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It is all well within the capability of most DYIs, and pretty fun actually (call me weird). In my project I replaced EVERY harness (ABS harness soon but not yet) in the car with fresh wiring, including upgraded wire gauge for certain marginal cable runs. There is a fairly decent selection of great connectors available, Deutsche Motorsports or aero style connectors that are weather sealed. It all comes down to how much you want to spend on them. It takes time to reference the amperage limits of each connector, and based on how many wires and current it needs to hold, then pick the connector of choice. Most connectors on later 928s are pretty sturdy, and should have a fairly negligible loss. They are however pretty big and clumsy and the slim Deutsche Motorsports connectors are a great option. Same with aero-style connectors. If you are not worried about retaining the "factory" setup for originality, then go for it. If you intend to keep your car indefinitely, then at some point your +25 year old wiring WILL need attending to anyway.
It's great therapy!
Carl
Thanks Carl. I really appreciate it. I have no desire to ever get rid of the car and am doing all this for me, not for the purists. I enjoy those types of "side projects" as well. They really are therapeutic. Cost dependent I'd rather go with more modern less bulky connectors. What you've done with your project is sheer art. Absolutely beautiful.
So roughly how much does the readymade harness cost from our usual suppliers?
That seems to me like an entire critical half of this discussion that is missing.
One always needs to know what you're trading your time and effort against...
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Mark, IIRC the SeanR harness is around $750.00, and I'm told is a thing of beauty. IF I decide to go the purchase versus fabricate route, Sean's will be the one I buy.
Dr. Bob, sorry, I forgot to thank you for your valuable input. It's much appreciated my friend.
The 928Docs engine harness from SeanR is extremely nice, uses updated type materials and technology to protect the correct color wires inside the harness, and is plug an play. The wires are oriented correctly and emerge from the harness in the correct place.
If you have the old harness out on the floor, PM me with the lengths of the various conductors in my list. Also, let me know if the list is accurate; as much as I trust the wiring diagrams, there's No Substitute for actual hands-on inspection.
As far as the connectors, the only one that could be "updated" is the T18 connector, the 14-pin on the right side fenderwall. While one might be tempted to replace it with a Weatherpak or similar to make it truly waterproof, mine would stay as original. For sure I'd put new shell and pins in the upper half where the KS2 harness connects. At the other ends of each conductor, the terminals need to mate with each final element there. All except the 3-pin oil pressure sender and the boot for the oil level switch are common items.
Note that there are more than a few different variations on the wiring harness theme. Different years have differing wires and connections. Enough so that there's no single 'fitzall' assembly option.
Folks who have gone through the trouble of sourcing and investing in the various conductors, connectors and protective sleeves will tell you that doing just one yourself is not that easy. Greg's harness has a lot of careful thought put into conductors size upgrades, sleeve and thermal insulation, and some pretty excellent workmanship. I'm sure that SeanR and others are looking at the same effort and results when they build their harnesses.
And, while we are getting more familiar with the front of engine harness, the top of engine wiring for injection and sensors needs the same if not more attention. So throttle switch, idle air controller, knock sensors, temp sensors, flappy solenoid, MAF, injectors, CPS, Hall sensor, and undoubtedly more stuff, all living at the ends of some pretty crispy wiring by now.
And yes, I have modeled and built a few wiring harnesses.
Related: Several decades ago now, the local to me at the time aircraft factory was making their own wiring assemblies. The first airframe had prototype harnesses built in place, then removed to duplicate via BIG nail-boards. In actual assembly though, some of the production airframes had hydraulics and other systems in place before wiring was installed, so access and routing needed to be ever so slightly different. None of the fabricated wiring assemblies for those sections were usable. And it turned out that putting wire in before hydraulics and control cables caused random damage to any wiring already in place. And service parts might be totally different, depending on available access at the time of repair.
Maybe making a 928 front engine harness isn't so tough, considering all the possibilities. At least we know where and to what it needs to fit.
The 928Docs engine harness from SeanR is extremely nice, uses updated type materials and technology to protect the correct color wires inside the harness, and is plug an play. The wires are oriented correctly and emerge from the harness in the correct place.
No affiliation, just a satisfied customer.
Agree w John
Have one on the GTS, the 79 will have one eventually..
Hey Chris,
I built mine and like you I prefer to do most everything myself. I am going on travel Sunday and will be out of pocket for a while.
I have found a vendor (European sizes and colors exact match) that will sell the wire in the lengths needed. I though they were quite reasonable. All in all it cost me about $200.00. If I had it to do all over again..I would still build my own.
When I get back I will put together the vendors and parts I used, along with the prices. In the end, just lay it out on a board and copy.
On the larger cables I used tinned copper marine battery cables. They were cut to order and also reasonable. Tinned copper will resist the corrosion that un-tinned will not. A definite need!
I have the crimping tools and can loan when you are ready.
best,
John
Harness was a bit stiffer because of the larger diameter starter and charging cables, but still worked and fit perfectly.
I made the 14 pin wires longer to accommodate a Weather Pac connector If I decide to change it later.
I used Red heat shrink and boots to seal the Fire sleeve. The company that provided the wire also had the correct terminals.
When I originally decided to do this, Sean was putting a kit together for me but I was on a ridiculous budget and couldn't afford it (he was offering a reasonable price). In the end, I sourced my own, but he may still offer that. . Worth a try. I kinda liked doing it all myself though. There is some trial and error, so having some extra lengths and terminals was a good idea in my case.
I also needed to rebuild the injector harness. That was easier and the new injector connectors I found for a great price. That was a fun project fun! Very rewarding, and it also makes you learn your car.
At some point fairly soon I expect the market for replacement harnesses to take off as more and more of the old insulation crumbles on our cars and splicing starts to get ridiculous. The only way I could see trying to make one myself is if nobody was making what I wanted or making it in a way or with parts I didn't want.
I think it was about 5 years ago one of us decided to make harnesses, and it was gungho for awhile, then hit a wall with the choice of a Deutsch connector at the firewall.
When I was looking I think EBSracing or something like that had the wire at decent prices by the foot, and various sources for most of the connectors except to the brains and CE and those can be reused.
Thanks Dr. Bob and John. Sorry, I've been away from the keyboard.
Bob I'll try to get some measurements in the next day or 12. Busy week, and I'll be out of town for a few days.
John, and input is definitely appreciated. I'm trying to work 3 or 4 different things at the same time. I need to get all the parts/tooling assembled, then I can slow down and enjoy. :-)
I have also built harnesses for the pre - 32v engines, I didas suggested above, removed the old harness, laid it out on a board and built a jig, then made a couple for my own use.Picture is a shot before i added all the connectors ( sourced from Roger, of course).
i source the wire from Ron Francis Wiring, the same folks who supply kits for hot rods and muscle car rewires.
Thanks Dr. Bob and John. Sorry, I've been away from the keyboard.
Bob I'll try to get some measurements in the next day or 12. Busy week, and I'll be out of town for a few days.
John, and input is definitely appreciated. I'm trying to work 3 or 4 different things at the same time. I need to get all the parts/tooling assembled, then I can slow down and enjoy. :-)
Chris, thanks in advance. No hurry -- we're more than a few feet deep in snow and prediction is snow almost the whole week. An inch an hour since mid-morning.
When I originally decided to do this, Sean was putting a kit together for me but I was on a ridiculous budget and couldn't afford it (he was offering a reasonable price). In the end, I sourced my own, but he may still offer that. . Worth a try. I kinda liked doing it all myself though. There is some trial and error, so having some extra lengths and terminals was a good idea in my case.
Hi Firemn, would you mind sharing your wire source? Many thanks!
NeilH shared that link to Ron Francis Wiring in post 26 in this thread. Does that help?
I totally missed that, thanks!
Edit: dr bob, I took a look at this site, but what I was looking for was actually firemn131's reference in post #21, "I have found a vendor (European sizes and colors exact match) that will sell the wire in the lengths needed." Hopefully he will chime in.
01-06-2017, 01:31 PM
