Ok, so I took the engine out of my 89 RS with the intention of replacing the engine harness due to spliced wires shorting out from the previous owner. SO the engine is fully rebuilt and ready to go in. Now that i have started on the harness I quickly decided that it is going to be a nasty project. Does anyone have any suggestions or ideas on the best way to go about doing this? I don't even know where to start. Any help is greatly appreciated.

 

What induction type is on there now and what are you doing with it

 

It was a bone stock 305 TBI. Now I have a Comp Cams 08-500-8 roller cam and all new internals. But the previous owner had spliced circuits together to keep it running and its a mess, so i pulled a donor engine and harness out of an identical year/options Camaro from the junk yard and that is what is going in now. Just overwhelmed by all of the wires.

 

Stock, the harness wraps around the engine several times. Its a pain. Thats the main reason I tell people to pull the engine with the harness still attached

To get the harness off, the starter needs to be dropped, accessories stripped and lots of grunting to get the grounds off the rear of the cyl heads. The TCC connector on the trans isnt so bad once you actually get to it though, just getting your hand up in there is the trick

The C100 is easy access, but pulling the EVAP stuff back up isnt so easy with the engine and brake lines in the way. ECM connectors and C207 require the pass inner fender to be removed. You have to twist the fender grommet just perfect or it wont fit by the HVAC box. If you cant get it, then unbolt the HVAC box

Dont forget, the HVAC harness, cruise harness and front light harness are separate from the engine harness and should not be removed unless they absolutely must be. The HVAC part is an even bigger PITA to get out than the engine harness with the engine still installed because its port is behind a cyl head. The light harness is a bear to remove anyways because GM routed it through several holes just barely big enough to fit the light sockets. Dont touch it unless you have to

 

Sorry, should have been more descriptive. I have the engine out right now, so the engine bay is empty. The old harness has to come out, new one goes in.

 

So it's hanging by the HVAC box and booster still? Cool, your job is all that much easier

 

I would like to think so. So you mentioned the lights, cruise and HVAC don't have to come out? Where do they disconnect? I need to replace all the wires surrounding the starter and battery terminals as the problem originated with a blown fusible link. I have already tried to route the new one through all of the small spaces for the lights. If I dont have to replace the front end then thats a relief.

 

ok, so I have started pulling the harness out and replacing wire for wire. Has anyone else ever had to do this? what a pain in the ***.

 

No reason to do it one wire at a time with a stock replacement harness

If you're building it for non stock EFI, then sure

 

Ok, i basically have the entire harness replaced except for the bunch of wires that go into the passenger wheel well. I am most likely going to have to solder all 41 connectinos because the harness we took out of the donor Camaro was cut right after the waterproof plug thinking that it was a detachable plug. Now that i realize that it isn't, I am just looking for advice on the best way to do this without ruining my harness. I have experience with soldering electrical connections from my RC car hobby days. Anyone have any advice?


And, Pocket, thank you for your help. I read a few of your posts on the third gen harness that helped a lot. Juts wanted to say

 

Solder and shrink tube, 41 seems like a lot, but its a drop in the bucket compared to a modern EFI harness

I prefer the pencil style iron for 18-20ga wires. Gun for 10-12ga

Practice on a few scrap wires before you dive into the actual harness to get your technique down

Glad the threads helped you