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I got my swap done last week, made my own harness with no engine lights. Didn't want to wait and spent the $350. Decide to do a write-up for those who are willing to do their own. If you can read the Hondata schematic
, you won't have any problem.

If you can get the sub harness from the RSX to use the connectors, C101 and the E-plug. I was able to get a 02 civic sub harness, used the stock relays, but you can use universal relay, but on the civic connector it's was missing some wires that needed to be added.

So, basically you'll need the C101 to connect to the engine harness, 3 relays and E-plug to ecu. The Hondata schematic is really good, just missing the 2nd O2 and DLC which is in the manual.


For the EG
Once you get the harness made up with the 3 relays.
Unplug the main relay which you don't need anymore. Jump wires 7 and 8, this will let you tap the output from the Fuel pump relay to A7 at the stock ecu harness. Jump 3 to 5, this will let you tap the Ign signal at A25 on the stock ecu harness.

A7 for fuel pump
A25 for Ign signal
D1 for Batt+ (make sure to change the fuse under the hood from 7.5amps to 30amps.)

Main relay looks like this.

- - - -
8 6 - 2
- - - -
7 5 3 1

1 Bat+
2 GRN
3 A25
5 IGN
6 St switch
7 Fuel Pump
8 A7

These are the wires I tapped.

E15 - ELD to D10 on stock ecu harness
E22 - Brake Switch D22 on stock ecu harness
E26 - RPM to gauge
E31 - MIL to A13 on stock ecu harness

Engine Harness

3 - VSS - tap it to gauge
7 - FanC -- A12 on stock ecu harness
8 - Alt-L -- A16 on stock ecu harness
16 - Starter -- I solder it to the ignition or tap it to starter wire
18 - Oil pressure -- tap it to gauge

DLC Pin Out
The pinout at the diagnostic port is as follows:
pin 4 (BLK) = chassis ground
pin 5 (BRN/YEL) = LG3 logic ground from ECU pin E3
pin 7 (LT BLU) = "K-Line" (2-way OBDII serial communications line) to ECU pin E23
pin 9 (BRN) = SCS (Service Check Signal) line to ECU pin E29 <--
pin 12 (RED/WHT) = write-enable signal to ECU pin E30 (for rewriting the ECU)
pin 14 (GRAY) = +5V from immobilizer control unit pin 3 (probably for rewriting immobilizer codes)
pin 16 (WHT/RED) = +12V battery voltage (from #9 BACKUP fuse 7.5A)

so another way to do it would be to ground ECU pin E29, and then you should get the CEL flash code as described in the above article.

2nd O2 Pinout
O2 sensor plug
1 2
3 4

1 -- E2 - (WHT/RED) SHO2S
2 -- E4 - PNK SG3
3 -- To A/R Relay (same as the Primary)
4 -- E6 - BLK/WHT SO2SHTCR

Temp and fan switch needs to be wired.

Good luck and make sure to double check. PM if you have any ?
 

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Discussion Starter #5
Tommy Ten said:
thanks alot...I am going to try this and maybe post up some pics to have a better understanding
Hey, good luck. Once, you build one, you'll fully understand the wiring. Let me know if you need any help. :up:
 

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I took the general plans for this EG harness and made an effort to adapt it to a 4g EF/CRX. I'm looking for feedback from others, and perhaps someone to check it over for errors........so chime in. It's not tested, or even finished.

***see below for updated image/schematic***

I'm unsure of the VSS tap to the speedo. The stock EF cluster would be providing the stock ecu with a VSS signal. Is that what the RSX ecu is looking for, and is the EF signal compatible?

I'm unsure of whether or not the EF main relay terminals are exactly the same as the EG main relay terminals (which I assumed). Can anyone confirm, offhand, that they are?

I'm thinking that fanC to ecu plug position B4 is redundant, since the fan wiring on the EF is stand alone. Confirm?

I'm thinking that the following wiring/circuit items will need to be stripped from the standard EF engine harness:

-back up light wiring
-coolant temp for cluster
-coolant fan wiring

Am I missing anything there?
 

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"I'm unsure of the VSS tap to the speedo. The stock EF cluster would be providing the stock ecu with a VSS signal. Is that what the RSX ecu is looking for, and is the EF signal compatible?"

yes tapping the vss from the cluster will work.
 

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blackwagon said:
"I'm unsure of the VSS tap to the speedo. The stock EF cluster would be providing the stock ecu with a VSS signal. Is that what the RSX ecu is looking for, and is the EF signal compatible?"

yes tapping the vss from the cluster will work.
Thanks for that - one less thing to figure out.:up:

I checked out the helms manual regarding the main relay terminal functions. The ones jumpered turned out to be the same, although the main relay on the EF isn't exactly the same as on the EG. I updated the schematic to include the correct EF main relay terminal description/pinout.

****see update below*******

Does anyone have any information about the back up light wiring. Meaning where it comes off of the engine harness (through the passenger side firewall plugs?)?

Also, what about the fan/thermoswitch wiring. I'm thinking it should be straight forward to pull out of the engine harness. I was wondering why some of the manufacturer harnesses have two ground tabs (little rings to bolt to chassis for ground). I thought the fan wiring circuit only required one ground. Does anyone know more?

I took the info about using fanc w/ kpro from this thread:
http://www.k20a.org/forum/showthread.php?t=8430 ;
It outlines how to use the fanc pin to ground the switching side of a relay.

Here's a link for cluster pinouts - needed for tapping to guage cluster;

http://b16a.honda-perf.org/cluster.html

If someone could supply(sell) me an E plug, I'd make a harness and post up pics.

budget k swap FTW!!!!!!!!!

EDIT: I didn't make a note about wiring up ELD, since I'm in Canada. Position 15 on the E plug would need to be connected to pin B19 @ the ecu harness plugs if you have a car equipped with an ELD (U.S.).
 

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Added info for reverse light connection and some info specific to using harness with a type r ecu:



Still missing info on the fan wiring and guage temp guage pin location @ shock tower plug(although you could tap it directly to the cluster). I'll add it if i figure it out.
 

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NHB00R said:
sickining thread!!! :up: :up: for making your own harness


I just got my C101 plug and the DLC hasn't arrived yet, but it's mostly finished. I didn't connect the EF driverside (edit: meant passenger side) shock tower plug(s) yet - will splice them in during install (once I have all swap parts). The second O2 isn't wired (kpro). Worth it for the cost savings and the understanding gained as to how the engine interfaces with your car electrically - in case of future troubleshooting issues.

The second terminal ring (@ the e plug) is for the DLC ground. The fan switch wiring is independant of the swap harness - just ground one end of the plug and tap the other end at the appropriate shock tower plug (which one depends on model) to complete the fan switch cooling circuit. The same goes for the guage coolant temperature circuit.

Thanks to the OP. This helped me save some $$:dance:
 
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