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FAQ: How to wire Charge Harness Eg/Dc/Ek

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258K views 165 replies 49 participants last post by  Lotus  
#1 · (Edited by Moderator)
Hey guys. I'm currently in the process of swapping my Eg and I have been running into millions of questions. Thanks to the guys at k20a.org because they have the patience and ambition to always help someone out. So here is my turn to try and help someone. One of the things I couldn't wrap my head around was how to wire my charge harness for my eg. So I bought a charging harness and took it apart to break it down for everyone ;)

Rsx type s charge harness complete and labeled.

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Here is what the actual charge harness consists of. The rest of the plugs you see on the "harness" itself plug into the engine harness.

You need 3 wires, (I believe OEM uses 4 gauge)

1)One wire will go from the battery to the starter motor.​
2)Second wire will go from the battery to the fuse box​
3) Third wire will go from your stock fuse box to the alternator​

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Starter wire:

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Your positive wire should look something like the d-series stock harness. You need a 4 gauge wire to go from the Battery to the Starter and a 4 gauge wire from the Battery to the Fuse box. You can cut the d-series charge harness and crimp the power wire to the starter to the power wire for the starter on the k series charge harness to extend it. I plan to make a new one so I don't have to crimp.

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Alternator wire + Knock Sensor. Knock sensor will be on the end where the Starter Motor and Solenoid are.
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Don't forget the Ground Wire from the Battery to the Chassis
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Updated 2/14/12
So this is the summary:
  • 4 gauge wire (Battery to Starter)
  • 4 gauge wire (Battery to Fuse Box)
  • 4 gauge wire (Fuse Box to Alternator)
  • 2 gauge (Negative battery terminal to Chassis)

Diagram
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Updated 6-23-12
Couple of shots of the charge harness I made:

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These are the terminals I used for the FUSE BOX and the ALTERNATOR (I used 3, 2 for the FUSE BOX, and 1 for the ALTERNATOR)
Stinger 4 Gauge Ring Terminals (1/4") Hole ( 2 Pair )
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These are the terminals I used for the STARTER (I only need 1 but it was a pack of 2)
Monster 200 Crimpable Ring Terminals (4-gauge, 3/8-Inch Stud)
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This was the crimper I used
Hobart 770122 Lug Crimper
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Thanks k20a.org 🆙
 
#10 ·
#11 ·
I got a K20R swap (HMO) on the garage floor right now. Its going in a 92 EG. When you ran the charge harness.....you only extended the 4 gauge that goes from the starter to battery and battery to fuse box (which are very close to each other right?) So leave all the lines that plug into starter/alt/knock the length they came and run the 4 gauge to the battery (power and ground) over the trans and onto the firewall to the battery.....right? Or.....wrong :(
 
#12 ·
Im not extending the charge harness. I didnt want to crimp or solder 4 guage wire. I read on hondata its not recommended.
I took apart the charge harness to

1)remove the starter/altenator/knock sensor from it and plugged into the engine harness
2)run a 4 gauge wire (Battery to Starter)
run a 4 gauge wire (Battery to Fuse Box)
run a 4 gauge wire (Fuse Box to Alternator)
3) 2 guage ground from negative battery terminal to chassis

:up:
 
#13 ·
I apologize.....I meant new lines that are longer. I totally understand 'extending' the lines would be a poor decision. Therefore.....my word choice was poor :silly:

How did you route the alternator line? On the timing chain side?

And you found the correct fittings for the fuse box at a parts store?
 
#14 ·
fittings as in wire terminals/connectors? Im getting them online. The battery terminals you can get at pretty much any parts store. You can route the alternator cable on the timing side just make sure it wont contact the belt. And dont run it too tight as you have to compensate for engine movement. Dont want to snap any wiring :up:

Heres a couple fuse box terminals/connectors

Image


Image
 
#15 ·
So, by the connectors you just showed me. you are saying you didn't use connectors like OEM at the fuse box? They have those 90 degree bends.

EDIT: I was out of town and finally got to look at the way it connects tot he fuse box. Looks like regular crimp fittings will work well.

I am counting 20-24ft of 8 gauge all together for the starter and alternator to the fuse box and battery. Ouch.....incidentals are killing me!
 
P
#16 ·
In you pictures you swapped the starter and alternator power cables.

Power goes from starter to battery to fuse box
Alternator goes directly to fuse box
The cables pictured are already that way no need to cut or crimp any connectors.

What you showed as the positive battery terminal to starter is actually the battery ground cable. It needs to ground the battery to the fram and also the transmission housing. The transmission housing is where the starter is bolted in and where it want to get a good ground to run its motor. You can also wire from the transmission housing to the frame instead of the battery and provide this ground.

The starter to battery cable, imho, does not need any upgrade to larger cable. The 6 guage that honda uses obviously get the job done so larger between the starter and battery serves no purpose. However you could consider increasing the cable size on the section that runs from the battery to the fuse box, read below.

If you are running power from the battery for a stereo amp I question why you should not wire the alternator directly to the battery (like the starter cable) and use bigger wire. The way honda does it is run to the fuse box and then back out the fuse box up the starter cable to get to the battery. The weak link being the fuse box and it's connectors. But it would not hurt to run bigger wire from the alternator in any case.

In the rsx there is something called ELD that measures current being drawn from the system and I suppose that is why the alternator first runs to the fuse box.
 
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#17 ·
Im completely :confused:

Im sitting here charge harness in hand and mocked up... and see no reason why i have to cut anything. If you completely disassemble an RSX-S charge harness, and you plan to leave the battery and fusebox in the OEM location, there is NO need to cut or add to ANY wires.

Just mod the ends of each gold connector that goes into the fuse box per HR's instructions. The rest is plug and play. You can even use the cool red plastic cover for the positive terminal...
 
#18 ·
Ba82Ep3 said:
If you completely disassemble an RSX-S charge harness, and you plan to leave the battery and fusebox in the OEM location, there is NO need to cut or add to ANY wires.

Just mod the ends of each gold connector that goes into the fuse box per HR's instructions. The rest is plug and play. You can even use the cool red plastic cover for the positive terminal...
Click to expand...
I totally agree. I figured this out when I tried to run the two 6 gauge lines threw 2 runners in the IM and to the battery. I cut the ends and drilled some holes. Worked nicely.
 
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#21 ·
It was frustrating looking at what HR recommends and looking at the various setups on here to know what to do. I didnt get used harnesses, and i wanted to be SURE what i was doing before i cut anything. lol

It just makes sense to completely separate the charge harness like you did, then decide if you wanna shorten or lengthen anything according to your install. But its nice to definitely know there is a way you can complete the swap with an uncut charge or engine harness.

Regardless this site is awesome.. and a big thanks to all the effort put into these threads!! :up::up:
 
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#20 ·
On the EP idler bracket there is a bolt hole used for the throttle cable bracket. Im putting a bracket there to hold my 'charge harness' containing the alternator and the starter wires only. There will be another on the strut tower to hold it as well.

I did integrate my alternator/starter solenoid/knock sensor wires into the engine harness. There WAS too much slack there for my taste... but soldering/heatshrink/wrapping those is a much cleaner/easier task than big ol battery wire.

Image


Image
 
#26 ·
Yeah that looks right. You can also run just 1 wire like the Chasebays charge harness, that way you dont have to run the dist. block. Just go from the alternator to the starter with the power wire.

Like this, but have your battery in the trunk (you can use a different guage wire lol)
Image
 
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#29 ·
So you guys are talkin about one wire from the starter, to the alternator, to the battery, then to the fuse box. Im guessing you would need a jumper wire for both slots on the fuse box?

I dont see how that would be an issue as long as the alternator wire was the only one that was cut, meaning the starter wire was uncut from the starter to the battery, and the alternator wire was added to the starter wire (crimp, brazing, however).

I kinda like this idea. One less big ass wire...
 
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#32 ·
Cut a "U" shaped piece of flat plate brass and drill two holes in it to make a solid jumper from one fuse box terminal to the other. No need for a bulky jumper wire and additional wire work.

As far as starter wire size... 8 is bigger than 10... and going bigger is never bad... except over long runs of wire with limited amperage (resistance/voltage drop)... like going from trunk to bay.

---

I personally have two main grounds (not the suggested 3) and havent had any issues yet. Im using a 10 from the timing cover to the strut mount, and an 8 from a trans bolt near the starter to the drivers side frame rail. I think im gonna upgrade that one to a 4 and attach it from the front starter mount bolt to the same spot on the frame rail. Anyone have opinions?

I watch ELD load (sensor bar/KPro) when i make ground location and wire changes to get an idea if it makes a difference... two 8 versus one 8 ground on the trans didnt seem to make much difference on starter load... but i wanna be sure the starter doesnt try and ground through the timing cover ground.

:hmmm:
 
#34 ·
@Ba82Ep3 - i like that idea of the U shaped brass plate, but i dont know if i can get my hands on some, or where to get it for that matter. i think ill just use a small piece of 4 gauge wire with copper circle fitting's and keep it on the inside of the fuse box.

@CAFROG- for the 8 gauge grounds,are you saying drip some solder into the inside of the fitting then slide the wire in and heat it up? i was just going to crimp the wire down then solder. since its 8 gauge and cant use solder slugs like i can for 2 and 4 gauge.....
 
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#37 ·
screamin@9000rpms said:
@CAFROG- for the 8 gauge grounds,are you saying drip some solder into the inside of the fitting then slide the wire in and heat it up? i was just going to crimp the wire down then solder. since its 8 gauge and cant use solder slugs like i can for 2 and 4 gauge.....
Click to expand...
I put the fitting in a vise so it was a "cup" ready to be filled with solder. I heated up the fitting until solder would melt into the "cup"

Once it was over half full......and still hot.....I stuck the wire into the "cup" and held it until the solder became solid.

You may need to apply more solder but you make that decision.

Heat shrink over it and you will have a clean and strong connection.

In terms of 4-gauge fittings at the fuse box.....hard to find ones that small.
Thats why I said 6-Gauge but I simply used the RSX power wires and they worked really easy in my EG after I ground/cut them to fit.
 
#36 ·
one more thing, what kind of terminals are you guys using for the 4 gauge wire to the fuse box? all the ones i see look to big....
 
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#38 ·
o ok thats what i thought. im soldering them just like you described, just wanted to double check. as for 4 gauge copper lugs i found some with a 1/4 hole that will work.
 
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