There are two things you can do, Chris.

Since you seem to have a appreciation of electrical theory, you can get a meter and measure the resistance between the brown wire and a good ground point (say the engine block). If there is a very low resistence (less than 1 ohm), that would indicate a direct connection to ground which would not really be a good thing.

The other, much simpler thing to do is simply to disconnect the wire and see what happens. If something suddenly stop working it was poabably connected via that wire.

Just a thought, how is the resistance wire to the coil connected on your car? Is it in the wiring or does it have separate resistors?
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1985 Porsche 924 'Lux', Kalahari Beige (my ex)
1993 Porsche 968 Coupe, Midnight Blue, 6 spd

'There is no substitute for a little grease under your fingernails.' - Chrenan, 924board.org

Ozzie · Posted: Fri Mar 24, 2006 6:32 pm Post subject:

I bet it is the +ve for the alternator.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

Porscheaddiction · Posted: Sat Mar 25, 2006 1:13 am Post subject:

I think Ozzie is right I went out this morning and started following the wires and it running from the positive terminal of the starter to the alternator. I just find it odd that its brown.
Thanks everyone
Chris.
_________________
1981 924 NA (Restoring mode)
1984 928S (Enjoying the driving season)

N-Dub · Posted: Sat Mar 25, 2006 1:35 am Post subject:

I am having problems starting. I will most likely take my starter out and have it rebuilt today. When I turn the key, it makes a click, and some of my gauges go all the way to the right. But then every once in a while, the car will crank. Is it my starter that is gone, or do I have a short?
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'79 924 now Totaled! Carrera GT bodywork for sale!
'87 951