Upgrades

[Jered1987]

Got my 86 k10 with 350/350 combo 14 bolt rear 10 bolt front 8 lug conversion,
255 85 16 elderado trailcutter tires. No ac. roll up windows.
Everything under the hood is a mess missing 90% of the ac stuff
Most of the emissions equipment is gone. Computer is gone? I guess, not hei ignition now? It's a half assed mess. Transfer case is leaking engine pans leaking probably transmission too. I'm wanting to do lots of upgrades in the future I'm wondering if I should just yank the transfer case transmission and engine completely and put in a new harness, I'm wanting to add lots of electrical, vintage air kit,led headlights, power windows, fuel injection ,sound system, car alarm, power locks, etc. I'm wanting to completely redo the interior too.

So my question is ultimately should I just yank everything and redo it?
And what harness? And what fuel injection kit for my 350? Thanks

[D13]

86 would not have computer.
The wiring harness you need would be dependent on the powertrain you are doing. If going to FI, then there are different set ups available, and each has its own electrical wants.

Best thing, make a list of what you want ohter than the drive train, then look at a full kit. A search here or in the electrical sectin should turn up some good caindates.

For the rest, realize that once you pull it apart, it takes more time and money then you think... but if you have something else to drive, and like working on it, a non-leaking powertrain is very satisfying.

[BHTH]

Originally Posted by D13

86 would not have computer.
The wiring harness you need would be dependent on the powertrain you are doing. If going to FI, then there are different set ups available, and each has its own electrical wants.

Best thing, make a list of what you want ohter than the drive train, then look at a full kit. A search here or in the electrical sectin should turn up some good caindates.

For the rest, realize that once you pull it apart, it takes more time and money then you think... but if you have something else to drive, and like working on it, a non-leaking powertrain is very satisfying.

I'm pretty sure any 86 would have a computer. It may have been yanked because an older powertrain was put it.

[aharper33]

I have an 86 and there is no computer on the truck.

[68longhorn]

86 is factory carb, 87 went tbi

My 86 had a esc module to the distributor

[LT7A]

Jered1987, if you want an honest opinion, I'll give you one. One thing that you'll see on here consistently is that very few of us have as much time for these trucks as we would like. What we expect to take days takes weeks. What we expect to take months, takes years. The builds that seem to move the quickest are the ones that the owner takes one thing apart at a time and fixes it. IE valve covers gaskets and done. Headlight connections and done. New radio and done.

All the stuff you want to add is pretty cool. I would recommend a two prong approach. Fix all the things you can, one by one with your current drivetrain combination. In the meantime, do research to see what you eventually want and how to go about it. Start collecting your parts while your truck is still running and you can enjoy it. The best way to decide what setup you want is to read up on what others have done. In my experience, pulling the drivetrain usually means that the vehicle sits for a long long time.

Good luck man, and enjoy. Start a build thread and keep us posted. If this isn't the answer kind of answer you're looking for, my apologies. I see that you have been a member for 9 months or so, and have approaching 70 posts. So my reply is based on having been at it a little longer. There're guys on here with a lot more experience than me though, so maybe some of them will chime in too.

[Dayton601]

I would second what LT7A said, fix one thing at a time, if its not running, get it to that point, then tackle the next item, you would be all over the place trying to do it all, I'm sure with each step there is someone here that can help if you run into problems,

Post a picture of it if possible,

[hatzie]

The 1986 electrical is still pretty simple because it's carbureted.
Don't believe people that say you "Must" replace the whole vehicle harness. Even if the engine bay harness is chopped up pretty bad there really aren't that many wires. Just break it down in bite sized chunks. "I'm only fixing this today" keeps the frustration at a minimum because you accomplished your goal. If you want to bite off another chunk once that's done that's fine just make sure you can finish so your ambition doesn't drop off the deep end.

Download the wiring diagrams and get familiar with them... or better yet find a set on paper. They look a lot more frightening than they are. The PDF is still nice to have because you can magnify and print areas of the diagrams. You'll notice the connector part numbers are right next to the connectors in the diagrams. Google the part number to find out what family it is.
I have a better scanner now so I may re-scan the 67-86 diagrams now that I can scan them at much higher res in one go. The old Fi5530C2 did a pretty nice job of the 87-93 11x17 scans but the longer pages weren't as clean for some reason.

GM didn't use a lot of different connector families on these trucks. Packard 56 & 59, Pak Con, Weatherpak, and some scattered Metripack connectors. You can buy terminals for all of these even if the shells are obsolete. I generally re-use the connector shells if they are in reasonable condition. Not only are they original so you can be gauranteed the fit... the terminals are cheap and the plastic shells cost several dollars each. Keeping that in mind the first tooling to invest in is a good set of extractors... Packards can generally be extracted with a #0 flat blade screwdriver and long narrow nose needle nose pliers... The rest generally are easier to service with the proper extractor.

Usually the cab wiring is in OK condition other than whatever mess the PO made in the radio area. You can usually pull that stuff out and clean up that mess fairly easily.

In the engine bay...
The tail lamps and the fuel sender wiring usually get the crap beat out of them. Thankfully we're only talking about Five wires. 1986 already has the Weatherpak 2x2 plug on the rear end of the harness. Just replace all four wires with new Packard 56 terminals for the firewall plug and Weatherpak terminals and seals for the rear. The sender wire may or may not need attention... It's one wire.

The HEI coil has one fat wire. If the PO removed ESC don't bother with putting it back. Get the earlier distributor and go. If you can find a used GM smallblock HEI unit you can rebuild it by installing Delco Professional internals for around the price of a crappy Chinese ripoff and yours' will actually work and hang together.

You usually only have two sensors on a gasoline engine... Oil and Temp. That's just two wires usually Tan and Dark Green.

The alternator has three wires. The Charge wire and the exciter wiring. Only one runs to the firewall disconnect plug. The other two go to the Junction stud and the Starter.

The starter usually has the big fat BAT cable, a Purple Crank wire, and one or two fusible links.

AC is where it starts to get mildly exciting til you realize the HVAC is a sub-harness that can be disconnected, pulled out, and re-worked or replaced from a donor. The AC sub-harness is listed in its' own pane in the wiring diagrams. Look for RPO C60 in the wiring diagrams. You can blow that pane up and print just that sub-harness diagram on an 8.5x11 page with numbering etc that anyone can read.

Lighting is two sub-harnesses. Forward and rear are even in thier own connector in the multi-section bulkhead disconnect so you can separate them, pull the harness, repair or re-fab and re-install.

The wiper wiring looks scary til you realize, again, it's only a few wires. Usually these are Pak Con or Packard plugs on the motor and a Packard plug on the washer pump running back to the Packards on the firewall plug.

I'd replace the damaged wiring first then carefully plan out and add what you want.

Complete sub-harnesses can be re-fabbed on a cheap cork board with thumb tacks at the ends and breakout points. Or on a piece of plywood with fine gauge finish nails.
Get the super tiny wire ties at Home Depot to corral unruly new wiring, that's taken a set coiled on the spool, at the breakout points and several points in between. Leave three or so extra inches at each termination point. I usually end up with the wires at the connectors around 1/2" longer than the original damaged piece. If there's a place that looks like you'd benefit from some extra make a note and add it. Nothing says you must make the harness exactly the same length as the factory piece. Generally you don't want it shorter anywhere but a little bit longer doesn't usually hurt.

[gmachinz]

Just to add, a lot of the pack con shells are obsolete now and cant be found or cant be bought with quantities under 2000 for example. The aftermarket is late to the game on these trucks wiring wise.

[hatzie]

Originally Posted by gmachinz

Just to add, a lot of the pack con shells are obsolete now and cant be found or cant be bought with quantities under 2000 for example. The aftermarket is late to the game on these trucks wiring wise.

Yup.

Terminals are cheap and available. Only some shells are.

That's why you need to be careful of the shells. Delphi extractors or good quality aftermatket like SIR 9024 & 9025.