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Author Topic: Ca18det Wiring Instructions, Simplified  (Read 23047 times)

Offline Keith

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Ca18det Wiring Instructions, Simplified
« on: 01:03:48 PM / 26-Jun-07 »
Since I have been asked by several members from here and Nico on how to wire up the ca-det in a S12, I figured I would just start a new thread, instead of emailing the same info multiple times.
Most of this info I got on here by Gerry, and Indy from several different threads, and PM's, so hats off to them for all of their help and patience.  I'm basically just regurgitating whats already out there, and hopefully putting it in one simple thread.
With saying that............here we go!

Obviously you need to remove the ca18et/ ca20 and ECU loom/ ecu out of the S12.  I left all the other S12 wiring alone.....lower harness(tranny, starter, alt, oil sender wiring), and the coil/ transistor wiring, etc.  All you need to remove is from the ECU up to the 3 famous plugs near the maf location.
Next install the ca18det with the harness coiled up on the motor with everything connected.  Once you get the motor in and mounted you need to feed the harness up to the stock ecu location.  Most people just come across the motor and route it through the factory hole up by the maf location.  I didn't like how this looked so I did something a little different.  I drilled a hole using a hole saw and drilled through the inner fender by the clutch master cylinder then lined the hole with rubber tubing sliced to protect the wiring.  There is a lot more slack this way, and looks neater too.....


Once you get the harness up to the ecu location, your're ready for the wiring.

You need to buy four 4 pin relay, and 6 fuse holders with 10 amp fuses, or a small universal fuse box. I got mine from Radio Shack.

Next you need to find the 3 connectors on the S13 harness.  They'll be in the same location as the s12 plugs were at.  Follow the S13 harness from the ecu until you see 2 small canister shaped things with rubber caps. one has a yellow wire with a red stripe.  Find these then move along to the 3 connectors.  Unplug these and then you will have disconnected your engine/ ECU loom.

Now your ready to wire your relays/ fuses.

1st relay:  ECU Power

Pin 30- 12v constant on "Fused" power source
Pin 87- Black/ white wire from S13 harness
Pin 85- Ground
Pin 86- Ignition on source

2nd relay:  Ignition

Pin 30- 12v constant on "Fused" power source
Pin 87- Bigger black/ red wire spliced with bigger blue/ red wire from S13 harness
Pin 85- Ground
Pin 86 Ignition on source

3rd relay:  IACV

Pin 30- 12v constant on "Fused" power source
Pin 87- black/ yellow wire from S13 harness
Pin 85- Ground
Pin 86- Ignition on source

4th relay: Fuel pump

I re-wired mine completly using the following diagram:


Next
ECU relay- Wire the red/ black wire from the S13 harness to an ignition on source

ECU back-up power- Wire the red wire from the s13 harness to a 12v constant on "fused" power source

O2 sensor- Wire the brown wire from the S13 harness to an ignition on source

Next move on to the S12 lower harness.  I simply just plugged back in the tranny connectors from the s12 lower harness since I used the s12 b tranny.  
Oil sender- Use the S12 sender and S12 plug still connected to the s12 lower harness
Alt-  MK1: Snip off the s13 alt connectors, and snip off the s12 alt connectors.  Next splice on the s13 connectors onto the s12 lower harness, then plug onto the alt.
Alt-  MK2:  I was informed by Indy that the MK2 ca18et alt wiring is the same as the S13's, so all you have to do is just plug it back in.  Not sure on the mk2 ca20 alt wiring.
Starter-  I can't remember.....I think the S12 starter wiring from the lower harness, just plugged onto the s13 starter......I could be wrong though.

Next move to the ECU side of the S13 harness, which now should be laying in the foot well on the left side.
There should be a small white plug near the s13 ecu....part of the s13 harness.

You have to wire in the temp sensor.  You will need to remove the instrument cluster.
Find the blue/ black wire from the small white s13 plug.  connect a wire to it, and run it up behind the instrument cluster.  Next snip the purple/ white wire behind the cluster, which is the temp gauge signal wire, and connect the wire that you ran up to the cluster side of the purple/ white wire.
Next take off the ignition switch cover from around the steering column.  Find the yellow/ black wire at the back of the key switch....this is your starter signal.  Now find the orange wire from that small white plug on the S13 harness, where the temp signal wire came from.  Connect a wire to that orange wire, add a inline fuse, then run it up and splice it into the yellow/ black ignition wire at the back of the key switch.  DON'T CUT THIS WIRE, SPLICE IN THE NEW WIRE.
Next down by the s13 harness by the ecu should be atleast 1 black wire.  Add some wire to this, and ground it.  I had 3 total black wires, and grounded all 3.

Wiring the tach.  Follow the instructions within this thread..........
http://www.club-s12.org/forums/index.php?s...=14975&st=0

I did it slightly different....basically what I did was splice in the 4 diodes on the coil pack wiring near the ignitor, as per Gerry's instructions, then the opposite ends of the diodes I twisted all 4 together, crimped them into a butt connector, then crimped a long piece of wire in the other end of the same butt connector, routed it, and spliced in to the tach gauge signal wire, which is part of the S12 primary transistor wiring harness, down near the maf location.  If you removed ALL of your s12 wiring, then you'll have to tap into the back of the instrument cluster as described in the above link.

Your wiring is now complete!

*****To keep this thread from getting all jumbled up.....it will be locked.  If you see I need to make some corrections, or add something, please PM me, and I'll make the necessary changes.*****
« Last Edit: 09:42:46 AM / 30-Jun-07 by Keith »

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*1984 S12 Turbo* CA18DET swap * Custom top mount header & dump pipe * Mitsu Heavy Industries EVO III 16g turbo * Custom 3" turbo back exhaust with Magnaflow muffler * Front mount intercooler * Front mount oil cooler * Nismo fuel pressure regulator * Walbro 255 * DSM 450cc Injestors * Apexi Safc II * AEM Wide Band * AEM Tru Boost * Z32 MAF * Cometic head gasket * Centerforce Dual Friction clutch *  Tokico lowering springs * Owned since 1989 *

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