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Discussion Starter #22
I did a mini update on the Wiring section on the first page. I added a sensor/plug location for the transmission. I'll be doing a couple of these for the motor over the next couple days. Doesn't seem to be any really good layouts specifically for the K20z3 as of right now so decided to make one.

I also am working on an Excel spreadsheet labeling all the ECU wires from the K20a2 harness and what can be removed while doing this swap and using K-Pro so you can clean/tuck the harness if you want like I plan on doing.
 

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I did a mini update on the Wiring section on the first page. I added a sensor/plug location for the transmission. I'll be doing a couple of these for the motor over the next couple days. Doesn't seem to be any really good layouts specifically for the K20z3 as of right now so decided to make one.

I also am working on an Excel spreadsheet labeling all the ECU wires from the K20a2 harness and what can be removed while doing this swap and using K-Pro so you can clean/tuck the harness if you want like I plan on doing.
That's exactly what I need to know, been looking everywhere can't seem to find which plugs I need and which ones I don't.
 

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Discussion Starter #26
wow im doing the same swap in same car with s2k cluster and been DYING for a nice write up lol . do i still need a speedo heeler and stuff ?

btw you got that motor for DIRT lol , goodluck on everything ill deff be following
I don't have the motor in yet so I can't tell you for sure first hand. But from what others have said and with my extensive research on it you should NOT need a speedo healer if you wire the AP1 cluster correctly:
VSS to the Orange VSS Input wire at pin 3 on the 20 Pin AP1 Connector
AP1 Dash to the White/Green wire at pin 18 on the K20a2 "A Connector" at the ECU.

The only thing I haven't got to test yet is that I know the K20a2 ECU sends 12Volts to turn on the VSS. I believe the K20z3 VSS may only take 5Volts to turn on. So I'm going to take a reading off of one of my buddies SI's to see if it does only take 5V to turn on. If so we'll have to add in a voltage regulator on the sensor power wire to drop it down in voltage so we don't fry that bad boy out.

But as far as the coversion goes....there is no need for a speedohealer, should be as accurate as it can be just through the dash.

And thank you. I got the whole motorset cheap as hell so I deff couldn't pass it up. Its been a fun project too along the way!
 

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Discussion Starter #27 (Edited)
Check back in the wiring section for the completed sensor layout for the motor itself and what can/can't be removed from the K20a2 harness.

I also scored some RDX 410CC injectors and clips from a local guy for real cheap over the weekend. Wasn't going to swap them out but...eh what the hell.
 

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Check back in the wiring section for the completed sensor layout for the motor itself and what can/can't be removed from the K20a2 harness.

I also scored some RDX 410CC injectors and clips from a local guy for real cheap over the weekend. Wasn't going to swap them out but...eh what the hell.

This will help me so much thanks!!!
 

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Discussion Starter #29 (Edited)
VSS Wiring



The Vehicle Speed Sensor (VSS) is also different between motors. This is no doubt due to the difference in Vehicle Speed Sensors as a whole. The K20a2 uses a standard mechanically driven VSS unit that rides on a speed gear that is installed on the differential. The K20z3 uses a magnetic (sometimes referred to as High Frequency) VSS sensor that doesn't actually make physical contact with the gearset to tell speed. Again I plan on simply swapping over the harness connectors to make it work:

K20a2 VSS Connector:


K20z3 VSS Connector. Note the extra slot on the bottom right of the connector:


After some testing I've found 2 small differences between the two sensors that will need to be addressed:
1) The K20a2 VSS gets a 12V power signal from our Swap Harness via the Black/Yellow wire. The K20z3 VSS is turned on in the 06+ Civic SI's with a 5V trigger to the Yellow wire. We don't want to send the 12V to turn on our K20z3 VSS or we could risk frying the thing. However, we can use the 5V output from either ECU Pin "A20" or "A21" which are both 5V sensor outputs. This is either the Yellow/Blue or Yellow/Red wire. I used the Yellow/Blue wire which also runs out to the MAP sensor. So I bridged off of this wire in the harness where the MAP Power wire passes by the VSS harness. Props to Vvvtec's friend for coming up with this idea.
2)Wiring is different (looking at the wire side of the harness clip, clip on top, left to right):

K20a2 VSS
Pin 1: Black = Ground
Pin 2: Black/Yellow = 12V Ignition
Pin 3: White/Green = Signal

K20z3 VSS
Pin 1: Yellow = 5V Ignition
Pin 2: Black/White = Signal
Pin 3: Green/Black = Ground

So since I plan on switching the plugs on the harnesses so I don't have to alter the harness plug, I'll need to do a little wire switcheroo. So I'll be cutting the K20a2 connector off of the harness and attaching the K20z3 connector:

Yellow on K20z3 VSS connector to Yellow/Blue for 5V turn on in the K20a2 Harness
Black/White on the K20z3 VSS connector to White/Green in the K20a2 Harness
Green/Black on the K20z3 VSS connector to Black on the K20a2 Harness

Some people have just repinned this. Thats fine though I'm not sure yet how much (if at all) you may have to extend this harness if you go that route anyways since the K20a2 VSS Harness just needs to go to the top of the trans where as the K20z3 VSS is located on the front of the transmission.
 

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Discussion Starter #30
Additional large and bad ass update to the wiring section including pinnouts for connectors and where the wires go in the harness. Also some wire harness consolidation tricks.

Also did some testing on the VSS on my buddies 09 SI to get that all figured out with voltage changes. Ended up being to much info in the wiring section so I created another section just for the VSS.
 

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Discussion Starter #32
Wicked write up!!!!

So much to read so much info!
I may have missed it but I'm just wondering with the electronic VSS wired into the k20a2 harness with the voltage regulator does it provide the same signal as a mechanical VSS?
The signal is actually good if using the AP1 cluster (and possibly AP2, haven't really looked into it)

The voltage regulator will actually go on the line that provides turn on power to the sensor NOT the signal. The mechanical VSS takes 12v to turn on, the magnetic only needs 5v to turn on. The cluster will be the thing changing the signal voltage level.
 

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Discussion Starter #33 (Edited)
Harness De-Pinning:
Couldn't find a very good write up on this but its very easy, so I figured I'd add it in. Every plug I've got to on the harness has this same basic release procedure be it 2 or 3 terminal. If I find a different plug I'll add it too.

1) Locate the release notch cut into the top of the inner housing piece.


2) By far the easiest tool to remove this with in my possetion was a Hook Pick Tool. Just simply stick the end of it in the notch and rotate the handle away from you to pull out the inner housing piece.


3) With the inner housing removed, you can look into the pins. There is a release tab holding the terminal into the harness plug on the opposite side from the outter harness release you use to release the harness plug from the sensor. Insert something small like a clothes pin in between the terminal and this release tab. I have marked this with the straight line in the picture below.


4) With the terminal removed from the housing you can more clearly see this release tab now resting further down into the hole where the terminal was pulled from.


5) While looking at the terminal you can clearly see how the whole operation works. The release tab holds the terminal into the housing by resting in this open area towards the back of the terminal itself. So our goal was to lift the release tab out of this space at the back of the terminal.


Found a couple other pin locks while working through the rest of the harness. I've done a couple of these now and this one was by far the easiest. Had the whole thing de-pinned in about 20 minutes. It was the first one i've done that was more fun than nerve racking. But heres the other 2 types of pin locks I found:

Large 6 Pin Lower Harness Connector
This has upper and lower locks. There is no piece that needs removed prior to de-pinning. Just simply release the top and bottom locks at the same time and pull out. I was able to just use what was in reach (de-pinning tool and a clothes pin)


Starter Power Wire
I believe I have this labled. Haven't really had the starter mounted and frankly didn't do research on it yet because I'm sure it'll be obvious when I lay the harness on the engine. But this ones pretty self explanitory too. Starts out like this with a black/white 16 or 14 gauge wire in it (going on memory).

Pop the ass end of the plug open:

The release is on the clip side of the plug.


Pardon my mangled magnified hand. But those of us here all understand how messed up you get while actually working on a car yourself instead of paying someone else to do it all for you.
 

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heya, spoke to a friend of mine last night. The TPS voltage is 5v, yellow with blue stripe
Just another option.

I'm about to check voltages on my setup, extend and repin the connectors and see if my speed sensor works.

Ek4 VTi-R/ SiR - K24a3 with the Tsx transmission, magnetic speed sensor.
02-04 K20a engine harness, repinned at the ECU connectors to suit the 05 - 06 haltech (k20z3) platinum plug in pro.
 

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Discussion Starter #35
heya, spoke to a friend of mine last night. The TPS voltage is 5v, yellow with blue stripe
Just another option.

I'm about to check voltages on my setup, extend and repin the connectors and see if my speed sensor works.

Ek4 VTi-R/ SiR - K24a3 with the Tsx transmission, magnetic speed sensor.
02-04 K20a engine harness, repinned at the ECU connectors to suit the 05 - 06 haltech (k20z3) platinum plug in pro.
Ah yes I see what you're saying. Run power to it from ECU pin "A20" and "A21" which are the 5V VCC1 and VCC2 outputs to sensors. Absolutely makes more sense than buying and wiring in an additional piece. Good thinking. I'll edit my past posts on here that that is mentioned in to reflect this new found revalation! haha. Thanks!
 

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Discussion Starter #38
Glad to hear! That's why I'm doing it.

I notice you're from WV. If you or anyone else reading this wants to get together next summer we should have a little k20a meet somewhere!
 
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