Basically, I have a ton of cracks in the under-intake wires on my engine harness. I already need to replace several fuel injector clips, the BAC clip, the water temp clip (under alt) and the alt plug. I did the s5 intake swap (my car is early s4 with resistor pack) and am putting on an fd alt so I already need to move around the BAC plug and put on a new alt plug. I also did the full emmissions removal so I now have a number of extra plugs for the emmissions solenoids.
What I am planning on doing is running all new wires for the fuel injector clips from right after the resistor pack. I also plan on cutting off the part that goes towards the emmisions solenoids and re-routing the neccessary wires closer to where they actually go.

My question is this: is there anything special I need to know about any of these wires? Are any of them shielded or anything weird like that?
Thanks in advance.

 

Only sheilded wires in the stock harness would be the CAS trigger wires.

Really........if you do this wire by wire........it'll be alot of work but not overly complex or impossible by any means. Good luck

 

It doesn't seem like it should be too hard. I am just going to dive in with a meter and find out which is which. I've already done a good bit trying to trouble shoot an injector issue (turns out I got the water temp sensor and rear primary injector clip mixed up) so I know pretty much how it works.
I'm sure it will take some time, but I want to do this right. Whenever I move one of the primary injector wires the casing breaks since it is totally hard from heat damage. I'm gonna be really pissed off if I do all this work to get the car running then I find out one of the fuel injector wires is shorting out on something.

 

You actually have cracks in the wires or just cracks in the outer insulation of the harness? Problems with the wires in the harness is very rare because they're very well protected by that outer insulation. It takes the damage instead of the wires, and it can easily be repaired.

 

well if you Want to do it,Go for it..MY Take on it:I would get Another Half Assed Harness.REWIRE That one,THEN replace yours..Reason?:no down time!..

 

Sorry, there is major cracking in the insulation around the wires, not the wires themselves. Cracks doesn't even begin to describe the outer insulation. For the record, this car has 240k miles on it.
As for the downtime, thats not a major issue. This car hasn't been running since August of '05. I kinda slapped stuff together to get it running and make sure that the engine is OK. I finally got it kinda running a few days ago (it has a large vac leak so it won't hold idle, but I can drive it around ok) so now I'm gonna tear the intake back off and fix everything correctly. I also have to order a few things (bolt, fuel sock, etc) so its not gonna be running for a little while anyway.
I'm just so damn excited that I will have my car running right in a week or two.

 

Wiring jobs take 10x as long as you'd think it would. I'd not be surprised if it took a week straight (or longer) of long days to re-do the whole harness.

 

I'm not re-doing the whole harness, I'm mainly just redoing the 8 fuel injector wires, and even that isn't going to be too major. I'm just gonna open up the harness right after the resistor pack and replace the 8 wires 1 by 1. I'm sure it will end up being more major than I'm thinking, but what the hell.

 

So peel the damaged stuff off and rewrap it.

Why? What's wrong with them? No continuity? High resistance?

 

Basically, the insulation is just really cracked and I'm nervous about it. Its also nearly impossible to get the insulation off to wire on the new injector clips. I basically have to whittle the insulation off, which doesn't do good things for the wires, not to mention being a huge PITA. Now that I think about it, I'm only going to do this for the primaries. The wires going to the secondaries are just fine.
Honestly, whether I do it or not depends on how much time I have after work this week. If I get really busy I'm just gonna say **** it, but I'm already going to have the intake off and everything disconnected anyway.
Thanks for all of the input guys, I like it when people join in because it helps me think about things.

 

I agree that this is a drastic and unnecssary step. You will probably be troubleshooting other stuff on this car. I know you feel like you halfassed it the first time around, but you don't need to do the opposite and spend too much time on one thing.

You can put shrink wrap on cracked wires in some cases. If you are having trouble stripping the end of a wire, there are wire strippers that automatically move the stripped insulation off. If you are having trouble getting wire to take solder, apply LIQUID soldering flux (you can get a huge supply of it for like $8 at Sears).

 

I know how to strip wires, etc, but the insulation is literally caked within the strands of the wires. I know it sounds crazy, but I kinda enjoy working on wiring....
Anyway, when I get the intake back off tomorrow, I'll take a look at it and see if it looks like way too much work.

 

So really the injector wiring is fine and this is just for looks...

Leave the existing insulation alone apart from what needs to be removed to get the new clips on. Get it as much dirt and oil off the outside as possible and wrap new insulation tape over everything you feel like. This will achieve the same results for a lot less work.

 

The knock sensor and O2 sensor wires are also shielded.

 

Thanks Aaron, I though I had seen that the O2 sensor was shielded. I have an s4 NA, so it doesn't even have a knock sensor, right?

Also, it would probably take less time and effort (and WAY less frustration) to just run the new wires than it would to strip off the insulation. I'm very adept at wiring, and I don't relish the thought of leaning over the car whittling away at baked on insulation. Again, I'll have to make sure once I have the intake off, but I should find out soon enough.

 

lol DO MINE? Its probably as bad as yours if not worse.

 

I don't come cheap

 

heh. i wish i had my electrical system in perfect shape. then i would just buy megasquirt

 

Or just buy a Megasquirt now, and make your own harness from scratch like I did.

I too enjoy wiring, and have seen the insulation melted into the wires on a few of mine too. I would guess it would take about 6 hours to rewire a majority of the wires, not including removal of the harness.

 

Thats what I'm gonna do when I get my megasquirt, but I don't have the time or money to do it right now. Plus I gotta get everything else on my car running right.

 

I dont know the first thing about wiring up an ems harness. SO. I wouldnt...

I will probably pay to get microtech installed

 

So you still haven't explained why you're replacing perfectly good wires rather than just rewrapping the harness. Since you're worried about time, effort and frustration...

 

I can't get the insulation off to replace the plugs, which is one of the main reasons I'm doing it in the first place. Well, technically I can get the insulation off, but most of the wire gets taken with it. I think it had about 2 or 3 strands left.
Anyway, this is getting put on hold for a while because the hard drive on my computer just died and I am going to be messing with that for a while. That and its raining.

 

I ended up deciding to run partially new wire to the primaries, and I really don't know what the big deal is. I undid the covering until about where the alt plug is since it was mostly falling off anyway. I cut off the emissions crap. Then I cut off the hard, brittle portions of the primary wires and re-routed them to where they actually needed to go instead of all over the place like when stock. I put on new connectors on both of the primaries as well as the secondaries. I have also almost finished replacing the connectors on the water thermo sensor (connector and wires broken), BAC (connector broken and needed relocating for s5 intake), and alternator (wires broken and too short.) So far I have maybe 3 hours invested the whole thing including removing the intake and the wiring harness and all of the work I have done. The last 45 minutes were spent on the extra connectors, and I estimate I will need about 30 minutes more to finish the wiring, then I will just need to re-wrap everything. I will post pics once I am finished.
Thank you to everyone who responded because even if I went against your advice, you helped me think about stuff I needed to do.
Now, I have one last question: What should I use to re-wrap the harness? I just seems like there has to be something better than electrical tape. Something that would help protect it from the heat would be excellent.

DISCLAIMER: Do not think that you can just tackle a project like this with no previous experience. I have lots of experience with wiring and soldering so other people might not find this as easy as I did.

 

I'd probably just rewrap the harness with several layers of quality electrical tape, but no doubt there are more specialised products available.