Wiring Questions

[RedDragun]

I'm helping a friend of mine (rccardude04 on here) wire up a CA18DET into a 1990 240sx Hatch, using a CA18DET engine harness and ecu. He bought the swap incomplete and the harness was FUBAR. So now we get the experience of rewiring all of it. The good news is alot of it was done properly. I am making this thread for all the questions I am sure we will have regarding this setup.

First we need to know the following:

The paperwork is vague and we have a couple of questions. We need a 12v source that is only on when the key has been turned. Is pin 45 what we are looking for? Pin 58 is an always on 12v source. We need the ignition on 12v for the resistor box (injectors) and the shared 12v on each coil pack itself (middle wire on the plugs that hook to the coils).

[sjbsuperman1425]

go into the stickies, download the FSM, and print the wiring diagrams out. that will give you what you need.

[RedDragun]

go into the stickies, download the FSM, and print the wiring diagrams out. that will give you what you need.

Sigh. That is what we are using. We have never done this before so we want to know if this is the correct pin for what we are wanting. We don't want an always on 12v connection, nor do we want a switched 12v connection that is ONLY on when the engine is cranking. Pin 45 looks like the right pin, we just want to make sure it is 12v Switched that remains on the entire time the car is on (key is turned to on).

[sjbsuperman1425]

for the coilpacks, i think you want a blue w/red stripe wire, and connect all the powers for the coilpacks to it..but im not 100% on that.

for the resistor box, i think the wire is red.

see if the pin(s) are that color..sorry i dont have the FSM open right now.

[float_6969]

Are you trying to feed power into the ECU, or get a switched power source out of the ECU? What are you ultimately trying to accomplish?

[RedDragun]

I am going to need to find a 12v switched source for the ecu, as well as connect to that source (from ecu or wherever I get the source for the ecu, doesn't matter) with the resistor box and the common positive on the coil packs.

I was wanting to make sure that pin 45 is the right pin on the ecu. I also need to know where to get my 12v switched source from on the car.

[float_6969]

Ok, yes, pin 45 should be a black wire w/ a red stripe. Yes, it is 12v+ switched power. In the stock configuration this power was received from the plug behind the battery. Be aware, that this wire also feeds power to many of the sensors and relays, so it is important to make sure this wire has all of it's proper connections?

Can I ask why you guys haven't tried to just source another harness?

[RedDragun]

What harnesses would we even buy? CA18DET Engine harness for sure, but the front harness with all the relays has been hacked up to, and so has the dash harness. The dash harness we have put back together already, and most of the engine sensors are wired.

Which plug are you speaking of that this +12v switched comes from? I don't know if any of the sensors are getting the +12v switched... Do they get it from the ecu (in pin 45, then to the sensors through the ecu) or do they get the power from the source before it reaches the ecu?

[CakeEater]

Source out a new (used) body harness, which is dead easy to do. Then find a CA engine harness, not so easy to do.

If you start with both un-hacked harness's you will be done the job imensly faster and you'll be free of the many electrical demons that can and most likely will occur.

[rccardude04]

Can I ask why you guys haven't tried to just source another harness?

The only CA18DET harness I could find was on eBay, and they wanted $345 for it. And I have a feeling we'd be about where we are now, with wires that were cut for the resistor box and ignition module. Then the body harness plug would be wrong, so we'd have to cut that. Then we'd get a new body harness and cut that so that it could be run to the engine harness (or wherever these things go), and would have exactly what we have now, but with having to re-plug every sensor on the car.

We're really close. Just need to make sure we're plugging the injectors and coils into the right +12v outputs on the ECU.

Our helper guy has a lot of experience wiring up cars. Just not really anything with nissan engines (he's a honda guy). The basics he's been very good with, but apparently hondas don't normally use the ignitor.

-Eric

[sjbsuperman1425]

did it look like this??





^^I believe those are for the ignitor



^^i think those are for the dropping resistor for the injectors.

idk if this helps or not, but thats the mess i had. i didn't do anything with the body harness and such, just did research and found the wires and connected them. Good Luck.

[RedDragun]

We have the dropping resistor all wired up and mounted (minus the switched +12v). The coil wires are labeled coming from the ecu, as are the separate firing wires from each coil (common positive needs to be hooked up still, and the common ground is done). We simply need an ignitor to route both sets of wires to and find our +12v switched ignition source from the body harness for the dropping resistor and common coil positive.

[sjbsuperman1425]

when you say the body harness, you mean the two plugs behind the battery tray correct?

[RedDragun]

You are correct.

[zero_gripS13]

i skimmed through and it seems u got most your info so im just going to post a tip.. a test light would answer all your questions, ground it tap the wire if it has power only when keys on then theres a wire that would work..

also heres some helpful links.

http://www.impactblue.org/cont...rnessh ... pinout.php

[sjbsuperman1425]

You are correct.

http://web.archive.org/web/200...oveka

^^follow the wiring guide to wire those plugs. take them off the KA engine harness

[RedDragun]

http://web.archive.org/web/200...oveka

^^follow the wiring guide to wire those plugs. take them off the KA engine harness

That's a spiffy link you got there!

The link mentions ka harness, are we talking about the harness from the ka as it would be if it were still plugged into the body harness but cut or if you were to cut the body harness? As is the connectors are plugged in but there is a length of wire coming from them. Should we cut the plugs off entirely from the body harness and use the chart, or do we use the "flying loom" which is part of the original ka engine harness (but I guess could be part of the ca18det harness but cut) which is plugged into the ka body harness?

I'm guessing because the pins are off on the plugs (but still plug togeher) that we should just use the wire colors on the body harness side of the connector.
Modified by RedDragun at 12:32 AM 8/1/2009

[sjbsuperman1425]

you want to take the KA Engine Harness and CUT those two plugs off leaving enough wiring attatched to them to solder wires from the CA harness too. i followed that guide to a "T" and i've never had any type of wiring problems with my CA yet. hope this helps!

Cheers!

[RedDragun]

We are hoping to get it wired the rest of the way tomorrow. We can't even find the maf plug anywhere. It's just gone. Any ideas where to look?

[RedDragun]

Okay we are almost done but there are many wires still that go nowhere. A few of these are for the maf but a couple didn't ohm to the ecu at all on the engine harness side.

Wires undone on the ka body harness:pinkblackbrownyellow/green yellow/bluebrownred/blue

wires undone on ca18 harness from ecuwhiteblackpin 7 yellow/redpin 55 pin 8pin 27pin 37pin 26

We also need to find a plug that will plug into the CA18DET MAF sensor, any ideas?

There is this random plug with one wire going to the drivers side and the other through the firewall:



Modified by RedDragun at 4:42 PM 8/3/2009
Modified by RedDragun at 8:33 PM 8/3/2009

[RedDragun]

I know what the wires that pin out from the ecu go to, but what about that weird connector? We are going at it tomorrow and hopefully we will get it started so any input would but appreciated. We have an ignitor now (thanks donator! (I don't know who)), but we need to find some connectors for it. We will be heading to a salvage yard to find something tomorrow morning. We also need to find a plug for the MAF.

[RedDragun]

Car is 99.9% wired up but we are still has is was confused on that plug pictured above.

[dash]

more stuff... simplified herehttp://lh4.ggpht.com/datsunlb1...13%25http://forum.ratsun.net/showthread.php?t=549http://www.frsport.com/SR20DET....html

[RedDragun]

Okay, so the two black wires with red stripes coming from the body harness are acting funny. When the key is not in the ignition there is zero voltage, but both wires are connected to a ground somewhere because they ohm out to the intake manifold/all grounds. When the key is turned to the on position (not cranking) there is +12v, BUT, the wires STILL ohm out to all grounds! WTF? Aren't these supposed to be ignition 12v only? I don't understand why it would be connected to a ground as well.

Also, the blue wire with red stripe coming from the dash harness, is it supposed to be ignition 12v? I know the coils have a shared 12v ignition which is also blue with a red stripe. We need help y'all

update: we bypassed the switched 12v and hooked the ecu, coil common positive and dropping resistor straght to 12v. Coil 1 fires. All the coil packs when plugged into coil plug 1 fire. When we hook a test lamp on to the coil 1 wire after the ignitor the light is on consant until we crank and then it flashes like it should. This doesn't work on the other three wires after the ignitor; well the light comes on continuous but doesn't flash when cranking the engine. We don't have a voltmeter with a fast enough refresh rate to test before the ignitor, and the lamp doesn't work either because of the lower voltage. Any way to check the wires coming from the ecu?

Modified by RedDragun at 1:08 PM 8/17/2009

further update: only cylinder 1 is getting spark and fuel. Ecu throws code 21. We checked the crank angle sensor and it seems to be ok, yet spinning by hand it still only fires spark and fuel on cylinder 1. The ecu isn't pulsing the other cylinders' coils either, just cylinder 1. We still need yo figure out what is up with our ignition +12v because it grounds with the key in any position.
Modified by RedDragun at 2:47 PM 8/17/2009

[RedDragun]

When turning the crank position sensor one full revolution coil one fires four times as does injector one.