good luck with the wiring. been there, done that, and went back to stock. to be honest, without removing the a/c and countless other things, it's not really worth it. there's so much bullshit wiring on these cars lol. i remember when i went to the s13 ecu using scott's harness after my tune, i was able to de-pin like 75% of my ecu harness, and therefore, like 40-50% of my engine bay harness. it was cool, but i wouldn't touch it again unless it wasn't a DD and/or i was permanently removing it all.

the transmission harness is the easiest with the speed sensors. the engine harness takes care of itself since you have an SR harness (i had to gut my KA harness since all the obd-2 stuff was gone).

 

Hey Dan, I've heard a lot about you and maybe I've met you before idk. Shinmei2006 was telling me I should get in contact with you (since you're knowledgeable about S-chassis and you migrated to a MS3 as I understand it? also you're a tech guy, lol).

The main reason I'm doing this wiring crap is to move the fusebox since I want tubs (or to cut the front end off from the strut-towers entirely). For some reason I assumed my engine room harness was the OE 240sx harness adapted for the SR .. forgive my nubness (for I didn't do the swap, would've liked to of) but I thought it was a small task to modify the OE harness for the SR? However I know this motor has additional sensors and crap that the KA obviously doesn't, so it makes more sense to swap. I just assumed it was all stock the way it was loomed up and using all the factory mounts ... that and the fact that a lot of the connectors are spliced on.

The car is definitely not going to be daily driver (that's my new MS3's job heh), so in that regard I can take my time with it and get rid of a lot of unnecessary crap. Hopefully I haven't botched my introduction to you , I could use some knowledgable advise locally from time to time..



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Here's what I've done today so far, cut the engine room harness past the firewall grommet, taking note of similar wires using zip-ties for labels lol. I've found several unused connectors and relays so far to remove, and I've separated all the wires that are going to be leaving the cabin and going into the engine bay (lights, P/S sensor, Tripple Pressure Switch, A/C Comp, Greddy boost controller, Prosport water temp gauge, and the connectors to the lower engine harness ... I will be adding some wiring for an oil pressure sensor gauge and my innovative wideband, perhaps some more that I'm not thinking of):

 

you are a brave man for halfing that harness.

i don't know a ton about the SR harness swap since it's been so long, and i stuck with the KA. i hope you don't mean that they used a KA harness or something. I would assume it's an SR harness, there are a few small mods, but i know the swap is relatively easy.

the EL section of the FSM is your best friend. for shits and giggles, i just opened one to see. it depends on what you want to keep as far as accessories, but there are a lot of moving and hiding you can do. my brother has my old car, he is going to fix the front pans (i hacked em up good for IC piping), and he wants to relocate wiring too. i told him it's not worth it, but he might be able to get away with it since he's not tubbing.

Everything can be inside the cabin, but if you're keeping a lot of the accessories, the space gets limited unless you're willing to run a harness of wires to the trunk.

 

Yea I've been using the EL section from both the KA and SR FSMs lol. I haven't decided yet where I'm putting the box, either the glove compartment or passenger airbag area. I thought about the trunk but I think someday I'll have the interior stripped minus the dash. So I think trying to keep most of the wires up under the dash will be the cleanest.

Your old car was KA-T right?

What about your MS3, running a BT setup or anything fancy? I've never been in a modded one.

 

if you're not stripping out accessories yet, good luck fitting all that mess behind the dinky s14 glovebox (from what i remember). an interesting spot would be the passenger side airbag panel, if you can pry it up without it exploding into 300 pieces (old dry cracking dashes dont do well), there's some space under there once you ditch the airbags.

yes, i had a ka turbo.

basic bolt ons with the ms3. this year has been all 90-100K maintenance when money and time afford it. i'd like a few more mods (fuel pump, tmic, downpipe, ecu) but otherwise, it's fun enough. wish it got better mpg.

 

I will be removing some from the harness but not much. Mainly I will be removing 4.5~ feet of wires while shortening it. Just need enough length to run over to the passenger side. My dash is already out, the crash bar and passenger airbag are out. I'm going to modify the fusebox and attach it to the crash bar where the passenger airbag goes.

Im planning to do at least a 4 point cage behind the seats, get a couple of Bride's and harnesses.


I want to mod the MS3 but for the money I'd rather use it on the S14 or my Miata and just enjoy the MS3 as it is, I took it up to NC and Tn earlier this year and it was plenty of fun on those mountain roads!

Speaking of maintenance, how often do u clean the intake valves? I'm coming up on 12k miles (bought the car in March lol)

 

sounds like a plan. i know my brother may be planning it, but if i had the time, i would have loved to redesign the entire wiring system. new relays, one universal fuse panel, and everything in the car behind the dash with access through passenger airbag cover. it just would have taken a lot of wiring and time, which i never had. i would have used all white wiring aircraft style too, and it would have been properly soldered and labeled. would have been pretty sweet, but I realized quickly I needed a/c and PS back.

just be forewarned, OEM engine and body harnesses are not cheap, and it took me a few months to find used ones and even then they were from a 96, so i had to splice and dice the headlight connectors and a few other things. 97-98 harnesses are next to extinct from any car that isn't running, they either get damaged in accidents that send the cars to the yards in the first place, or the yard guys sawzall the engine out and the front structures are usually hacked, and they never take the time to pull the harnesses, so they end up cut, and not neatly cut either.

post pics for sure on the progress. i browsed thru mine after posting the other day - brought back some good and bad memories lol. i do have pics of my "tuck". it was good, but the engine bay was so filthy it never really looked that great. and not having wiper washers suuuuuucks.


ms3 - you can probably pick up an intake and you'll probably be good to go. it unlocks a good amount of power and at least makes the car sound good. the exhaust is already well designed for noise and whatnot. my test pipe did free up some power. that's why i am never in a hurry to mod my car, it satisfies me enough.

never cleaned the intake valves. lol. direct injection does make them not get cleaned like in port injection. mine are probably a bit gunky. you could pull the intake manifold, bypass the throttle body coolant while you're there, and throw on some phenolic plastic manifold and throttle body gaskets for heat dissipation. im at 106K now, no issues regarding dirty valves, and i don't have a catch can or anything fancy.

 

Thanks for all the info Dan. I started reconnecting the wiring that will be running back out into the engine bay. So far I'm planning to keep the following wiring coming out the drivers side firewall:
-L/R low beam headlights
-L/R corner lights
-L/R turn signals
-Tripple Pressure Switch
-A/C compressor
-Greddy boost controller solenoid
-prosport water temp sensor
-innovative wideband

Likely removing:
-Brake fluid level sensor
-P/S sensor
-connector to this little silver box on the driver side wheel tub(this piece was never on my car but the connector was just laying there)
-horn wiring
-another unused connector green and pink wires forget what it's for

Questionable:
-my car never had an ambient temp sensor. I never knew about this but isn't this somewhat necessary? From what little I find online it's a parameter that the ECU reads and meters because the factory MAF doesn't have a sensor built in..


I am not planning on redoing the distrib block, fuses, and relays. I'm either going to hack the OE fuse box so that it'll fit in the passenger airbag area OR I'm going to locate all the relays and fuses right near the SMJ and eliminate the max amount of wires. I shouldn't need to service any of it anyway.

The connectors to the engine harness from the fuse box I'm going to run out the passenger side when I tackle that harness but for now I may run them out the drivers side and on top of the bell housing behind the engine and heatwrap them or something.

I plan to go deeper into this with the engine harness too and consolidate everything and move the MAF(and O2 sensor) over to the drivers side for instance so it's not running across or behind the engine.



Im actually shopping for a house currently so this project is going to slow down a bit until I'm moved :/.

 

And about the MS3 I hear mixed things about modding and cleaning the valves too. I kind of don't want to get an intake until I get an AP. I want to have an AP and race pipe and intake to do it all at once, but then I hear the stock HPFP can't keep up even with these small mods and upgraded ones are pricey ... I think I may wait until my warranty is up before dicking with it to be honest.

 

replies in red are so much easier. less scrolling lol.

and yes, i ended up not doing much to my car until the warranty was up at 50K. the intake, bpv, test pipe won't max out the fuel pump. a downpipe will sometimes make people hit fuel cut (bc of boost increases), and a top mount IC upgrade can start to strain the fuel pump. it's such a bitch i don't like taking apart pump internals, and not many of them sell the entire pump anymore, just the upgrade parts. hence why i'm likely done with this car.