Okay I am going to attempt to build my own stand alone harness. I sent one out to a company (I will not mention) to have done and it looks like crap. I have spent hours seperating it all and cleaning it up. On both of the harness' from the factory it has all of the grounds spliced together limiting me to re-routing wiring to make it look clean. (note I am ****) Can I cut those grounds and re-solder them, lengthing wires as I go along to clean up things?

On my personal harness I am going to attempt to do myself using the other one as a guide if I can figure out the mess of wires soldered together. There is one huge chunk of soldering of all the pink wires that I would like to redo too as it is limiting me to cleaning up the harness we paid to have done. What are your thougts on cleaning that up? Thanks in advance for your time whomever decides to chime in here.

 

I always suggest Current Performance, but since you want to do it yourself, check out lt1swap.com

it is kind of hard to understand his website, but once you figure it out it is cake. there are instructions on there for using the stock underhood fuse box, and for doing without the fusebox as well.

 

do you have a link for Current Performance? I keep looking at the ones on ebay but not sure on how good they will be.

 

The one that I have in my shop doesn't look too terribly complicated. Just hard to follow they way they jumbled up wiring and put about 30 pink wires in a huge solder connection that is coming apart.

If some one could say run all Pink wires to 12V+ keyed power, run blacks and black and white striped wires to ground, tie in the wires from rear o2 sensors to rear sensors by doing whatever. It just seems that everyone explains it so complicated.

 

Oh on a second note, I did read the sticky about using the factory fuse box but it's hard to do when your customer has spent ALOT of money with you and the engine looks like this.

 

Nice!
You can cut and lengthen the grounds within the harness. I did it to allow me to run the harness in a different fashion then stock. I know all the grounds end up together ultimately, but I cut one at a time and then lengthened and soldered back before cutting the next just to keep my head straight. I did that with the whole harness. All the pinks do end up going to keyed ign source, but not all on the same circuit like it sounds was done on your other harness.


Rob

 

Rob THANKS so much!! Now we are getting somewhere. I appreciate the information. Can you give me info on how to seperate the circuits maybe?

I am re-routing the entire harness I guess much like you did. Thanks again.

 

I will give you a few tips after modifying a couple myself-

-Take the pinks and group them by function. I think I used injection, ignition, transmission and misc and put them into a fuse block with a fuse for each circuit with like a 20 amp fuse for each one (you can get more precise fuse values from the wiring charts you download from Autozone's website if you want) Have a seperate fuse for the keep-alive circuit. You can get a nice fuse block from Waytek Wire.

-What the previous poster said about grounds - group them together and put them in a nice ring connector and ground them at the back of the engine block. Very tidy.

-Use a 40 amp relay to power up the switched power leads on the fuse panel

-Start with a factory harness. You are trying to boil the ocean with a new scratch harness. De-pin everything out of the harness you don't use. My experience with custom harenesses is that they don't always have all the functions you want, and it is better to start with a factory harness that has everything and delete what you don't want

-After you get the harness de-pinned and the wires stripped out you are not going to use, put it on the motor in the car. Bundle it every 6 inches with electrical tape (zip ties will drive you nuts) and get all your routings correct and establish a location for your fuse box. (note the factory routings suck, especially if you are using the truck harness - you can do better) There will be some wires that are way too long. You can coil them up in the harness or, if you are really ambitious, shorten them up. If you do shorten or lengthen any wires, use a butt connector that you solder the leads into and overwrap with shrink tube (also available from Waytek Wire). Crimp connectors are a sign of a sloppy job and the lazy way out IMHO.

-Overwrap the harness. You can use that cheesy corrugated stuff the factory uses if you are pinching pennys, but some stuff called FlexoF6 is ****. Where the overwrap ends, tape it with a good quality electrical tape- the 3M stuff is best. You can buy all this stuff at Waytek too.

-Use plenty of Adel clamps to locate the harness and sleeve it with heat resistant tube in places where it gets close to the exhaust.

I have one I just did that I could clean up a little and show you some pictures so you get the idea. I did it on a shoe-string budget so it is wrapped in the factory corregated tubing, but you could get the general idea. Let me know if you'd like pics posted.

-

 

http://www.currentperformance.com/

 

Allpro,
what fuse box are you going to use? What engine/pcm is that?
I used a current performance fuse box to make the harness standalone. I had a separate fused circuit for each bank of injectors, each bank of coils, PCM power, and a couple others I cannot remember [I am at work right now].

Depending on what fuse box you use, you will just have to designate switched power to each pink wire [or 2].

I am really happy with the Current Performance stand alone relay/fuse box here. With the directions of the current performance box and lt1swap.com I was able figure it all out.

Rob

 

I am doing a bit of the same but have the entire harness out of a F-body car. At this point I have the engine and engine bay harness cleaned up. I have removed the emissions, ABS, and Torque Management. The diameter of the wires going into the firewall on the drivers side has been cut in about half. The fuse boxes have been left alone and I also left the rear O2's on. I was thinking I may use those for a separate WBO2 connection for datalogging after I am all done. The last part is the body harness that will be probably the most work. I am planning on keeping the BCM and the stereo stuff just so the wirng is there. The engine to engine bay harness was reduced to 2 main connectors. The engine to body harness connections are only have 2 wires to be removed so far. Most of the wires are for the gauges and the fuel setup. I kept the canister purge system and I am adapting it to keep it stock because of previous experience of pressure buildup in the tank among other things. The BCM will have to have the door switches grounded and there will be a number of wires removed for the dash stuff along with the air bag on the passenger side wiring as the minimum. I have the factory column and the airbag will function along with the VATS, etc but they may not be removed. The only real wiring is the headlight switch to tie it into the new harness.

 

I am using a truck 2005-2006 PCM with DBW feature. It is a 2005-2006 truck harness as well. You are correct the routing of the truck harness is crap which is why I am re-routing everything. The problem is the vendor that did the conversion wiring bundled all of the pinks together in the middle of the harness and of course the crappy factory grounds budled make it difficult to re-route. The grounds are no problem, it is the pink +12V switched wires. I will post up a pic of what they used to power this thing up. They only wired in one relay for the fuel pump. From what I have seen most guys here there are at least 3 relays. Also where are you guys running the main pink wire +12V keyed ignition source to? The old wiring harness of the vehicle? Thanks you guys, I have learned more in just a few responses here then reading hours and hours!! I MEAN HOURS of reading!!

 

The pink wires are an easy fix. Just bundle all the ones that go to the ignition, injectors and transmission seperatly and then fuse them seperatly. They are easy to trace out with a meter - I usually grind one of the probes to a needle shape to fit into the connector.

Don't power anything off of a switched ignition source in the car - use it to close a relay that powers the bus on the fuse panel.

The output of the PCM for the fuel pump is a 12V signal to a relay to turn on your pump (not a ground to the relay)

The 12V power supply for the PCM I bundled with the transmission power just because I ran out of fuses on my panel. Ideally you'd like to have a seperate fuse for it.

The 12V keep alive wire is direct to the battery via a fuse

 

The 12volt keep alive wires (constant power) are the oranges ones am I correct? Wire these to the battery through a fuse correct?

Use the 12volt ignition source to power up a relay to power up all of the 12volt keyed pink wires right? Can I jump one relay to the next powering up ignition pinks on one fuse, coil pinks on another fuse, trans pinks on another fuse?

 

I forgot, one more question. On the emissions, what pinouts can I pull to clean up the wiring.
I am thinking about using a Livorsi boat GPS signaled speedometer so I can eliminate that as well, what pin? Is it tied in to the VSS on the trans? If it is should I leave it alone?
Cylinder head temp gauge (black and yellow) can I pull the pins and just run it straight to my gauges in the dash?
Sorry lot's of questions guys and I HAVE read thoroughly but everyone's swaps are different. Different harness and what not. Thanks again for all of the help.

 

Tie the GPS into the PCM speedo output as the VSS and GPS sampling will send a noisy signal to the PCM and mess with the traqns shifting...It happend to one of my customer cars....previous owner did the first install and I fix'd it.

You have a PM about schematics too.

 

Okay another part of the question as I go along and clean up these two wiring harness' I am working on.

Can I pull and delete the following wires and sensors from the motor and the PCM

Oil Level Sensor
BN
BLK/WHT

OIL PRESSURE
BK, GREY, WHITE (RUN SENSOR STRAIGHT TO GAUGE IN DASH)

A/C LOW PRESSURE SWITCH
D-BU, BLK (RUNNING AFTERMARKET VINTAGE AIR)

EVAP PURGE SOLENOID ON INTAKE?

REAR O2 SENSORS?

Also, I was thinking of running the pinks from the injectors to each other at the injectors themselves so I would only run one pink wire from each bank of injectors versus 4 down on each side to the fused additional panel I will be adding. Less clutter and cleaner looking I would think with less bundle and soldered connections in the harness. What are your thoughts on this?

 

Akno,

I will be running an antennae style GPS speedometer much as you would like a TOM TOM device where it shows you your speed as you drive and I wouldn't have to worry about tire size changes and gear changes to the PCM reprogram if I chose to change those items at a later date. Would I still get noise interference if I go that route. The antennae is tiny. You would barely notice it on my dash or A-pillar.

One more question, has anyone installed a push button start on these swaps and harness mods to say install a Corvette push button start? My boad buddies at Victory Marine showed me a new coded push button start button in aluminum that you have to punch in a 4 digit code to start the motor. No more locking your keys in the vehicle and just carry a door key with you. Or maybe put an external door lock code mechanism like the FURDS do and keyless entry as well. That would be cool on an old 72 chevy truck!!

 

Yes, you can remove the oil pressure, level, a/c pressure, and rear 02`s and EVAP purge.

 

I wouldn't. This is used to sample engine temperature for the PCM to run fans etc....put a sender in the passeneger head and run to aftermarket gauge...

T,