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SharkHead
 
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Comments on a workaround invited

I did a re-wire from 14 pin down under a few years ago...all is good.

I've been doing typical maintenance and found that I have, at idle, aprox. 13.9 V at jump post but at the CP the three leads that come from the Jump post measure 13.4V. The wires are warm and harder than they should be...should have replaced during the re-wire I suppose.

Comments on this please: I am considering using the same wire type (12mm), since I have leftover, from the post to the CP in lieu of having 4mm wire at hand. I will run it into the cabin and then split it into three equal bundles to connect to the female connectors and plug into the CP.

Thoughts please!

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Old 12-11-2013, 12:49 PM
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Recovering dismantler
 
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Quote:
Originally Posted by JhwShark View Post
I did a re-wire from 14 pin down under a few years ago...all is good.

I've been doing typical maintenance and found that I have, at idle, aprox. 13.9 V at jump post but at the CP the three leads that come from the Jump post measure 13.4V. The wires are warm and harder than they should be...should have replaced during the re-wire I suppose.

Comments on this please: I am considering using the same wire type (12mm), since I have leftover, from the post to the CP in lieu of having 4mm wire at hand. I will run it into the cabin and then split it into three equal bundles to connect to the female connectors and plug into the CP.

Thoughts please!
Do you mean 12 gauge vs. 4 gauge?If so, 3 x 12 gauge wires in parallel cannot handle the same as one single 4g wire, the current capacity is defined by the cross sectional area of a bundle of wires.
4G has a surface area of approx 21 mm. 12g is only 3.3mm. So it would take approx 6 12 ga wires to carry teh same load as one 4g.
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Old 12-11-2013, 01:10 PM
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SharkHead
 
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My reference to mm is from the 928 current flow diagram. It shows the Alt wire to the jump post as 10mm and the three that go to the CP as 4 mm.

However, If I choose to use the same wire that is used from Alternator to Jump post for Jump Post to CP I would breakdown the strands into three equal bundles to connect at the CP.

Thanks,
Jon
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'79 928, 85k Opal Metallic
'99 BMW 540i, 97k Titanium
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Old 12-11-2013, 01:15 PM
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Recovering dismantler
 
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Quote:
Originally Posted by JhwShark View Post
My reference to mm is from the 928 current flow diagram. It shows the Alt wire to the jump post as 10mm and the three that go to the CP as 4 mm.

However, If I choose to use the same wire that is used from Alternator to Jump post for Jump Post to CP I would breakdown the strands into three equal bundles to connect at the CP.

Thanks,
Jon
The diagrams refer to cross sectional area, and yes - using the larger wire and splitting it should work fine.
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Old 12-11-2013, 03:13 PM
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Why not clean and redo the connectors, the wire inside hasn't changed resistance. Difference could also be your ground reference points.
Old 12-11-2013, 04:21 PM
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SharkHead
 
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I'm losing voltage down the run...wires are hardened/corroded heating dropping current. Grounds are clean.
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Old 12-11-2013, 06:40 PM
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Makes sense. Once the wires corrode internally they need to be replaced.
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Old 12-12-2013, 05:32 AM
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What you propose is almost the best way to do it. Porsche actually screwed up with the 3 separate wires from Jump Post to CE panel - it is an awful feeder implementation - it should always have been a single big wire! So yes do it.

I'm sure Porsche chose to do this (against better judgement) since its cheaper and easier to route 3 smaller wires through the boot.

However if any of the 3 wires makes a bad contact or degrades - all the current flows through the remaining wires overloading them (maybe you had this).

A single 12mm (either conducting core diameter or area mm^2) wire is good. however at the end dont split it into 3 (creates the same issue) ... make a single attachment plate that can bolt to the CE panel with a large single wire connection to it (crimped or soldered)

Alan
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Last edited by Alan in AZ; 12-12-2013 at 01:16 PM..
Old 12-12-2013, 05:47 AM
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SharkHead
 
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Alan,

I like that suggestion.

Thanks,
Jon

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'79 928, 85k Opal Metallic
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Old 12-12-2013, 09:17 AM
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