View Full Version : Deleting pins and adding pins to engine harness

01-04-2015, 08:30 PM
Trying to tackle down my harness and some concerns i have is leaving some pins out and adding some ect. I am using an sw20 jdm harness and usdm st184 harness to make my conversion for a 3sgte jdm spec.

Deleting these pins on the st184 harness:
-osfc (over speed fuel cut) See my concerns (scroll down)
-NSW (nuetral start switch) See my concerns (scroll down)
-All A/C pins
-OX2 (oxygen sub sensor) See my concerns (scroll down)
-PIM (vacuum sensor) because its something else for the 3sgte.
-VC (Vacuum sensor) because its something else for the 3sgte.

Deleting these pins for the sw20 harness:
-All A/C pins
-CCO (unsure of what this is?)
-EGW (unsure of what this is?)
-THG (egr gas temp. sensor)
-FPR (fuel pump relay) See my concerns (scroll down)
-T-Vis See my concerns (scroll down)
-STJ (cold Start injector) not present on 3sgte jdm ecu

Pins that i think need relocating for the conversion:
-FC (circuit opening relay)
-STA (starter switch)

-STP (stop light switch or 3sgte) is the same for BK on st184 ?
-FC (circuit opening relay) on st184 activates the fuel pump therefore do i need to add FPR (fuel pump relay)?
-VF (check connector) im just rerouting this one
-OSFC (over speed fuel cut) no pin for it on 3sgte ecu is it really needed?
-OX1 (oxygen sensor) can i run my 5sfe oxygen sensor or do i need to run a 3sgte oxygen sensor? i was thinking of leaving the oxygen sensor set up from the 5sfe the same so i can run it with 5sfe oxygen sensor.
-OX2 (oxygen sub sensor) i want to delete this one is it ok? thats because on my Diagram for the 3sgte pins OX2 is check connector.
- CCO and EGW not sure what these pins are for anyone have an idea
-T-VIS my 3sgte has the set up to delete T-Vis but i am not sure what other pin might be involved with it. not sure if it is TPC1(turbochargin preassure vsv) or PIM (turbochargin preassure sensor) because one of those was deleted too
- distributor shield since my sw20 harness was shorter i just cut the plug and transferred to st184 harness i took apart the rubber insulation and undid the shield to ad an aditional wire because it was missing one. my concern is i couldnt rewrap it perfect but i tried my best to do so. will this give any issues ?
-pins related to ISC valve and the following VC, PIM, VS, THA1, IDL, THW, ill inspect this carefully so will do an update on these
-IGT (igniter) plan on using st184 igniter set up should be fine right?
-Injector relay pack not sure if this is suppose to be shielded but for sure insulated. i plan on getting my ground where the 5s injector set up got it from. so basically the injector plugs are suppose to be wired up as the following? positive of the injector plugs to the ecu then the ground to the injector relay pack. then the ground where the 5sfe injectors were grounded to have that wire up to the injector replay pack witch will be only one wire instead of the 4 from the 5sfe injector plugs because the 3sgte injector plugs will have their ground going to the relay pack?

01-06-2015, 03:59 PM
-was told Ignniter has to match my ecu
-injector resistor pack is wired up diff not what i thought it would be. i need to find a wire diagram for this one.

01-08-2015, 02:44 AM

01-14-2015, 03:24 AM
update: Injectors wired up

OX1 needs to have 4 wires right?

01-14-2015, 03:32 AM
btw im basing my wiring of the bgb diagrams. i do have a jdm motor and ecu. i dont think the wire diagram would matter if its jdm right?

01-14-2015, 11:07 AM
I'm assuming that you're using the 2nd gen 3S ECU, correct?

If so, you do need the 3S igniter. If you were using the 3rd gen ECU, you can use a 5S igniter but there are a couple of specific numbers that are recommended.

My 3S O2 sensor has 4 wires. The car is a 92 but it has a replacement JDM engine. My engine harness is set up for the 4 wire sensor so I'm assuming that that the 92-93 had the 4 wire. From my research for the 3rd gen electronics conversion, it looks like some of the earlier 2nd gen gens (90-91?) used a 3 wire O2 sensor. The main difference seems to be the 4 wire is heated.

The wiring diagrams for the USDM engine will work. The main difference between US and JDM is the EGR valve, JDM doesn't have one as you probably already know. Just ignore the pins related to the EGR.

The PIM pin will go to the MAP or turbo pressure sensor on the 3S. If you're using the 2nd gen ECU, the only thing that it does set the fuel cut. The 5S, as far as I know, uses a MAP sensor where the 1st and 2nd gen 3S use the air flow meter. Technically, you can get by without using the MAP on the 2nd gen 3S. I found out early last year that a previous owner had disconnected the vacuum on mine and I had been running the car car for 6 or 7 years without it. I did have a couple of incidents of quick overboost due to the lack of fuel cut.

One thing you do need to do if you haven't already is determine what year ECU you have. You probably already know but the 90-91 and 92-93 are a little different. The engine will run off of either one but you have to make sure that you use the right pinout diagram to wire it up. There are 5 or 6 wires/pins that are in different spots. I had put a 90-91 JDM ECU in my 92 prior to the 3rd gen conversion and had to move a few wires around. Here is a a link to a pretty complete ECU pin diagram.


Hopefully this helps a little. This is all I can think of at the moment as it's early. Find the big wiring diagram that is in the back of the BGB, the one that folds out, and this will help A LOT with the wiring.

01-14-2015, 02:51 PM
I believe mine is a 90-91 ecu for gen2 jdm spec and i got my pin outs from that pic a while back the numbers read 89661-20751. could be a 92 ecu tho im not sure on this one to be exact but i did find the same pin diagram you put

well i actually have like 2 versions of the wire diagram one from the bgb for a 90 alltrac and the other one i got it from one of the 3sgte how to do thread witch has it in color

01-15-2015, 03:13 AM
Based on that number, you've got a 90-91 ECU, the revised one. The 751 number was used March of 90 through August of 91. Be sure to use the 90-91 pin outs when you wire it.

02-03-2015, 10:12 PM
Update: 2/3/15
well i took a small break on my project due to me ending up in the hospital.
i just recently got back to working on it two plugs IG2 (gray) and IG1 (white) are putting me to a halt because i dont have a diagram for them. does anyone knoe were to locate them?

Ive finished doing my injectors and dizzy connectors.
im adding the FPR to the set up and 3sgte 4 wire o2 sensor.

One thing i cant find in the 3sgte wire diagram is the Nuetral start switch. how do i go about this particular switch?

02-05-2015, 11:00 PM
almost done with the harness but i came across the pin HT witch is for the o2 sensor. yet my Ecu 89661-20751 does not have the HT pin from what i see on the ecu pin out diagram. i read in one of the threads from this forum and it said we can bypass the HT. My motor is a jdm spec motor and so is my ecu., from other research i hear that the jdm o2 sensor was a single wire and usdm is 4 wires. that being said can i use my single wire o2 sensor from my 5sfe?

Also being a jdm spec motor ill skip doing the egr components on the harness.

T-Vis was deleted on my motor so do i also not wire up the T-VIS and Turbo vsv's?

basically those are the last things i need to do to finish besides dealing with my grounds and power.

02-06-2015, 12:56 AM
USDM used a 4 wire sensor since at least 90.
JDM didn't use 4 wire 'til 94 [gen III].
You should be able to use your single wire sensor.

Since you gutted your TVIS you won't need to wire it [though it might be nice for future possible use]. Turbo VSV isn't required.
3SGTE didn't have a Neutral Start Switch.

IGI and IGII can be found in the wiring diagram book. You have to dig around the diagrams and piece it together though.

02-07-2015, 05:12 PM
awesome thank, i do plan on wiring up the vsv connectors for future if i ever put it back.

one more thing my T-VIS was deleted diff. i dont have the t-vis and turbo VSV's or the vacuum tanks. i got my 2nd gen jdm spec 3sgte a while back to do my swap. i noticed were the accurator goes is missing and blocked of with two screws. the harness also had the t-vis and turbo VSV's unpinned, im guessing due to no vsv's being present. so my question is how do i delete my T-VIS or has it been taken care of and all i would have to do is block of the hose from the wastegate?

according to a thread on alltrac.net they plug up the wastegate and another component but mine is diff like i just said. those it still work or what is the set up mine has?

also the igniter i was told needs to get changed ived looked up pictures of the igniter and came across the 123 number on the igniter , same as my 5sfe igniter.

02-07-2015, 05:58 PM
Interesting to know about the 3S not having a neutral start switch. I thought mine was bad.

02-08-2015, 03:58 PM
Interesting to know about the 3S not having a neutral start switch. I thought mine was bad.

what is the purpose of having it?

Forgot to mention in my last comment my 3s has the cold start injector so not sure if previous owner ran a newer ecu or just diff cuz his set up was for mr2. do i just remove that plug?

02-10-2015, 04:49 PM

02-12-2015, 01:10 AM
Mike, neutral start switches are for automatics. Manuals use a clutch switch.

Neutral start switch makes sure you can only start if the [automatic] transmission is in park or neutral.

If you want to really "Delete" the TVIS you need to remove all the parts. Including the butterflies in the intake manifold.
But all you have to do to disable it is unplug the actuator. It's normally open, and the actuator closes it. If you disconnect the actuator it will always be open.
But, the consensus is you're better off keeping the TVIS unless you're making a bunch more power than stock.

I'm not sure what you're asking about the cold start injector? All gen II have it. It's ONLY used while the starter runs. As soon as the engine starts it cuts off. Unless you live somewhere really cold you really don't need it.

02-12-2015, 03:48 AM
I've been brain dead lately Jeremy. Clutch switch is what I was thinking about.

Good info about how the cold start injector works. I deleted mine when I did the 3rd gen electronics conversion but always wondered how it functioned.

02-12-2015, 05:36 AM
Hmm thats weird well my ecu didnt seen to have that according to the pin out diagram

02-12-2015, 05:39 AM
But will check again, i knoe were the pin would go to im just not sure why it doesnt have it. My ecu is the one i listed in the previous comments

02-13-2015, 11:52 PM
Which pin? The cold start injector pin?

02-14-2015, 12:41 AM
Yeah but thats basing it of all the other 3sgte pins for the STJ

but im just gonna leave it without it