ca18det wiring harness

[northerner]

I also followed the ECU pin diagram to find out for sure what each wire does on the brown and gray plugs. This is what I found

8 Pin grey plug :
Red/Silver band ECU 12v perm live PIN 58
Blue/Green silver band A/C relay *NOT USED*
Black/White silver band ECU eccs 12v switched PIN 109
Blue/Red Plug loom 12v switched (no pin)
Black/Red Ign power 12v switched PIN 45
White (shielded) Knock sensor (I will wire this in further towards the bulkhead)

8 Pin brown plug
Green/Yellow silver band A/C relay *NOT USED*
Black/Red silver band Eccs power 12v switched PIN 16
Green/Orange silver band Inhibitor relay *NOT USED*
Black/Purple Fuel pump relay PIN 18
(NOT SURE WHICH PIN ON THE FUEL PUMP RELAY)
Black/Yellow ***** Dont know what this is ???!!****
Brown/silver band O2 heater (my ECU plug does not have an 02 wire)

Now I think I have all these correct (if not then say!) but I need to know if my dodgy relay wiring is OK ? Can I run one Permanent Live/One switched 12v/One ground jumped through all the relays ???

[30psi]

I recall that some of the relays shared the shame power source even on the standard loom. You only need 3 relays though not 4.

I'd have to look back at my loom to remind myself what I did, but basically the 3 green relays plug in to the engine loom via the brown and grey plugs. You'll find the length of the wiring quite long, you could shorten these if you wanted.

I then found there were loose wires going to the relays for power, earth and switched ignition.

[northerner]

Once I'm ready for the transplant and the DET is in, I will shorten the wires accordingly. The 4th relay I put in there is for the Fuel pump or are you saying I could double it up on another ?

[30psi]

The 3 relays there are for the ECU, power transistor (the silver square box) and the fuel pump.

No need for another relay

[northerner]

Originally Posted by 30psi

The 3 relays there are for the ECU, power transistor (the silver square box) and the fuel pump.

No need for another relay

OK I will maybe use the space to tidy up my relays for radiator fans.

Any idea which pin on the relay I should use for the Fuel pump wire (Black/purple on the Brown plug). I take it this will be the fuel pump trigger wire from that comes from the ECU ???????

[30psi]

I'd have to check on a wiring diagram whether the ecu earths out the relay or puts power to it, but I think all you need to do is connecting the output from the relay to the fuel pump.

[northerner]

OK bud I'll await your reply. I had a look at the butchered loom today and cut off loads of multi-connectors to make the job neater. As the start signal on the s12 (black/yellow wire) is under the AFM, I will have to run the orange wire (white plug by the ecu plug) back down the loom to join it up.
I'm also wondering why Nissan put the knock sensor wire on the alternator wiring instead like the silvia on the Engine loom??? Maybe too much interference.

[northerner]

Originally Posted by 30psi

I'd have to check on a wiring diagram whether the ecu earths out the relay or puts power to it, but I think all you need to do is connecting the output from the relay to the fuel pump.

Having checked the S13 fuel pump relay, the black/purple wire is the Power/trigger wire that comes from the ECU. I now have to extend that from the white plug to the boot. I have now wired in several OE connectors to the larger (12v perm and switched wires and made up my three relays. It will simply be a case of plugging in the connectors when the engines in.
I do however have a couple of wires left to do :

1. Is Orange start signal wire from the White plug (by the ecu) that I have to re-route down to the Brown/grey connectors as the start signal on the S12 (8 pin under the AFM Black/yellow wire).
2. The Neutral switch. I know its the Green/Orange wire (brown plug) but I cant find the corresponding wire.