teejaycrunk

i have an 84 z28 that came with 2 motors and a 700r4 trans out of a silverado. not a bad trade, or so i thought, the bone head cut the main trunk of wires feeding the back end of the cars electrical, so im assuming im going to have to pull the dash, rerun the wiring harnesses throughout the car and completely rewire it, besides "hopefully" finding another car that has one and ripping it out. where can i get one, and should i get one for the camaro or for the model of the truck i pull the 5.3l v8 out of?

BovineZro

iTrader: (11)

I'm sure some more qualified folks will weigh in eventually, but for starters:

What engines, and what vehicles were they pulled from? Are either of them original to the car (it sounds like one engine and the 700R4 are out of a truck)? How bad is the wiring harness in the car? Pictures would help!

I don't know much about the wiring in an 84 (mine's a 91) but I think that year only offered carburated and cross-fire injection. In either case, the factory wiring harness isn't going to work with a newer truck engine, so I'd look for some sort of conversion kit to modify the factory harness. Or, you might be able to find a pre-made harness for the engine/transmission combo you have.

Hawk's third gen has used factory wiring harnesses, but unless you're using the stock transmission and engine I don't know how much help that will be.

Hope this is helpful!

teejaycrunk

its all cut clean, and labeled but they are labeled with numbers and he didnt leave me with any info on how they were labeled. i figured if i went ahead and got a wiring harness for for the 5.3 motor im going to get used and rebuild, that i would get the plugs and connectors im looking for. even if i decide to toss aside this 700r4 and got with something like a turbo400. but all im seeing is some $40 harness from autozone. i dont think thats what im looking for.

teejaycrunk

ok for sake of argument lets say i go with an 03 silverado 5.3 from a junkyard for my build. i believe these would be the harnesses i would need to use instead of the stock one? would i be better off getting the harness from this website and rewiring everything or is it even needed? or is there an adaptor i should use for the motor and buy the stock wire trunk for the rest of the car, (if i even need to rewire it) car electrical is a pain to me. i can do the mechanical stuff and run the wires. but how the harnesses work and what to do here is beyond me
https://www.chevroletonlineparts.com..._id=&page_url=

Drew

iTrader: (58)

There's a bulkhead connector right at the firewall. Look between the two plugs and you'll see a single screw. Back out the screw and those stubs will pull out. One half is the headlight harness, the other goes to the engine and around to the computer back in the passenger's side of the dash.

Usually you can find decent uncut harnesses on Ebay, or hit the junkyard. Even if you just buy the terminals and wire, the headlight harness isn't THAT complicated. It could be built from scratch with all new materials pretty easily.

Edit: Actually looks like the headlight portion of the harness is fine. If you're going to go 5.3L you'll be building your own engine harness anyway. So you just need to decide which engine you're going to use and find a used harness or build a harness to fit.

BovineZro

iTrader: (11)

Yeah, I see what you mean - the engine harness part is basically gone. As Drew said, if you want to use a newer engine you'll need to make your own harness anyway (or maybe get the harness and ECM that come with that engine and splice it into that C100 connector).

If you haven't already found it, this site has a ton of the wiring diagrams and connector pinouts for our cars. That should at least help you figure out where the wires from that connector are supposed to go.

Tibo

iTrader: (15)

You would have to cut the harness when you do your own wiring harness for the 5.3 so it's not really a big deal. One tip I will give you is while you are doing all of your wiring work you should remedy the fuse block's power situation. The fuse block uses two ten gauge (or is it one ten gauge and one 12 gauge? I can't recall) wires at a length of nearly ten feet to feed the entire fuse block. This contributes to real voltage drop. You can up-pin the main feed wires on the interior side of the C100 and run them to a power stud on the interior. Run something like a six gauge wire (fused) to the power stud.

As far as the interior harness goes I would just head to the wrecking yard or classifieds here and grab an interior harness. The good part is that every interior wire harness began life as a fully optioned automatic transmission'd harness. Every harness is wired for power windows, power locks, fog lights, an automatic transmission, etc,. They just don't have the plug in portion that runs from a foot or two outside the fuse box to the accessory. So wiring them for additional items is easy. The trunk's electronics (hatch pull-down, tail lights, cargo lights) are connected via a body plug on the driver's side of the well under the plastics. So you may be able to just disconnect a tail light harness from a donor.

Drew

iTrader: (58)

Gotta disagree here. The interior or dash harness is specific to auto or 5spd in most cases. At least in the later cars, the only harnesses setup for both a 5spd and an auto are the TBI harnesses. The TPI and 3.1L harness don't have any of the auto transmission wiring when the car is a 5spd, and vice versa.

Tibo

iTrader: (15)

The interior harnesses for a 90-92 F-body with a manual transmission that I have come across were are also wired for an automatic. They had the plugs for the brake pedal for the TCC and the gear selector.

Drew

iTrader: (58)

Then you had harnesses from TBI cars. You can verify what I'm saying by looking in the Service Manual wiring diagrams, or just take my word for it.

teejaycrunk

so going based on what everyone here is saying you cant just plug the new (to me) 5.3L's harness into the connector on the firewall (c100?) im also assuming there is no conversion plug i can get to convert it from the newer 5.3l motor to connect the harness to this older car? (since its been said ill need to make my own harness) i dont like the idea of having a bunch of spliced wires for the car. is there a way to possibly cut the plug off of the 5.3L's harness and put the wires into the stock 84 z25's plug so i can just plug it in and be done with it? i may need to just have a buddy come over and help me with the wiring, its not really my thing.

but to answer a few other points mentioned here it was a bored 305 with an auto trans, idr what trans it was off the top of my head. its going to still be a auto trans, im not decided on a turbo 400 or beef up my current 400r4 that i have. i figured id start a new thread for that to get some opinions and info.

Drew

iTrader: (58)

No, you definitely won't be able to plug and play a LS into a thirdgen. The way you'll probably end up going, is to pare the 5.3L harness to it's significant circuits, and wire it to the thirdgen C100.



The C100 connectors come apart. The terminals can be removed by prying out the secondary locks, then using a pick to release the clip on each individual terminal. New terminals can be obtained from Mouser. Crimp a new terminal on your wire, slip it into the connector until it clicks, replace the lock, no splices required.

The alternative is to cut, solder, heatshrink, or but splice connectors, or wire nuts.... J/K about the wire nuts.

Here's a link to the Delphi catalog with all the connectors and terminals you'll ever need.
https://www.powerandsignal.com/docs/...%20Catalog.pdf

teejaycrunk

alright that makes sense, was looking for an easier way out or an adaptor. but if its never been made putting the 5.3 pins into the stock plug sounds like the best option in the long run. may as well buy a new plug and c100 since the plastic and rubber was broken when the previous owner tried to rip it off. thanks for the help everyone!

Drew

iTrader: (58)

From the pics, it looks like maybe just the dust covers are a bit chewed up. Once the connector assembly is apart you might find that it can just be cleaned and salvaged.

Tibo

iTrader: (15)

Wiring the C100 engine side isn't challenging. If you are removing the SRS and Emissions wiring it really becomes fairly straightforward. Ignition, gauges' signal(s), possibly some transmission wires, alt charging wire, coolant fan and fuel pump relay wires I think. Probably a few I've missed but again, nothing difficult.

Here is one for a 1990 for example:
http://www.austinthirdgen.org/mkport..._1990_C100.gif

teejaycrunk

im picking up the 5.3 tomorrow, is there any other items i should get with the motor besides the harness? like the ecm or other computers? or is something like that better to buy new. or is the stock ecm good enough an just needs to be tuned?

Tibo

iTrader: (15)

Grab the ecm for sure. All the wiring and sensors and covers. Manifolds. Air intake.

teejaycrunk

i said screw it, and got the whole motor and everything, i wont know what ill have clearance issues with unless i try right. thanks for the help, its very much appreciated.