View Full Version : Chassis harness pinout 90 US vs 92-93 JDM

08-14-2010, 02:45 AM
Selinoid will not engage after putting 92-93 JDM engine, harness, ecu in a 90 US all trac.

So far made sure the pedal is hitting the clutch starter cutoff switch, tested the starter relay ok. Jumped the battery to the starter, starter and selinoid test ok.

Im going to check continuity on the selinoid wire in the engine harness. Incase that is bad. I elongated the harness to reach so testing that is the most logical thing to do first to me.

I looked through the BGB archives and dont think theres any pinouts in those. Wondering if maybe the starter and who knows what else could be on different pins between a 90 US car and 92-93 JDM harness.

Im going to start visually comparing them but couldnt hurt to know what is what is what from a nice simple diagram. Incase other stuff is different too. Where the chassis harness connects to the engine harness. At least should the chassis harness wires be same colors as thier counterparts on the engine harness plug? With my luck probably not.


08-14-2010, 03:09 AM
ChrisD and Tweak are likely going to be your best resources for swap wiring info, if you don't get a quick reply, try PMing them.

It's still solenoid. Built-in spell-checkers FTW.

The Captain
08-14-2010, 04:30 AM
Should be the same for the years. Only difference is the EGR system. I have a 90 JDM in my 90 US car. Plugged right in. I'm sure the 92-93 pins are the same as US models. Others will know for sure.

08-14-2010, 05:49 AM
Yeah I was having fun with the spelling. Nothing inside the car has changed and it was all working when I started so its got to be something simple. Like the modified harness. So if chassis wire pins are the same then its got to be the harness. Testing starts tommorrow!

08-14-2010, 02:36 PM
+1 to what the Captain said. My car's a 92 and I have a 90-91 JDM ECU. I did have repin the ECU side of harness but that was only because of the model year difference. Everything else worked fine.

You might be on to something on wire between the starter relay and the solenoid. If you've got power to the relay and it's working then it's almost got to be in the wiring from there to the starter or the starter itself. I went through something like this a couple of years ago except I had no power at all in the car. In my case it was a shorted starter. In your case it really sounds like it might be in the wiring to the starter.

08-15-2010, 06:31 AM
I took the engine harness apart and tested every single extension and I felt vindicated when all was good. Except the turbo pressure indicator had pulled apart but that doesnt explain my starter power problem. The soleniod wire is black at the starter but couldnt find that at the relay junction box or on the harness at all. So wasnt able to totally test that. So Ill have to start testing the wires to the ignition and whatnot next. Bummer. One thing did change. The check engine light blinks rapidly instead of staying solid when the key is on. But since its not running yet that doesnt help.

08-15-2010, 03:09 PM
I've got the 92 wiring diagram book but I don't have a scanner here.

Anyway, according to the diagram for the 92, the starter wire black all the way back to the relay. It comes off of pin #4 on the relay. From there it shows going into the harness at a connector back in the passenger side corner of the engine compartment.

Not much but hopefully it might help. If everything else has checked out it's almost has to be something in that wire. From the diagram, the only other thing in the circuit is the start injector time switch and the cold start injector but that comes off a connector in the harness and is not in a direct line to between the starter and the relay though.

08-16-2010, 06:05 PM
90 US All Trac with 92-93 JDM engine, trans, harness, ECU.

Starter soleniod is not getting power when I turn the key and it worked before the swap so wondering if theres something different between the chassis harness between models. Since everything worked before the swap its the only thing that makes sense. Everyone says they should be the same. But I havent been able to find a diagram of the chassis pins where it connects to the engine harness.

According to this the chassis to ECU shows that JDM has CCO and and US does not, any idea what CCO is? http://gt4.mwp.id.au/Electrical/All%203SGTE%20ECU%20Diagram.png

So right now my questions are what is CCO and does a diagram exist of the 90 all trac chassis pins?


08-16-2010, 06:46 PM
That relay must go through the chassis wiring because the engine harness goes straight to the ECU and 2 chassis plugs, one other little plug to a unit behind the glove box. The relay is on a panel under the kick panel and the wires go up and must go across top of dash and back down somewhere else. But I know for sure the relay doesnt go directly to the engine harness.

08-16-2010, 06:53 PM
90-91 and 92-93 pinouts are different. That is where your issue is.

CCO stands for "Check Connector Outputs". You do not need this installed.

08-16-2010, 07:55 PM
So do I just need to re arrange the pins to match my 90 harness or are there different colors to worry about?

I wont find out till I get home and the suspense will be killing me eh!


08-16-2010, 11:04 PM
Yeah, just repin them. I wouldn't rely on wire colours. Just reference the pinout diagrams for each, and move around the different ones. It's a bit of a pain because the pins on the outer edges of the plugs are a larger size than the pins on the inside of the plug, so you might have to cut/solder a couple. But all in all, maybe a 2 hour job or so (if you're slow like me).

08-16-2010, 11:30 PM
The wiring diagram shows it coming into the engine bay in the passenger side corner. The plug in the diagram looks like it should be somewhere around where the AC lines go into the firewall. The wire should be black.

08-17-2010, 04:44 AM
Again, this is all about the chassis plugs, not the ECU plugs. The engine harness that goes in the hole on top corner of firewall contains only one solid black I believe and that was for the distributor 4 wrapped together, so Im thinking the soleniod changes color somewhere. But anyway, the engine wiring harness has 2 plugs that go to the ECU, my ECU and harness are both 92-93 JDM from the same donor car. So no problem there. The differences are the 2 plugs from the chassis. Actually 3 now that I think it. 3 plugs come from the chassis harness inside the car. 1 plug goes to ECU, 2 plugs connect to the Engine harness. I just got done diagramming the colors on 2, realize I have to go back and check the 3rd that goes to the ECU for differences. This will probably take me a week or more. Ive still seen no diagrams saying which chassis wires are for what. Still have to check ChrisD's site. I agree some of the colors are hard to identify. Or probaly are different colored wires for the same thing so safety requires a diagram. If I can find one. Its the first time Ive had to do this so that makes it triple hard. I am glad that I know where the problem is and just have to tackle it.

08-17-2010, 04:12 PM
My JDM chassis wire colors match the diagram on ChrisD's site, you must have a JDM car? I still need to figure out what is what on my USDM so I know what to relocate to where on the plug. Your st185 chassis pinout is the only one Ive seen so far.

08-17-2010, 06:50 PM
Not sure what I was reading before, but yeah ignore my comment on repinning the ECU.

Do you have this plug connected properly? It should sit in the corner right beside where the wiring harness goes through the firewall.


08-17-2010, 10:09 PM
If you mean pass side, not really. There are the 3 plugs, one goes on the AC line, dont know what exactly other 2 are, that I had to elongate to reach across the engine bay to by where the harness hole is. But none of them are cylindrical like that. The closest I have to that is the well, 2 big cylinder ones I can think of is the one on the little finned box that mounts by the batt and radiator fan and the other is the cruise control plug.

Why do you ask?

And also, are you saying not to worry about re pinning the chassis to ecu plug? But I must still have to re pin the 2 (white and gray) chassis to engine harness plugs.

When I get home, if I want some help, I should take a bunch of pics and post them on cardomain so I can post them here. Hopefully that will help.

08-18-2010, 12:24 AM
Ok here we go, this will probably just cause more questions. Its nothing you dont know what it is so maybe will just help to visualize. I still dont know how Im going to re pin the chassis connections unless I know what the wires do. But you said you were thinking of something else, (ChrisD) when you said that so dont know if , well no, the wires are different cause I compared them. So I can try and make them the same but then couple other ones get displaced. So I posted a diagram on here too. Still have to add the chassis to ECU plug comparison. And the colors go by wirecolor\lengthwise stripe\crosswise stripe , yeah I know Im not up on the terms yet. http://www.cardomain.com/ride/3868879/2

08-18-2010, 01:17 AM
OK, I never said the wire between the solenoid and the starter relay was in the engine harness. It's part of the body harness. If you can't trace it back from the solenoid to the relay try going the other way. If your starter works with you jump it over, it pretty much has to be something with that wire. Unless you changed the body harness out, the wire will be black from the relay to the solenoid. It will come into the entering the engine compartment on the right side near the AC connections. See if you can find that and check it.

08-18-2010, 03:19 PM
Well it does go into the engine harness but I spose it could come back out through the relay box and go around the radiator support and fender wall and back to the relay inside the car. Since the relay box in engine bay doesnt list any starter stuff, didnt think so, but since the wire from the relay box goes towards the fender area I spose thats possible.

08-19-2010, 01:22 AM
So what are my possiblilities locally then? Maybe an auto electrician or something. Im really stuck without some help with this. According to a diagram I found here are the differences between my old setup and my new setup. I just need to know where to move the pins to, which ones to leave out, etc.


08-19-2010, 01:55 AM
Well it does go into the engine harness but I spose it could come back out through the relay box and go around the radiator support and fender wall and back to the relay inside the car. Since the relay box in engine bay doesnt list any starter stuff, didnt think so, but since the wire from the relay box goes towards the fender area I spose thats possible.

It's possible. That's how it works. Try tracing it out.

08-19-2010, 09:06 PM
Would some of my re-pinning woes be alleviated by finding a JDM AFM?

08-20-2010, 04:13 AM
I don't think so. I've got a JDM engine in my car and I installed a JDM ECU a couple of years ago with no issues other repinning the necessary items to make it the 90-91 ECU work with the 92-93 harness.

Your engine harness is the same model year as the ECU isn't it? You shouldn't have to repin anything. The ECU's, if they are the same year as the harness, is plug and play.

Other than the RC AFM, there's not any difference between the JDM and the USDM. The only difference in the engines is the lack of the EGR valve on the JDM engine.

08-20-2010, 06:00 AM
Yes my engine, harness, ECU are all the same. JDM 92. Its all from same JDM donor car. That makes sense, ofcourse it should work, but then I got into this that the chassis pins are all switched around. Or so I was told. No one seems to know for sure and ther are no pinout diagrams for them anywhere.

08-20-2010, 06:03 PM
That is because Toyota didn't create diagrams by connector with pinouts for each one. The only pinout diagram that exists is at the ECU. Everything else is in the EWD books by system circuit.

If you mean pass side, not really. There are the 3 plugs, one goes on the AC line, dont know what exactly other 2 are, that I had to elongate to reach across the engine bay to by where the harness hole is. But none of them are cylindrical like that. The closest I have to that is the well, 2 big cylinder ones I can think of is the one on the little finned box that mounts by the batt and radiator fan and the other is the cruise control plug.

There should be a big cylindrical plug, with 3 wires on it. It is on the passenger side of both JDM and USDM cars. So that means, on JDM it is on the left hand side, USDM it is on the right hand side. Should be close to the boot for the firewall pass-through.

This plug is key! This is basically the power wire to your ignition switch, which in turn powers your starter. Lets find this before testing the starter circuit....

08-20-2010, 08:36 PM
I will look but I think I would remember that plug and I dont. Im pretty sure there is no such plug near the firewall on either side. Before or after the swap, and it ran with the old engine. The only plug that looks anything like your picture is the one i have up front by the battery. Same looking , has 3 wires, I will check to be sure when I get home but heres a pic http://carphotos.cardomain.com/ride_images/4/476/2589/38688794003_medium.jpg to see it bigger, and the rest of my engine bay look here http://www.cardomain.com/ride/3868879/2 I'll post again in couple hours with the visual confirmation.

---------- Post added at 02:36 PM ---------- Previous post was at 01:02 PM ----------

Ok, I found it, its there just not cylindrical. I never new that plug was for starter power so that was a big missing piece. Good call ChrisD. Tested fine between the solenoid wire at starter, the positive battery wire and the plug, dont know where that white wire starts. Then I tested between where the relay plugs in under the kick panel and the plug by the boot hole. One wire tested ok and other 2 got no reading. So there something going on there. Ill have to figure that out. And then try to start it again. And then its on to the next thing. Thanks!

08-21-2010, 07:04 AM
Hey one other thought. Does it require a loop through the cruise control for the engine to fire?

08-21-2010, 11:53 PM
Ok the plug to the starter relay is fine, only one of those 3 wires in the plug even go to it. Thats why it didnt seem to be testing ok. The other 2 wires go somewhere else. And they arent even on the diagram in my chiltons. So that plug pictured by ChrisD only has 1 wire in it that goes from starter solenoid to the starter relay. Got any other ideas what to check next? I still think theres gotta be something easy that allowed my US setup to work and the JDM to not. The search continues.
What are the wires on the drivers side kick panel for?

Heres an even bigger question. Does the starter require the ECU to be plugged in, and also the 2 chassis plugs. I think that would narrow it down to the chassis plugs.

08-23-2010, 02:01 AM
I thought of something today. Have you checked the clutch switch to make sure that it is working. On my car sometimes if I don't get the pedal against the floor the solenoid will click but the starter won't do anything. It doesn't do it all the time but on occasions it happens. It's possible the switch could be bad. That would keep it from starting with everything else being good. Just an idea.

08-23-2010, 03:56 PM
I checked to make sure that the button was getting pushed in. But its so hard to get too not sure how to test it.

08-23-2010, 11:16 PM
What you'll probably need to do is pull it out and check it with a meter to see if its working. It might not be the problem but it's worth checking before you tear into the harnesses.

08-24-2010, 05:20 PM
Ok if you are sure the plug I described is dealt with, then it is time to check continuity and voltages in the starter circuit. Check the BGB for the starter system circuit, and start running through. Use the Toyota book, not Chiltons. If you don't have it we have it hosted here on the BGB online section.

08-25-2010, 04:16 AM
Ill keep checking the starter stuff in the car but I think its way more likely the problem lies with the differences with the pinning of my 90 car and the 92-93 JDM engine/harness/ecu that I installed. All the starter stuff worked fine when I drove it into the garage and none of it has been touched. Believe me if I ever figure that out it will be documented for the next guy that attempts it.

09-03-2010, 01:15 AM
I just got the clutch starter switch out and tested ok.

09-03-2010, 02:06 AM
Well so much for that idea.

Have you tried having someone hit the key while you check and see if you've got power to the wire coming from the starter relay to the solenoid? I'm still wondering about that. If the relay is clicking when you hit the key, you've got power in the ignition circuit up to that point. There could still be something wrong with that wire that's not obvious.

09-03-2010, 02:12 AM
Thats a good idea but it doesnt click at all, which I guess means no power in the wire. We did jump the batt straight to the starter and the selonoid so I know they do work. Theres got to be something inbetween my new JDM engine/harness/ecu and my US car thats blocking it. Thats got to be it but what exactly is the mystery.

Does anyone know if the cruise control has to be plugged in for the starter to go? Or for the engine to run? It worked without the cruise in my US setup so maybe not. But the cruise unit plug does have red, blue and yellow wires just like the distributor wires in the engine harness.

How about this, the clutch starter switch wires are white black and silver, and black silver stripe. And the chassis to ECU plug has a black silver strip wire! And according to the ECU pinout that wire has to do with the starter but for JDM and US looks like they are on the same pin. Ugh. Dont know if that means anything or not.

09-03-2010, 05:29 PM
To answer your questions above:

-No, cruise control is not part of the circuit in any way.
-Forget the chassis to ECU plug for right now...that may be the STA pin to the circuit opening relay...but we'd have to look at that at another time. What I write below will solve our issue.

Ok...so I'm going to walk through all the items that could possibly have anything to do with the starter. For now, forget about any of the other possibilities and just try these one by one. We *will* find the problem with these steps.

To begin, here is the starting and ignition page from the Toyota EWD:

http://www.celicatech.com/gallery/files/4/img_0771_thumb.jpg (http://www.celicatech.com/gallery/showimage.php?i=17100&c=41)

You have a multi-meter right?

Test Clutch Start Switch

Ok, this is actually easier to test than you'd think.

1. Find your starter relay.
2. Test continuity between pin 3 on the starter relay, and a good ground point on the car. Test with the clutch fully depressed.
3. Test without.
4. You should see continuity between pin 3 and ground with the clutch depressed, and nothing when the clutch is not pressed. If not as described, your issue is here.

Test power to starter

So we're now going to test the circuit the full length, then start narrowing down.

Test from battery to starter

1. **Important** Disconnect the positive terminal of the battery.
2. Check continuity from the positive battery wire with the battery disconnected to the thinner wire on the starter, with the key held in the "start" position. Someone will have to manually hold the key in this position while you test.

This should fail, otherwise your car would start. Proceed to next step. Connect your battery again.

Eliminate the fusible link box (small box right beside the fuse box)

1. Check all fusible links for any that may have failed
2. Test continuity between the white wire on the fusible link box (terminal 2) and the thin wire on the starter (black), with the key turned to the "start" position. Someone will have to manually hold the key in this position while you test.
3. If passes, your problem is with the fusible link box connections, or the connection from the battery to this box.
4. If fails, proceed to next.

Eliminate the fuse box

Refer to the following diagram for the next test.

http://www.celicatech.com/gallery/files/4/img_0769_thumb.jpg (http://www.celicatech.com/gallery/showimage.php?i=17099&c=41)

1. Test continuity between plug 2E terminal 5 (white wire) and the thin wire on the starter (black), with the key turned to the "start" position. Someone will have to manually hold the key in this position while you test.
3. If passes, your problem is with the fuse box connections, or the connection from the fusible link box to this fuse box.
4. If fails, proceed to next.

Eliminate plug IE1 and the Ignition Switch as problems

1. Test continuity between fuse box plug 2E terminal 5 (white wire) and terminal 2 on the starter relay (black/white). (there are 2 black/white wires, either will work the same for this test), with the key turned to the "start" position. Someone will have to manually hold the key in this position while you test.
2. If passes, plugs IE1 and the Ignition Switch are fine.
3. If fails, Your issue is with either IE1, the ignition switch, or the wiring in between. IE1 is in the drivers side kick panel and is a pain to get at. But since you haven't touched those, I see no reason for them to have failed.

Eliminate the starter relay as the problem

1. Test continuity between pins 2 (black/white) and 4 (black) on the starter relay, with the key turned to the "start" position. Someone will have to manually hold the key in this position while you test.
2. If passes, your starter relay is fine.
3. If fails, replace the starter relay.

Eliminate plug EB1 and wiring from relay to starter

1. From starter relay, test continuity from pin 4 (black) to the thin wire at the starter.
2. If passes, then your circuit is proven complete. If you are still reading at this point then it shouldn't pass.
3. If fails, then the issue is with the wiring between the starter relay and the starter itself. Most likely, it is with plug EB1 (uses pin 2). This is the plug I referred to previously, and should be near the pass-through on the firewall. It should also have a white and a black/orange wire. From there I would test either side of that plug with continuity to the starter relay, and from the plug to the starter itself, to find out which side the issue is on.

OK. So that sums it up. If you follow these steps you will have tested the complete starter circuit, and you WILL find where your problem is.

Good luck!

09-03-2010, 07:06 PM
When I test it, does the engine harness have to be plugged in for the starter to crank?


09-04-2010, 03:47 AM
I don't think you'd have to have engine harness hooked up. The starter circuit is inside the car and in the wire going to the solenoid. Check the stuff that Chris put up and that should give you a pretty good idea of what makes up the circuit.

09-04-2010, 07:33 AM
I tested everything twice and posted whats below but editing this post, I MAY have just figured out the whole problem, between my US harness and the JDM engine harness, on the fusible links plug the wires are different colors, doesnt even have a white wire on pin 2, has black wire. And on the plug at the firewall the black solenoid wire goes in differnt pin, pics at the bottom. So I'll probly have to repin those to match. Not sure what to do about the fusible links plug because doesnt even have a white wire. Please reply and let me know what you think. Cripes!

OK, heres part one of the results, part 2 late tomorrow. With the battery disconnected completely and the engine harness not plugged in, which shouldnt matter. I also came up with a testing trick for the hard core. If you go more that one tester, just link an extra terminal wire together and you dont need someone to turn the key for you. Reaches from engine bay to inside the car and turn the key yourself!

Im guessing these are passes because of ground and distance but let me know.

Clutch start switch, .00 with key to start.

Batt to starter, key to ON .11, key to start .03

Reconnected battery, Also Im guessing the "fusible link box" is that metal deal with fins next to the batt with the big round plug on it? key to ON .08, key to start -1, (no idea what that means)

The fuse box or relay box got, 1 fail, but it passed yesterday wo battery connected.

IE1 and ignition switch got, key to start -3.25 (no idea what this means)

starter relay got no reading, 1, should I have the realy plugged in and test the back of the panel?

and EB1 to starter relay, nothing, 1. But heres something strange. That black wire from starter solenoid doesnt go all the way through to the relay! and it looks factory. The plug by the firewall has 4 pins but only 3 are used. The black solenoid wire goes to the empty pin on the plug!! Doesnt make any sense so I took pics. The black wire goes in the bottom pin, other side of the plug the continuing pin is on top!

09-07-2010, 05:30 PM
Haha well there ya go. That is odd they moved the pin placement.

I will post up info on your third ECU plug in a bit.

09-07-2010, 05:30 PM
Haha well there ya go. That is odd they moved the pin placement.

I will post up info on your third ECU plug in a bit.

09-08-2010, 01:49 AM
Going to an empty socket would probably do it!

09-09-2010, 07:10 PM
OK, taken a quick look at the 3rd ECU plug. Looking at your diagrams posted above, there is really only 1 wire to deal with: FC.

I have also verified with this really good master pinout sheet:

http://www.celicatech.com/gallery/files/4/all_3sgte_ecu_diagram_thumb.png (http://www.celicatech.com/gallery/showimage.php?i=17125&c=41)

FC is pretty easy to deal with actually.

So you will need to ADD a wire on the 3rd plug, where FC is on the 1993 ECU. This wire is to go directly to pin 4 (bottom row, middle) on the Circuit Opening Relay, which is the small relay that mounts to the side of the ECU. This wire is green, if you happen to have the old harness and want to be consistent.

And that's it!

I would check over the wiring to the Circuit Opening Relay just in case any of the others don't go where they should, but I think you will be ok.

09-09-2010, 08:09 PM
On that chart, the third one down is a different part number from the one I have. My JDM ECU is the -2B280 that is further down and the FC is on pin 3 not pin 4 is that correct? And my 90 US ECU is -20761 and it does have an FC.

Ok so the pin3 vs pin4 confusion, all I have to do is move the green FC wire from the big plug to the medium plug on bottom row, 3rd from the right. ?
To make this I used the same pinout diagram, to illustrate my point I just put the 2 together so easier to see.


Thanks, replies not withstanding Im going to race home after work and it will be the first thing I do.

09-09-2010, 09:40 PM
On that chart, the third one down is a different part number from the one I have. My JDM ECU is the -2B280 that is further down and the FC is on pin 3 not pin 4 is that correct? And my 90 US ECU is -20761 and it does have an FC.

The 3rd one down is the JDM 90-91 ECU. The 7th one down is the JDM 92-93. In any case, they do correspond with your chart there, so use that and you'll be fine.

Ok so the pin3 vs pin4 confusion, all I have to do is move the green FC wire from the big plug to the medium plug on bottom row, 3rd from the right. ?

Sorta. You can't "move it", because, on your JDM harness, it's not there. ;) Instead your JDM harness has the G- wire there.

Basically you just need a new wire, a new pin, and add it in on the bottom row, third from the right, and wire it straight to the COR. :)

Thanks, replies not withstanding Im going to race home after work and it will be the first thing I do.

Good luck!

09-09-2010, 09:56 PM
But it is there. I do have the 93 JDM ECU and harness. Its on both the 90 US and the 93 JDM but in different places.

So I should be able to just move it, not add it. ? If not i will really be confused, again.

09-09-2010, 10:10 PM
Yes, but, on the JDM ECU FC is on the 3rd plug, while on the USDM ECU FC is on the 1st plug.

The 3rd plug is different because it comes from the interior, not from the engine harness. So since your previous ECU had FC coming from the engine harness, and since you've switched to the JDM harness where it should now come from the interior, FC is no longer wired in.

Hope that makes sense?

In any case, just verify that FC is indeed wired from the COR to the ECU on the 3rd plug, and you'll be golden.

09-09-2010, 10:29 PM
Ok I think I get it now. See what happens. I only recently found my COR hanging loose under the carpet, didnt know what it was until today. Thanks a bunch!

09-10-2010, 01:10 AM
Ok, well I got the FC moved. The starter cranks but the engine wont fire. The only thing that doesnt jive is that when you say that pin 4 on the COR is green. Mine isnt. But pin 2 is green w red stripe. Its like my pin 2 and 4 are reversed, but the green wire did go to pin 22 on the grey plug like the diagram on your swap site. Which is labeled as "description coming soon". Which then goes to the bottom 4th from right pin on big ecu plug which is FC on US and on to the FC on the US big ecu plug, G- on JDM. So thats the one I moved, COR pin 2, I figured maybe they were reversed like my starter relay plug pin was reversed for no reason. So maybe either the colors or the pin numbers are mixed up? I could try running my yellow and black wire on the COR pin 4 but thought Id ask first instead of hacking my chassis harness up too much. I spose I should just go ahead and do that. Your COR shows solid lite green and not dark green and red like mine. So maybe my yellow and black pin 4 IS the right one to move? Thoughts?



09-10-2010, 05:31 AM
I seem to recall that some of the COR's are different, but I'd have to see it to be sure. I was referencing a 1990 diagram, and my site is also based on the 1990 model. So the 93's might be different.

Is there a diagram on the side of the relay? Compare it to this diagram on page 3 / page 56: http://www.celicatech.com/imagearchive/bgbonline/90ewd/AT/ATengcntrl.pdf

The position of the black/yellow and FC wires are critical, as the black yellow supplies power to the fuel pump essentially, and the FC activates the relay allowing black/yellow to flow to blue/orange.

But the wiring for FC is really straight forward. Just needs a wire straight from the COR to the 3rd ECU plug, bottom row, 3rd from the right. Do not remove G- no matter what. It is on the 1st plug for the JDM '93, and should be coming straight from your engine harness. So no need to touch it.

So basically I'd just make sure the COR is wired like the diagram on the side says, according to the diagram I have just linked to.

BTW - yeah I think FC is dark green usually. The red stripe is irrelevant usually. Toyota mostly uses a red stripe or two to designate that it branches off from another wire of the same colour. But sometimes it's there for no reason.

09-10-2010, 04:33 PM
Man that is weird! According to that diagram, no matter what color it is, pin 4 on the COR is the right one. But for some reason, my pin 4 is yellow and black and pin 2 is green. Madness. I guess I will try routing the pin 4 yellow and black then and put the pin 2 back where it was.

09-10-2010, 04:38 PM
I wouldn't mess with the colours. More than likely they are right. Black / yellow is + 12V on ignition, FC is a circuit open signal. Check the diagram on the relay.

It is very important. :)

09-10-2010, 05:26 PM
And just to be sure, do you mean to splice the FC to the current wire? When you say add a wire. So it would be like a Y. 2 wires going to the pin 4 on the COR? Because the way I read it I thought I was taking that wire and putting it on another pin on the other ECU plug.


09-10-2010, 07:03 PM
Oh yeah, since the green wire right now goes into the interior harness through that IG1 or IG2 plug, it probably doesn't actually terminate anywhere. If it was like that I would cut it, and route it directly to the 3rd ECU plug, bottom row, 3rd from the right. (it does not need to go anywhere else)

I know, hard to explain these things without being able to see them! :) :)

09-11-2010, 02:03 AM
Ok I put the COR pin 4 to the ECU medium plug bottom pin 3. Still wont fire. Im totally not sure but I cant hear the fuel pump come on. I tested the COR pins and the switch seems to be correct to the diagram and the resistors seem to be correct to the diagram. So my COR wire colors are wrong, but the purpose of those pin locations seem to be true to the diagram. The green wire I moved yesterday goes to gray plug pin 25 on your swap site diagram, no description for it, I think it went to the G- on the ECU, hope that didnt fry it. But its hooked back up. And the COR pin 4 is going where instructed. The pin 4 wire goes to the grey plug pin 25 on your swap site with no description. So, whats next? I figured I will test the switch in the COR to see if it opens when the key is turned. Other than that Im at a standstill again. So I took some pics hoping it would help. Also there is no diagram on my COR unit. EDIT: I tested all my splices are OK, and tried to test the fuel pump switch function. I hooked up the battery. Everything is plugged in.

with the tester on pin 1 and pin 2 of the COR, key to off is at 0.00, key ot acc is at -0.00, key to on is at .63. didnt try turning key to start since fuel pump should come on with key to on. Does this tell us anything? Thanks.

big sized pics are here http://www.cardomain.com/ride/3868879


09-12-2010, 12:45 AM
i had the same issue... your fc wire turns on your fuel pump so your not getting any fuel. hook up the green wire from the interior to the fc location for the JDM harness and it should work.

09-12-2010, 01:36 AM
I already did that. I was told the that pin 4 on the circuit open relay should go to the FC location. The diagram says its green but mine is yellow black, and the wire that should be yellow black, is green. I tried running them both to the FC location on the chassis to ecu plug. Neither worked. Its in the pictures above. I really think that my pump is not coming on. But dont know why. I wired it like you and ChrisD said and its not coming on. Its very confusing.

I noticed just now in my pic that the CCO wire should on that bottom row to. And according to that pinout diagram that ACT wire shouldnt even be on a US plug but mine has it. Any idea what CCO is and where it comes from if its needed?

09-12-2010, 11:51 AM
jump fc and b1 in your diagnostic panel see if it starts.

09-12-2010, 05:39 PM
Does that mean run a wire from the FC wire on the ECU plug all the way to the Diagnostic panel in the engine bay? If so theres no B1 in the diagnostic panel. Sorry but Im new enough to this application to need lots of detail when it comes to this stuff.
Diagnostic panel in engine bay:

09-13-2010, 12:00 AM
FP to +B inside the diagnostic and see if it starts

09-13-2010, 01:18 AM
Jumped FP to +B on the diagnostic panel. No start and still cant hear the pump come on. What does that tell us? Its supposed to have a new fuel pump, within 3 years, and it worked in may but has been sitting all summer while doing the engine swap.

09-13-2010, 06:13 PM
Would the ECU stop the FP from working if it was fried?

09-13-2010, 08:08 PM
Would the ECU stop the FP from working if it was fried?


One way to test if you fuel pump is working is to remove the return hose going into the return pipe, and run that down into a bucket. Bridge +B and FP while doing this (battery power straight to the fuel pump). If it's working, fuel should pour into it.

Be very careful while doing this...you don't want this spraying all over the place.

09-13-2010, 08:13 PM
Ill try that. but heres another question. From my tester readings, is it possible its not grounding properly? Does G1 have anything to do with it and how can I test it?


09-13-2010, 08:16 PM
Oh yes - CCO - not required, ignore it. CCO stands for "Check Connector Outputs". You do not need it. What it does is a bit complex but has absolutely no bearing on getting the car started or how it runs.

---------- Post added at 01:16 PM ---------- Previous post was at 01:14 PM ----------

G1 is a distributor wire. It is possible that there are grounding issues, but wiring in the pump is pretty straight forward.

09-13-2010, 09:24 PM
I meant to say G-. But so I guess I dont know what to do next. The problem has got to be in the wiring. I cut that pin 4 COR and put it to the RC. So what else could keep the switch from grounding? Or If pump doenst run when jumping it on the diag panel how do I run that down?

09-14-2010, 04:49 PM
G- is also distributor.

Does the COR have a diagram on the side of it?

Make sure it is wired according to the diagram, by referencing this: http://www.celicatech.com/imagearchive/bgbonline/90ewd/AT/ATengcntrl.pdf

There is only one place there could be an issue if bridging the FP pin in the diagnostics box with battery, which is at the IG2 plug. If you look there and make sure that the blue/black wire is going to the blue / black wire, it is hooked up.

So what I would do:

1. Check and verify COR wiring
2. Test fuel pump for operation

09-14-2010, 05:52 PM
Theres no diag on the COR, I posted pics of it above. Its just a little relay box with a plug in it.

09-14-2010, 06:44 PM
One easier way to rule in/out the COR as the issue is to remove it from the equation for testing.

Bridge the black/yellow wire and the blue/orange wire. That just sends ignition switched power to the pump directly. But then again, you've already tried to jump Battery power to the pump with no success, so maybe not. Double check your IG1 and IG2 plugs to make sure that the fuel pump wires line up.

Also, make sure you've got spark while you're at it.

I wish I were there to help ya, I'm sure I could get it running inside of an hour. We'll keep trying till we get it!

09-14-2010, 08:55 PM
Are you sure that the FC wire is the only one thats needed to change? That G1, G2 looks like it would matter if its distributor?

09-14-2010, 09:07 PM
But they are on the 1st ECU plug. This plug comes from the engine harness. Since you are using the JDM engine harness and JDM ECU, there's nothing to change. The 3rd plug is important because it comes from the chassis harness, and in your USDM car is wired for the USDM ECU. So you need to make it wired like the JDM would be. Luckily, the only difference that matters on the 3rd plug is FC, so it's relatively straight forward.

09-14-2010, 09:40 PM
Oops, i was looking at the wrong plug.

09-15-2010, 02:23 AM
Theres something strange going on. On engine control diag, the COR pin 2 goes to B+ but mine doesnt. It goes to the big grey chassis plug (pin 22 undefined on ChrisD site) and then goes into the big ECU plug to where G- is supposed to be. And also where G2 is supposed to be on the big ECU plug there is nothing. Are you sure that engine control diag is for JDM? Is there a US version from the same source that I could compare it to? And who knows if that ECU pinout we used is even correct?

09-15-2010, 08:38 PM
Engine control is done the same way no matter JDM/USDM. That diagram is USDM. I've never used a JDM one, or seen one (185 anyway) that I can remember. And I've done far more complex swaps than this.

For ECU pinouts. Pop open the ECU cover plate, all the pinouts are listed there. Run through them and make sure they are what the '93 should be.

Like you mentioned in PM - sure, take some pics of the ECU plugs and I can take a look at them...or draw them out in MS Paint or something.

COR pin 2 - is yours black/yellow? That is very strange, since nothing, absolutely nothing, should go to G-. All the distributor wires are shielded in the same bundle, and are closed off after 6 inches or so.

Something odd is definitely happening though. Did you test your fuel pump?

09-15-2010, 09:27 PM
Thanks, Ill do all that tonight hopefully. Didnt have much time last night.

09-16-2010, 03:47 AM
Ok, I got some pretty crazy stuff to tell. I tried the fuel pump by jumping the switch pins in the COR. I still didnt hear it come on, but I pulled the return hose off and there was gas in it but no pressure.

Then I checked for spark by spraying a bunch of starting fluid into the intake tube in front of the turbo. I got nothing but some smoke vapor from the fluid, dont know where the heat came from to burn it in the tube. But no engine firing meaning no spark.

I checked the pin IDs inside my JDM ECU and they match up to the JDM diagram with some fill in the blank spaces but otherwise matching. So its definitely JDM. BUT when I started checking the wires on the ECU plugs, the distributor wires seem to be in the US positions. The small plug has empty holes where the US one should have empty holes, same with the medium plug. Donít have diagrams for these plugs so cant check colors against what they should be for.

Now, why this is so perplexing is that I ordered a complete JDM setup from one of those resellers on the coast that ship them from japan in containers. My engine has the JDM starter and the JDM alternator air cover intake deal and the DriveJoy JDM oil filter that looks like a robot inside, also has the non EGR intake. And it definately came with a JDM ECU. The harness was also supposed to be JDM but seems to be wired for US ECU?

So I dont know why it would get rewired or reharnessed and shipped with a JDM ECU. Those resellers just put them on racks and take them down and ship them. As far as I know. Im sure they do as little labor as possible and they carry all makes and models so they are not gonna go through and rewire all the harnesses and then bother to ship the JDM ECUs with the Engines. Plus when I repined I couldnít help but break the plug pin locks, so if the harness was repined Id say only the Japanese could do it without breaking the pin locks.

So its possible the gas was in the line from when I first tried it, or after I repinned the FC with JDM ECU. Ill check that and try my old US ECU tomorrow I guess. But I hope ChrisD can look at these pics and confirm what I suspect. Or not. It still would not explain why my COR would have powered the fuel pump with the JDM ECU before I repined it.

Now, the wiring. If you look at these pics and compare with the ECU pinout we used. And compare with the Engine control diagram, I couldnt tell for sure because on the diagram I dont know if NE and G- are the same thing between US and JDM distributors and also the diagram colors are R is Red, Y is Yellow, B is Brown and IF L is Light Blue then they do match up.

Anyway, my brain hurts now but hopefully it means I can get this B started this weekend. Thanks

Please look here for large pic versions. If I post here they are way to big.

There was a label on the engine harness with a number on it but google didnt find it. Any idea where I could search?


09-16-2010, 04:51 PM
JDM vs USDM means very little with the wiring harness. What is more important is 90-91, and 92-93.

However, it definitely looks like you have a harness for 90-91. Are you 100% certain you have a 92-93 engine? How many studs do you have on your exhaust manifold?

So, since I was assuming that you had the 92-93 engine being fitted into a 90-91 car, that changes things quite a bit. That is why we got confused with the whole FC discussion.

What I think you mean then is that you have a 92-93 ECU. (JDM or USDM, doesn't matter they are pinned the same for those years aside from a few JDM specific exceptions)

So you could either use your original 90-91 USDM ECU, and it should plug in just fine, or you can repin for the 92-93 ECU. And if it is JDM, you'd benefit from the more aggressive timing maps.

But yeah, definitely, definitely your car won't start if the harness and ECU are different years! My guess with the importing company is that they shipped you a 90-91 engine, and just grabbed an ECU from a pile which happened to be 92-93.

Just make really really sure that you have the 92-93 ECU before you go ahead! (but it sounds like you do)

Luckily you can repin them, just takes a bit of time. So basically you need to make your harness wired to how the 92-93 harness would be.

My advice: print off both ECU pinout diagrams. Then use them as a checklist. Mark an X through each pin as you move them over, or if they are already in the right spot. Then you can keep track at all times.

---------- Post added at 09:51 AM ---------- Previous post was at 09:50 AM ----------

Also, I am moving this to the Forced Induction forum. 3SGTE specific and swap info is generally discussed there. Hopefully more people will see this discussion in that forum.

09-16-2010, 08:16 PM
That makes sense. My bottom of exhaust manifold where it bolts to the front pipe has 3 studs so Im guessing the engine is 91. what a bummer. but still good news.

Ok so do you mean my 90 US ECU will work as is? even with no EGR? and no repinning?

What I dont get is that the big ALL ECU pinout diagram doesnt list years, just generations. So where would I get pinouts for the different JDM years?


---------- Post added at 02:16 PM ---------- Previous post was at 01:36 PM ----------

Ok I found the 2 diff years on that big pinout list. OK so apparently Id need to repin the harness like this. And what about the missing ones are TE1, TE2, T, THG, OX2. What do I do about these?


09-16-2010, 09:17 PM
Yes your 90 US ECU would work. I don't recall if you might need to send an EGR signal to ground or not...haven't dealt with EGR for a long time now...but I could look it up if need be.

TE1, TE2, and T are all the same thing. In the later revision Toyota renamed it and used two wires. Just route one to the T location and you'll be fine.

THG is the catalytic converter heat sensor. Not required, ignore it. Won't affect anything.

OX1 and OX2 are also the same, they just changed it to OX in the later revision.

09-16-2010, 09:41 PM
Ok ill put the FC back where it was and try my old US ECU and see what happens. Then I will probably repin for the new ECU.

I will either be joyous or be damned. Ill let you know! Thanks

"Our lady of blessed accelleration, dont fail me now."

09-17-2010, 04:29 AM
She started right up!!!! Yeee hawww. Theres couple leaks to deal with. I think one is oil pan so that will suck. But ran it for few minutes. It doesnt really idle, idles very high, Im hoping thats because theres no EGR. So im gonna repin to use the JDM ECU for "more agressive fuel mapping", neat. So, I think I am off and running. All new probs to deal with. !! Har Har. Thanks. If I run into probs with the repinning as usual I'll let you know. All hail Celicatech!

---------- Post added at 10:29 PM ---------- Previous post was at 08:43 PM ----------

If Im gonna repin first I need to know the secret of getting the pins out of the ECU plugs. Even after popping up the deal on the back the pins are still held in. I think I just got lucky with the one I did. Do I need a special tool or something to insert on the front of the plug? Whats the deal? Thanks

09-17-2010, 04:16 PM
First off, :woot:

2nd - the pins. I use a teeny tiny flat head screwdriver. I have a set of them. They might even be for working on eye glasses. But yes, thats the secret. You insert the screwdriver, depress the plastic 'holding tab' that the pin clips on, and pull out the wire. They can be tricky sometimes, especially if you mess up the plastic inside...so be careful!

Or you can get a PNP harness from KO Racing or something that would make it easier. But I prefer things that are free personally.

You will run into one issue - some of the pins are a different size for some reason. The outer ones are larger. So for a couple, you'll have to cut/solder to use the larger/smaller pin. A pain, but there's only a few from memory...I've done it 3 times on my car for various reasons, not too much of a task. Probably took an hour or two tops.

09-17-2010, 10:55 PM
Congratz on getting it going. Repinning for the ECU isn't that bad. Take your time and have both diagrams handy. Look them both over really good before you start. You'll be fine.

09-18-2010, 03:17 AM
Well I figured out the easiest way ever to get the pins out. they pop right out. I moved everything to the 93 spots. Now wont start again. I got spark. I think maybe theres still something screwy with that FC. Running the COR pin 4 to the medium plug. But COR pin 2 gets eliminated by the new ECU diagram, because COR pin 2 on old setup goes to the old FC location But after the repin, G- goes there. So I must have to put COR pin 2 somewhere?? We never did get this question addressed. According to the engine control diagram its upposted to go to the B+ and B on ECU but those pins are used already, and then to the sensors and then to the OX sensor. But I dont know where to splice it in. I think that the COR pin 4 wire that I cut to move it to the FC, that wire goes into the chassis but maybe on the old setup it makes its way to the B's? ----------------------EDIT------------------------
Ok i did some testing. With the US setup, COR pin 4 goes to the B1 and B+ on the ECU chassis plug. The new JDM, I was supposed to cut COR pin 4 and run to the new FC location. Which I did. Fuel pump doesnt come on. So since that cut pin 4 wire to the B's was there, I connected the COR pin 2 to it. Fuel pump still does not come on, I put a contaner under the return hose and its not pumping when cranking. Ideas? Thanks


09-20-2010, 06:18 PM
That is really confusing to read.

Refer to the wires by wire colour. Since we are somewhat unsure which pins do what on yours, that would be easier. Simply make sure the COR is wired in as shown here, by wire colour. Ignore which pins each wire are on the COR for now. Just get the right colour wire to the right place.

The only ones that are of concern as I see it are the black/yellow and the green.


We know that the pins are in the right spot already since it plugged in and worked with your USDM ECU.

09-20-2010, 07:47 PM
If you look at the EC diagram while reading my post you will probably see what Im talking about. It all comes off of that diagram. I put the tester on my COR, pin 1, 2 give no reading like a switch would. pin 2, 4 give about .03 like a resistor or whatever. So I assumed that the pins do what the diagram said but the wire colors were just different. I remembered that I did actually go by the colors the very first time. But that was before I was correctly re pinned for the newer JDM ECU. So I will do that again. I was stripping a celica ST at the junkard last week and I figured id take the COR too, turns out the COR's are not interchangable but the wire colors are the same as mine. 4 is black\yellow and 2 is green. Anyway, I will wire it by color and see what happens. Soon as I get the oil pan back on. Thanks

09-22-2010, 04:40 AM
OK, Im curious why that engine control diagram COR wire colors dont match still. BUT, I could see right away, by moving the green wire pin 2 to the JDM FC location, I could also reconnect my COR pin 4 to the wire that goes to the B+ and B1 ECU pins. AND IT WORKED!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!! She runs awsome. Counter to the diagram which says to put the COR pin 4 to the JDM FC pin. Well whatever works! AND NOW FOR SOMETHING COMPLETELY DIFFERENT, thats python if you didnt know. monty python. Just from running the low mile JDM engine for about 10 min with the US ECU, when I dumped the oil to fix the oil pan leak. There are a lot of big aluminum shavings in the oil. Unless it blows up I dont care. Its gonna be a stock FUN daily driver. I thought MAYBE thats normal for a low mile JDM engine. still getting the casting mole seems out or something. But with my luck probably not.

09-22-2010, 05:42 PM

Definitely seems odd to have shavings in, and usually not a good sign, but best bet is to load it up with oil and a new filter, let it run for a while, then change the oil again with another new Toyota filter. Hopefully that will get whatever the issue was flushed out.

If there is damage there isn't a whole lot you can do without rebuild / replace, so might as well drive it and see how it goes. Might be fine.

09-23-2010, 04:09 PM
Besides the shavings, the cylinder walls looked good and the clutch disk didnt look abused. So its strange, yes. Will see if a couple oil changes help.

09-23-2010, 04:41 PM
Who knows. Could even be that they never had changed the oil from the factory, and it only lasted a very small amt of km's.

I suspect you'll find out very quick if there's an issue. If you drive further than a few blocks without an issue, you'll probably be fine. Heck if it is already idling fine, you're probably ok.

09-24-2010, 02:49 PM
I wish I would have read this a long time ago. I had this same problem exactly and solved it 3 years ago. The harness and ECU have to match revs. It looks to me like you were attempting to use different revs. The FC line is not the only signal that is different. The entire distributer signal set is also different, and a few others. I have posted about this on Ctech before but it was a while ago.

Check this out there is a chart I made regarding exactly which wires have to be relocated and to where.

09-24-2010, 04:41 PM
Yeah, we figured that out, however made the mistake right off the bat of assuming they were both of the same revision. You've summed up the conversion pretty good though in that thread.

09-24-2010, 09:36 PM
A great thread to read for "educational purposes".

Before this - I had no documentation at all of actual wire colors for the 3SGTE cars - only for the 5SFE cars.

90ToyAlltrac - great to hear you got yours going - I just went out and started mine again to make sure it would still start! :)

Still - I have my "homemade starter relay" in my center console until I can find where my harness was hacked.

Congrats and enjoy!

09-25-2010, 07:19 AM
Yeah, wire colors that dont match the diagram. ugh. I WILL enjoy it now. Just gotta get the exhaust on cause it wont fit from a GT4. Slight mods needed. Paint and put some widebody fenders on. Get the engine bay undercovers on. and the fender well covers in. The hole thing is getting it prepared for a Fargo winter. The carlos sainz bumper is gonna fill up with snow and turn into a giant ice block unless I just dont drive it for those 3 months. As far as the metal shaves in the oil I realy think its possible this engine is so low miles that there really is no prob. Ive driven it umpteen miles so far. More when I get the hood and fenders on. Let you know.