Wiring diagram

[Sleeper_RPS13]

OK, I know this has been talked about many times in fragments and searching for Wiring Harness gives you so much info that you may as well be browsing the SR forum normally. I currently want to have my SR harness serviced but don't have the cash at hand. I am wanting to convert my blacktop S13 harness to work in my 93 240sx myself. I want to know EVERYTHING that needs to be done with this. Other than lengthening and shortening of wires, what else is there?

I have heard that the gauge cluster harness works fine with no modifications but others have said otherwise.

What is it on the KA harness that everyone needs so bad when servicing the SR harness.

Does the KA lower harness work fine with the SR? I have heard that the KA starter connection will fall off the SR starter.

Hopefully, if we get all the info on this, this will become a stickey.

[VitaminT]

Here is what I did. I do not know if this is standard, but my SR cranked on the first try and idles smoothly at 800. Note that this is for a redtop into a 93 hatch.

I swapped all sensors in the transmission and used the KA lower harness. It plugs in by the battery with no problems. Note that the harness does have some extra connectors along the transmission, but I just tucked these out of the way.

I next used the SR upper harness and routed it through the firewall. You will have to splice the interior dash plug from the KA harness to you SR harness. I just matched up all the colors that had mates and did not connect the rest.

I then unrapped some of the harness on the engine bay side to route the 3 plugs that run to the connectors behind the fusebox to that side of the car. This is a larger grey connector and a smaller red connector. I cut these two plugs from my KA harness as well and spliced them using Heavy Throttles' diagram and notes. The only other work that has to be done are the wires that run to the drivers side of the car. I extended the O2 sensor (3 wires), AC trigger (1 wire), PS (2 wires), MAFS (3 wires), and Ignitor (9 wires). The different connectors will have to be extended different lengths to reach their destination.

Hope all of this helps. Note that if you have a clip you can make an adapter harness for the interior and not have to cut the SR harness inside. I will try to attach a pic of what I am talking about later.

[charlotte240]

Sleeper is my buddy and we were trying to figure out if we can do this, but that definatly doesn't seem too bad. Thanks alot for the info dude.

[VitaminT]

I did my swap almost by myself. It is not that hard. I highly recomend making a checklist of things that need to be done. If you are getting a clip you can make notes when you remove the motor. I am very glad that I did it myself because now I know where alot of stuff is and if something tears up when I will know how to fix it.

[charlotte240]

Cool. I plan on working on the harness tonight when I get off work. I'll probably be on here asking more questions. Thanks.

[charlotte240]

I then unrapped some of the harness on the engine bay side to route the 3 plugs that run to the connectors behind the fusebox to that side of the car. This is a larger grey connector and a smaller red connector. I cut these two plugs from my KA harness as well and spliced them using Heavy Throttles' diagram and notes. The only other work that has to be done are the wires that run to the drivers side of the car. I extended the O2 sensor (3 wires), AC trigger (1 wire), PS (2 wires), MAFS (3 wires), and Ignitor (9 wires). The different connectors will have to be extended different lengths to reach their destination.

So I'm thinking I'm just going to lengthen all those wires 2.5-3 feet. Does that sound do-able?

Also, those two connectors that go by the battery area are on the front intake side of the engine compartment. (I'm not saying driver/passenger side because I'm converting the harness to a "different drivers side" so that would just cause confusion) On the SR harness, those two plugs are on the exhaust side of the engine harness. Should I just completely undo that and run it up with the TPS and then run it near the battery? or is it long enough to just bring it around the engine and along the radiator? On the SR harness, there is a third plug that isn't on the the KA harness. do I just not hook up that extra one?

[VitaminT]

2.5-3ft may be good, but I really don't know. I just ran the ecu plug through the firewall and then extended each plug a different length (i.e. O2 only had to be extended some while the MAFS, PS, AC had to be extended the most).

As far as the connectors by the battery, I did not have to extend them any just splice the two plugs from the KA harness. I just left the extra plug on the SR harness unused (all blue wires I think). I unrapped starting just about at that end so I could route the MAFS, PS, AC, O2 a little closer to the exhaust side, but did not have to lengthen the plugs by the batter. If you do it like I did you have the main stem that used to go behind the head kinda coiled up where it goes into the firewall.

I did not run the plugs up by the TPS and then over. I ran them along the intake side of the fender.

I will try to take some pics tomorrow, but it will probably be about this time tomorrow before I can post them.

[charlotte240]

Not a deal about the pics man. What you said made perfect sense. I get off work in an hour and will finish up the wiring hopefully. Thanks.

P.S. I havent gotten to the MAF, PS, and AC yet so I'll just do those as needed. I spent all my time today on the battery area clips and the ignitor.

[VitaminT]

I left my ignitor in the stock location, but kinda wish now that I had moved it. That would have saved me from extending 9 wires. That's 18 solders.

[GodzillaFan]

remember mafs, and o2 wires... some are shielded. you need to use shielded wire, and make sure the shielding is connected on both sides.

s13 wiring is incredibly easy if you have a good engine harness to start with.

[VitaminT]

What does the shielding do? I did not do this on mine. I heard about it, but could not find any shielded wire.

[GodzillaFan]

the signal coming off the maf and o2 is variable voltage, analog basically. the shielding is to keep those wires from picking up voltages from other wires and general EFI.

id go back and re-do those wires...

[VitaminT]

Hmm. I probably need to do that. Any idea on a place to get the wire?

[charlotte240]

Honestly, this sounds kind of stupid, but it works great for all sorts of wiring. If you get STP network cable its great. STP stands for Sheilded Twisted Pair. It's already got the sheilding and it is twisted in pairs then all four pairs are twisted together to further prevent crosstalk (signals interfering with each other) and other EMI (Electro Magnetic Interference). The individual wires are about 18 gauge so you can't use it for the thick ones, but it's great for little stuff (like the ignitor wires because they were the exact same gauge).

[charlotte240]

If you were to go to a store and ask for it, it would be "Sheilded CAT5-E cable"

[VitaminT]

Thanks for the tip. I am well aware of STP cat 5, but did not know if there was a single strand solution?

[charlotte240]

aluminum foil!

[VitaminT]

Haha, it will probably go on tonight.

[charlotte240]

Seriously though, I'm not telling anyone to get as ghetto as aluminum foil, but if you remember when we first did that strike on iraq we used alot of EMPs to fry their electronics. (that's Electro Magnetic Pulse) They protected alot of their equipment with aluminum foil. Now, if aluminum foil is good enough to supress a US military EMP, I think engine noise is childs play.

Of course, if I ever saw a bunch of aluminum foil under anybody's hood I'd give them a good scrote-kick (that's a kick to the scrotum) even if they were running a RB engine.

[Cyberkreig]

remember, if you un twist the wire ends more than one twist it looses some or all of its shideling ability and is no longer cat 5

[charlotte240]

Almost correct cyber. The twisting canceles cross-talk between the internal wires. The foil in the cladding provides the sheilding. But damn close if I do say so myself.

At least I'm not the only computer geek.:thinker

[VitaminT]

Haha, that is something you never think about. Cross talk on car wiring.

Renolds here I come.

[Cyberkreig]

Sorry, its been a few years =)

[IneedMoney]

this my be dumb but do you put the harness in before or after the motor is in?

[VitaminT]

I put mine in while on the motor. I really do not see a need to remove the harness because you don't have to fool with a couple of the plugs.

I don't think it really matters. I put it in with the motor and then took it off later. It's not like it has to be one or the other.

[sgpnismo]

Seriously though, I'm not telling anyone to get as ghetto as aluminum foil, but if you remember when we first did that strike on iraq we used alot of EMPs to fry their electronics. (that's Electro Magnetic Pulse) They protected alot of their equipment with aluminum foil. Now, if aluminum foil is good enough to supress a US military EMP, I think engine noise is childs play.

Of course, if I ever saw a bunch of aluminum foil under anybody's hood I'd give them a good scrote-kick (that's a kick to the scrotum) even if they were running a RB engine.

Ive got some heatwrap protecting my clutch master cyclinder and brake cyclinder from my exhaust manifold and it looks excatly like aluminum foil, it looks like **** but its saving a lot of my wiring that was melted before I had it, I had to buy a new wiring harness because i didn't have the heat wrap. Heat wrap=good,even if it looks like foil.

[midnightsliding]

if you did not do this Sheilding would it cause the car to run bad, like sputter?

[Neejay]

if you did not do this Sheilding would it cause the car to run bad, like sputter?

Ditto?

[sgpnismo]

I covered the clutch master cyclinder and brake cyclinder just because I cannot run a heatshield on my aftermarket exhaust manifold and just to be safe so the plastic cyclinder does not melt. I also wraped my 02 sensor wiring with it because on my other harness the 02 sensor wires got too close to the manifold and melted to it shorting out my entire harness. I just did it to not melt anything again.

[VitaminT]

They are talking about emi sheilding not heat shielding. And I have been running my SR for about a year now without any problems. No spuddering at all. Runs great and I didn't shield the MAFS or O2 wires.