Stock harness to stand alone rebuild - The 1947 - Present Chevrolet & GMC Truck Message Board Network

softballnrd27 · 02-18-2012, 06:44 AM

I am at the point in my harness rebuild where I need to wire all the external "stand-alone" parts of the harness. As most of you know I need to supply keyed 12v to 8 injectors, 2 coil banks, 2 O2 sensors, MAF, and 2 PCM connections. I have a 4 fuse block that will have 1 constant 12v and 3 keyed 12v fuses. I was thinking of running 1 fuse for the 8 injectors, 1 fuse with the MAF, O2 and Coils and then the last fuse for the 2 PCM feeds. Does that sound like a good plan or should I get another 4 fuse fuse block and break it down even more?

ls1nova71 · 02-18-2012, 02:47 PM

Alot of aftermarket harness companies bundle multiple like items together, but GM splits them up. Bundled together is easier and maybe a little cleaner looking, but on an original harness, if you blow one side of the engines injectors fuse, the engine will still limp by on the other side.
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usmcchevy · 02-18-2012, 04:46 PM

My notes in their full ugly glory. I kept all the factory fuses to make trouble shooting easier.

yossarian19 · 05-26-2012, 11:51 AM

I think using the factory fuse layout will make it easier to trouble shoot later on. I haven't gotten my hands on one of these harnesses yet, so I'm futon-quarterbacking you here. IMO, though, the more closely your final product mirror's a factory wiring diagram, the easier life is going to be later on and the more reliable your EFI is likely to be.

gringoloco · 05-26-2012, 01:01 PM

Listen to these guys. Do NOT set up your fuses like lt1swap.com. Use the factory layout and you'll be better off for the reasons mentioned above...
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68GMCCustom · 05-26-2012, 01:47 PM

my stand alone harness only has one main power feed (orange) and one switched (pink) feed. The red you see is the fuel pump lead and its relay. System has 2 grounds (1 main), 2 relays (one is fuel pumps), one 4 circuit fuse panel.

By hooking the orange to battery, and the pink to 12v switched, plus securing grounds... my harness is powered up.

softballnrd27 · 05-26-2012, 09:33 PM

I went this way:
Even injectors
odd injectors
even coils
odd coils
maf/o2 sensors
fuel pump
fans

02-18-2012, 06:44 AM	#1
softballnrd27 Always a work in progress Join Date: Jun 2007 Location: Harker Heights, TX Posts: 1,599	Stock harness to stand alone rebuild I am at the point in my harness rebuild where I need to wire all the external "stand-alone" parts of the harness. As most of you know I need to supply keyed 12v to 8 injectors, 2 coil banks, 2 O2 sensors, MAF, and 2 PCM connections. I have a 4 fuse block that will have 1 constant 12v and 3 keyed 12v fuses. I was thinking of running 1 fuse for the 8 injectors, 1 fuse with the MAF, O2 and Coils and then the last fuse for the 2 PCM feeds. Does that sound like a good plan or should I get another 4 fuse fuse block and break it down even more? __________________ USMC Retired Never trust a man who can't laugh at his own fart! 2010 Silverado Crew Cab 73 SWB 5.3/4l80e Build Thread: http://67-72chevytrucks.com/vboard/s...d.php?t=695168

02-18-2012, 02:47 PM	#2
ls1nova71 Registered User Join Date: Dec 2009 Location: Independence Mo Posts: 4,118	Re: Stock harness to stand alone rebuild Alot of aftermarket harness companies bundle multiple like items together, but GM splits them up. Bundled together is easier and maybe a little cleaner looking, but on an original harness, if you blow one side of the engines injectors fuse, the engine will still limp by on the other side. Posted via Mobile Device __________________ My '72 short bed build. http://www.ls1tech.com/forums/conver...6-0-4l80e.html 5.3 swap into my RUSTY '71 C10 http://ls1tech.com/forums/conversion...71-c-10-a.html

02-18-2012, 04:46 PM	#3
usmcchevy Has more rust than truck... Join Date: Apr 2005 Location: Ivanhoe, MN Posts: 2,421	Re: Stock harness to stand alone rebuild My notes in their full ugly glory. I kept all the factory fuses to make trouble shooting easier. __________________ 1972 Custom/10 SWB, 4.8/4l80e Build thread LSx Swap FAQ index

05-26-2012, 11:51 AM	#4
yossarian19 Registered User Join Date: Sep 2011 Location: Nevada City, CA Posts: 908	Re: Stock harness to stand alone rebuild I think using the factory fuse layout will make it easier to trouble shoot later on. I haven't gotten my hands on one of these harnesses yet, so I'm futon-quarterbacking you here. IMO, though, the more closely your final product mirror's a factory wiring diagram, the easier life is going to be later on and the more reliable your EFI is likely to be.

05-26-2012, 01:01 PM	#5
gringoloco A guy with a truck Join Date: Sep 2005 Location: Germany, for now Posts: 5,920	Re: Stock harness to stand alone rebuild Listen to these guys. Do NOT set up your fuses like lt1swap.com. Use the factory layout and you'll be better off for the reasons mentioned above... Posted via Mobile Device __________________ -Chris Instagram _elgringoloco_ '70 Short-Wide How to: Ruin a perfectly good C10 ‘70 Blazer ConversionHow To: Ruin a Perfectly Good 4wd '72 Highlander How To: Ruin a Perfectly Good K/5 (SOLD) '72 Blazer 2WD How to: Ruin a perfectly good Blazer (SOLD) '05 Yukon Daily Driven (not so stock) Yukon (SOLD) ‘07 Yukon Denali (daily) Members met list: SCOTI, darkhorse970, 67cheby, 67cheby'sGirl, klmore, porterbuilt, n2billet, Fastrucken, classicchev, Col Clank, GSFMECH, HuggerCST, Spray-Bomb, BACKYARD88, 5150, fine69, fatbass, smbrouss70, 65StreetCruiser, GAc10boy

05-26-2012, 01:47 PM	#6
68GMCCustom Truck and auto performance nut Join Date: Feb 2007 Location: McKinney,Texas Posts: 3,848	Re: Stock harness to stand alone rebuild my stand alone harness only has one main power feed (orange) and one switched (pink) feed. The red you see is the fuel pump lead and its relay. System has 2 grounds (1 main), 2 relays (one is fuel pumps), one 4 circuit fuse panel. By hooking the orange to battery, and the pink to 12v switched, plus securing grounds... my harness is powered up. __________________ Kurt - '68 GMC short step - NIB '09 LY6 6.0L crate motor w/mods, NIB '12 crate 4L85e w/billet 3k stall Circle D, 3.73 posi 12 bolt, DynaTech f-swap headers, 3/4 drop, handling mods, etc. - my toy '72 Chevy LWB C-10 Highlander - 350/350 ps/pb/tilt/ac - not original but close '06 Chevy TrailBlazerSS - LS2/4L70e - little black hot rod SUV - my DD '18 Kia Sorento - wife's econo-driver '95 Chevy S10 - reg cab shortbed, LS, 4.3, auto... my '68's powertrain and chassis build -links broken A surprise phase - carb to efi -links broken

05-26-2012, 09:33 PM	#7
softballnrd27 Always a work in progress Join Date: Jun 2007 Location: Harker Heights, TX Posts: 1,599	Re: Stock harness to stand alone rebuild I went this way: Even injectors odd injectors even coils odd coils maf/o2 sensors fuel pump fans __________________ USMC Retired Never trust a man who can't laugh at his own fart! 2010 Silverado Crew Cab 73 SWB 5.3/4l80e Build Thread: http://67-72chevytrucks.com/vboard/s...d.php?t=695168



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