What wire to buy? Recreating engine harness
#1
What wire to buy? Recreating engine harness
Well I got 12 Bosch injector plugs and have basically charted out the wiring diagram. I just need to get the proper wire. I know it's hot as hell in the Vee, I'm hoping to get the wires up next to the fuel rail. If not though, what should the wire temp handling be at? I found some 16awg that's rated about 250 Fahrenheit. Is that a decent wire temp? I'm going to wrap it in the plastic shield tubing also. And voltage wise?
Last edited by 944xjs; 06-10-2017 at 04:39 PM.
#2
Join Date: Mar 2008
Location: Pacific Northwest USA
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I use "TXL" grade wiring from Painless Wiring. Seems OK to me; no problems; I'm not an authority on wire specifications.
IMO the most important thing, over and above wire specification, is to get the wire bundles elevated out of the Vee so there isn't direct contact with the engine.
18 Gauge Light Blue TXL Wire w/Black Stripe (25')Details | Painless Performance
Cheers
DD
IMO the most important thing, over and above wire specification, is to get the wire bundles elevated out of the Vee so there isn't direct contact with the engine.
18 Gauge Light Blue TXL Wire w/Black Stripe (25')Details | Painless Performance
Cheers
DD
#3
I use "TXL" grade wiring from Painless Wiring. Seems OK to me; no problems; I'm not an authority on wire specifications.
IMO the most important thing, over and above wire specification, is to get the wire bundles elevated out of the Vee so there isn't direct contact with the engine.
18 Gauge Light Blue TXL Wire w/Black Stripe (25')Details Painless Performance
Cheers
DD
IMO the most important thing, over and above wire specification, is to get the wire bundles elevated out of the Vee so there isn't direct contact with the engine.
18 Gauge Light Blue TXL Wire w/Black Stripe (25')Details Painless Performance
Cheers
DD
#4
TXL is what most of the manufacturer's use. And is designed for engine bays. GXL is the next step up.
You could use PVC and keep it high as Doug suggested it should last another 20-30 years.
Voltage rating in wire is only the break down voltage of the insulation and most will rated at least 500volts, current rating is more important, and the longer the wire run the heavier duty the wire needs to be. 16ga IIRC is rated at around 20amps and should be fine for the injectors.
You could use PVC and keep it high as Doug suggested it should last another 20-30 years.
Voltage rating in wire is only the break down voltage of the insulation and most will rated at least 500volts, current rating is more important, and the longer the wire run the heavier duty the wire needs to be. 16ga IIRC is rated at around 20amps and should be fine for the injectors.
#5
TXL is what most of the manufacturer's use. And is designed for engine bays. GXL is the next step up.
You could use PVC and keep it high as Doug suggested it should last another 20-30 years.
Voltage rating in wire is only the break down voltage of the insulation and most will rated at least 500volts, current rating is more important, and the longer the wire run the heavier duty the wire needs to be. 16ga IIRC is rated at around 20amps and should be fine for the injectors.
You could use PVC and keep it high as Doug suggested it should last another 20-30 years.
Voltage rating in wire is only the break down voltage of the insulation and most will rated at least 500volts, current rating is more important, and the longer the wire run the heavier duty the wire needs to be. 16ga IIRC is rated at around 20amps and should be fine for the injectors.
#6
Well that is interesting.
I did both mine pre computer days etc.
I simply purchased a roll of 3mm Trailer wiring, Wurth brand, of the 7 core spec. That gave me 7 colours, goodo.
I also decided that the EFI loom was going to sit under the inlet manifolds, on top of the camcovers.
Being as I am different (some say special) I also rewired the engine bay, waaaaaay too many crispy wires to just do a patch job. That led to removing many electrickery items out of the engine bay, and the wiring done in such a fashion that the loom traversed the rear of the engine bay (up under the scuttle panel), and the required "mini" looms traveled from the rear to the front as needed, thus eliminating the under a/c fiasco, and lots of looped wiring down the RH inner guard.
The EFI loom was finished with a header wrap covering (local speed shop supplied), and that has kept that loom soft and pliable since 1994.
This snap shows the basics of the engine bay, and some of the wiring is visible. I took no snaps back then, no thought of the future.
I never gave heat range etc any thought, just knew it needed doing, and simply did it.
I did both mine pre computer days etc.
I simply purchased a roll of 3mm Trailer wiring, Wurth brand, of the 7 core spec. That gave me 7 colours, goodo.
I also decided that the EFI loom was going to sit under the inlet manifolds, on top of the camcovers.
Being as I am different (some say special) I also rewired the engine bay, waaaaaay too many crispy wires to just do a patch job. That led to removing many electrickery items out of the engine bay, and the wiring done in such a fashion that the loom traversed the rear of the engine bay (up under the scuttle panel), and the required "mini" looms traveled from the rear to the front as needed, thus eliminating the under a/c fiasco, and lots of looped wiring down the RH inner guard.
The EFI loom was finished with a header wrap covering (local speed shop supplied), and that has kept that loom soft and pliable since 1994.
This snap shows the basics of the engine bay, and some of the wiring is visible. I took no snaps back then, no thought of the future.
I never gave heat range etc any thought, just knew it needed doing, and simply did it.
Last edited by Grant Francis; 06-11-2017 at 03:26 AM.
The following 2 users liked this post by Grant Francis:
Doug (06-11-2017),
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#7
Well that is interesting.
I did both mine pre computer days etc.
I simply purchased a roll of 3mm Trailer wiring, Wurth brand, of the 7 core spec. That gave me 7 colours, goodo.
I also decided that the EFI loom was going to sit under the inlet manifolds, on top of the camcovers.
Being as I am different (some say special) I also rewired the engine bay, waaaaaay too many crispy wires to just do a patch job. That led to removing many electrickery items out of the engine bay, and the wiring done in such a fashion that the loom traversed the rear of the engine bay (up under the scuttle panel), and the required "mini" looms traveled from the rear to the front as needed, thus eliminating the under a/c fiasco, and lots of looped wiring down the RH inner guard.
The EFI loom was finished with a header wrap covering (local speed shop supplied), and that has kept that loom soft and pliable since 1994.
This snap shows the basics of the engine bay, and some of the wiring is visible. I took no snaps back then, no thought of the future.
Attachment 148152
I never gave heat range etc any thought, just knew it needed doing, and simply did it.
I did both mine pre computer days etc.
I simply purchased a roll of 3mm Trailer wiring, Wurth brand, of the 7 core spec. That gave me 7 colours, goodo.
I also decided that the EFI loom was going to sit under the inlet manifolds, on top of the camcovers.
Being as I am different (some say special) I also rewired the engine bay, waaaaaay too many crispy wires to just do a patch job. That led to removing many electrickery items out of the engine bay, and the wiring done in such a fashion that the loom traversed the rear of the engine bay (up under the scuttle panel), and the required "mini" looms traveled from the rear to the front as needed, thus eliminating the under a/c fiasco, and lots of looped wiring down the RH inner guard.
The EFI loom was finished with a header wrap covering (local speed shop supplied), and that has kept that loom soft and pliable since 1994.
This snap shows the basics of the engine bay, and some of the wiring is visible. I took no snaps back then, no thought of the future.
Attachment 148152
I never gave heat range etc any thought, just knew it needed doing, and simply did it.
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#8
Join Date: Mar 2008
Location: Pacific Northwest USA
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Lots of work...so we made do with what we could find locally. And it usually worked just fine.
Nowadays it easier to treat ourselves and our cherished old Jags to glitzier, upgraded, higher-spec products. And there's nothing wrong with that.....except those things often have more 'feel good' benefit than tangible, real-world benefit. Injector wire is a great example. We buy the higher spec stuff because we can but (IMO) the most significant benefit comes from simply getting the harness elevated out of the Vee and out of direct contact with the engine.
Cheers
DD
#10
Join Date: Jul 2012
Location: Walnut Creek, California
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More than a few decades past, I collected wire for creating or fixing my critters. I found a "great" 'source in junked cars. Best stuff in the trunk Aka boot. Long lengths. Good condition. Great colors. Scratch wired at least a couple that way.
Decades later, a bunch from HF. Probably PVC insulated. I've used it on my Hot Rod ands later, my lump. So far just fine. On hooking up my efans, I used an all weather "trailer connector". Over kill, probably. But no issues for over a decade.
Carl
My mantra, keep the wires away from the heat. It seems
Decades later, a bunch from HF. Probably PVC insulated. I've used it on my Hot Rod ands later, my lump. So far just fine. On hooking up my efans, I used an all weather "trailer connector". Over kill, probably. But no issues for over a decade.
Carl
My mantra, keep the wires away from the heat. It seems
#11
Heat and PVC are not good bed pals, PVC wire in an engine bay will work, heck the XJS lasted 20-30 years, keep it away from the heat and it'll last longer.
TXL/GXL is better and used by the OEM's these days as the insulation is also thinner and the wire is lighter, you'd be surprised how heavy a complete wiring harness is for a new BMW or Merc.
TXL/GXL is better and used by the OEM's these days as the insulation is also thinner and the wire is lighter, you'd be surprised how heavy a complete wiring harness is for a new BMW or Merc.