Need Help: CA18DET Wiring at ECU Plug

[Zushi]

I'm working on a CA18DET swap into an s13 and have an engine harness that has had a modification made to it. Near the ECU plug there is a connector soldered in. It has 5 wires going into it.

Thick blue/red stripe
black
white
blue/white stripe
grey/red stripe

The grey/red stripe wire goes into the ecu plug and the rest of the wires go with the rest of the wires "towards the engine bay". There is no "other side" of the grey/red stripe wire coming "from the engine bay". I know there is no blue/red stripe wire that is supposed to come out of the ECU plug and that the blue/red stripe wire going over to the dash harness isn't a heavy gauge wire.

I'm not sure why that clip was soldered in but I need to erase it and bring the harness back to its original condition. Besides that clip there are no other mods made to the harness.

I am looking for any assistance in identifying these wires so that I can get them routed correctly. If anyone can help at all, please do. Thanks in advance!

[moso]

that looks like the white ecu to body plug for an s13 SOHC 89-90 body, if you have a s13 DOHC 91-94 body you will need to swap it out for the stock brown connector on your original ecu harness. the wires should go into the same locations, and have the same function as the stock s13 setup, check out my sig for a guide on the ka swap, the wires should be the same.

[Zushi]

yeh, i've got an 89 SOHC body. On the KA harness that I took out, there is no corresponding/matching plug in this location. I'm pretty sure this was a plug that was "custom-installed" for some purpose unknown. I can't find any reference to a thick blue/red strip wire near the ECU plug. I can tell that it was not custom run wire because it goes through all of the factory plastic wrapping and zip ties (these are all untouched).

[moso]

Its possible they were using this plug for some kind of piggyback system such as a SAFC. look for a pinout guide for the cadet ecu, you should be able to find one here on this site. If what you said is correct then its possible they just tapped the ecu at the grey/red wire just for reference voltage or ground. as far as the "other wires" are concerned, are they loomed in with the stock wires? they sure look factory color and markings, are they from the factory? its possible they depinned them from the ecu plug, are there empty slots in the ecu plug??

[Zushi]

ive got a pinout for the ca18det and its weird because the first thing i notice is that there is no blue/red stripe wire that goes to either the ecu plug or the dash wiring harness. so.. i dont know where that blue/red stripe wire is supposed to go. these are factory wires. they are definitely loomed in with the stock wires. i checked the pins and they are all as they are supposed to be. so its weird that there are no dangling wires. its weird too because the grey/red wire coming off of the ecu wires directly into the check connector and nowhere else..... hrrmmmm

[moso]

I would start unlooming the harness to see where those wires come from, its possible the PO just used old stock wires to splice in with giving the appearance of stock.

[Zushi]

its just weird because even if the stock wires were used....the blue/red stripe wire isn't supposed to be going to anywhere near the ECU plug i mean does everyone have a blue/red stripe wire there? if so...whats it connected to...

[moso]

your not picking up what im putting down. its possible the previous owner used wires scavenged from another factory wiring harness to wire in that plug. they "look" stock but are probably just remnant wires from another harness. unloom the harness you have and see where they originate.

[Zushi]

gotcha i was gonna just throw it in the car and see if it would work since everything else seems to be ok but... now i dont know if i could trust that logic haha

[moso]

i would be careful of that, if it was for say a turbo timer you may run into issues. just remember to zip tie the harness together as you unloom it to keep it from becoming a tangled mess, and to help keep its form. I would expect to find those "extra" wires tapped into stock wires upstream from the ecu plug.