Wiring mess

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   I have a 1983 CJ7 that has been used and abused by previous owners. The wiring under the hood is a mess with vacant plugs and wires that seem to go nowhere. The distributor has been upgraded to an HEI unit by a previous owner. I recently replaced the 650 Holley 4 barrel carb with a Weber 32/36 with manual choke and this helped performance significantly. The stock ignition box is still connected  but one of the bundles of wires is connected to the under the dash computer harness. I removed the computer today and everything works. I want to clean up the rats' nest in the engine compartment. What wires can I remove? I recently installed a rebuilt 1979 258 engine.  There are no emission controls connected but all of the wiring is still under the hood. These wires were not connected to the engine I replaced.  I am assuming that I can remove the bundle of wires passing through the firewall from the computer but I'm not sure. Any advice is welcome.

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Sidney1921 Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Fan Joined: Sep/10/2017 Location: Rochester Status: Offline Points: 13	Post Options Post Reply Quote Sidney1921 Report Post Thanks(0) Quote Reply Topic: Wiring mess Posted: Aug/26/2018 at 4:00pm
	I have a 1983 CJ7 that has been used and abused by previous owners. The wiring under the hood is a mess with vacant plugs and wires that seem to go nowhere. The distributor has been upgraded to an HEI unit by a previous owner. I recently replaced the 650 Holley 4 barrel carb with a Weber 32/36 with manual choke and this helped performance significantly. The stock ignition box is still connected but one of the bundles of wires is connected to the under the dash computer harness. I removed the computer today and everything works. I want to clean up the rats' nest in the engine compartment. What wires can I remove? I recently installed a rebuilt 1979 258 engine. There are no emission controls connected but all of the wiring is still under the hood. These wires were not connected to the engine I replaced. I am assuming that I can remove the bundle of wires passing through the firewall from the computer but I'm not sure. Any advice is welcome.

knobbler Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Apprentice Joined: Sep/13/2015 Location: Seattle Status: Offline Points: 171	Post Options Post Reply Quote knobbler Report Post Thanks(0) Quote Reply Posted: Aug/27/2018 at 2:11am
	I'm not aware of any quick list of wires that can be deleted from the harness once the ECM has been bypassed and an HEI swap has been done, but if you get a wiring diagram for your year model, they can be traced out with a little study. Some things you may want to consider, though: if you're looking to completely remove the unnecessary wires, you're going to have to pull the harness apart. There's several points where wires related to the ignition system and such are spliced together, which you would need to cut out, remove the unwanted wires, then re-splice. Keep in mind that this is 35-year-old engine bay wiring, too. The insulation is likely hard and brittle in a lot of places, which can make it really difficult to work with. If the insulation has been cracking and allowing moisture and whatnot to wick its way into the stranded wire, you may also be looking at corroded copper strand. A simpler approach might be to make up a fresh harness. This can be done with a kit (I'd probably get one for a '79, to save the effort of having to separate out extra wiring that would come in the '83), or you can do it yourself. The kits tend to be kind of pricey, but if you factor in the time it takes to come up with a full list of the wire colors, gauges, and lengths needed, not to mention the cost of connectors and terminals, the two options end up being more or less a wash. If you decide to work with your existing harness, then you could get the '79 wiring diagram and do some comparison to the '83 diagram to get a better idea of what wires can be deleted that relate to the ECM. This might be a little challenging, since the diagram styles between those two periods is very different. When I was faced with a similar situation, I had to learn the options the hard way by trial and error taking me through all of them. If I were to recommend any, I'd say to go with the kit. Edited by knobbler - Aug/27/2018 at 2:15am

FSJunkie Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Jan/09/2011 Location: Flagstaff, AZ Status: Offline Points: 4742	Post Options Post Reply Quote FSJunkie Report Post Thanks(0) Quote Reply Posted: Aug/27/2018 at 3:30am
	The absolute worst thing that can happen to car wiring is people. Not rodents, not corrosion, not fire. People. You get people who don't understand wiring and don't want to understand wiring, but suddenly something simple will happen like their headlights will stop working and in an attempt to fix it they rip out all kinds of original wires, unbundle things, crosswire things, and finally run a hot wire from the battery to the light switch. Awful things people do. And you end up with this. Most of your wiring mess is probably the remains of the original computerized engine control system. If you have a conventional carburetor and distributor now, all those wires are unused and can go away. All the engine really needs now is the wiring for the ignition, alternator, temperature and oil pressure sensors, and any underhood options and accessories you have. Get a wiring diagram. Sort through it wire by wire. Figure out what stuff does and whether you need it. This isn't the sort of thing we can really describe or do for you here.
	1955 Packard 1966 Marlin 1972 Wagoneer 1973 Ambassador 1977 Hornet 1982 Concord D/L 1984 Eagle Limited

Sidney1921 Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Fan Joined: Sep/10/2017 Location: Rochester Status: Offline Points: 13	Post Options Post Reply Quote Sidney1921 Report Post Thanks(0) Quote Reply Posted: Aug/27/2018 at 8:35pm
	Thanks. I definitely DO NOT want to be the next guy to mess with the wiring. Before I do any thing more I'll check out the wiring diagrams in my Factory Shop Manual.

farna Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Moderator Lost Dealership Project Joined: Jul/08/2007 Location: South Carolina Status: Online Points: 19676	Post Options Post Reply Quote farna Report Post Thanks(0) Quote Reply Posted: Aug/28/2018 at 6:22am
	That's the best thing, though starting by removing that bundle from the old computer should be safe. Alternately pull it all and get a hot-rod wiring kit and rewire the whole thing. Not as hard as it sounds IF you're patient.
	Frank Swygert