3rd Gen 3S-GE swapping information thread, Use your old harness w 2/3gen swaps? Options

[H8TRAIN]

Wiring for Non-Turbo 3SGE swaps into Celica ST204 is undocumented. Strange but true. As of today, we have two 6gc members (KAOS and mi645) attempting the 3rd gen 3sge swap with no information on how to wire them.

I understand that the swaps have been done and are not difficult. I’m starting this thread in hopes that those with the experience can answer some questions about these swaps. The details of the wiring all follow from one primary question.

Question: Is it best to use a 5sfe harness to swap in the 2/3gen 3sge?

(Reminder: 3sge means non turbo or na. Without a ‘t’ in it. Not 3sgte. Normally aspirated.This thread is about the 3sge, NOT the BEAMS. That is not a typo. Atmo. Strictly vacuum. Sucker not blower.)

Following are the threads and posts that lead to this question.

This was posted on here by 99gt3sge

you can use your 3s harness, i did a swap for my friend using a 3rd gen 3sge non beams with his original 5sfe harness, i had to wire up two injectors, re-pin the dizzy, and re-pin the ecu plugs to run the ge ecu. and extended some of the tb plugs and wire in the acis solenoid. it's not as easy as wiring a honda but it's very doable.

From eazy2001x on mr2oc:

thats a Gen 2 celica engine, your better off using a 5S harness and modding it to work.

From user pimpm3 on mr2oc:
Sadly, the image of the wiring changes that he made seems to be lost on the internet. I tried waybackmachine. No luck.

I had a hard time finding the exact instructions on how to wire in a 2nd Gen 3sge into a 1991 Na car, so I made a chart that shows how I did it. I hope this helps.

The 26 Pin and 16 Pin connectors plug straight into the ECU from the engine harness, the only wiring I had to do was on the 22 Pin connector. I took the wires from the 14 Pin Body harness conector that and soldered them on as follows to the 22 Pin connector so it will fit in the 3sge ecu. I labeled the wires on each conector before I cut them and then all you have to do is match them up.

The car starts right up and runs great. You can hook STA from the 22 Pin Connector up to the starter relay if you like but I did not and the car starts fine with out it.

Open questions for anyone who knows:

Can the 5sfe celica wiring harness be used on a 3rd gen 3sge swap?
If so what changes must be made?
Is it simply an act of opening both ecus, looking at the printed diagrams, and matching them up?

The 3rd gen motor is supposedly the easiest to install but is the 2nd gen really any harder? Can not the 5sfe harness be modified slightly to run the 2nd gen engine and ecu? Again do the ecus need to be simply opened to reveal the key to matching a few pins?

Any info and thoughts appreciated! There are people out there right now trying to find this information! I know I have been asking around for weeks now!

[99gt3sge]

Wiring for Non-Turbo 3SGE swaps into Celica ST204 is undocumented. Strange but true. As of today, we have two 6gc members (KAOS and mi645) attempting the 3rd gen 3sge swap with no information on how to wire them.

I understand that the swaps have been done and are not difficult. I’m starting this thread in hopes that those with the experience can answer some questions about these swaps. The details of the wiring all follow from one primary question.

Question: Is it best to use a 5sfe harness to swap in the 2/3gen 3sge?

(Reminder: 3sge means non turbo or na. Without a ‘t’ in it. Not 3sgte. Normally aspirated.This thread is about the 3sge. That is not a typo. Atmo. Strictly vacuum. Sucker not blower.)

Following are the threads and posts that lead to this question.

This was posted on here by 99gt3sge

you can use your 3s harness, i did a swap for my friend using a 3rd gen 3sge non beams with his original 5sfe harness, i had to wire up two injectors, re-pin the dizzy, and re-pin the ecu plugs to run the ge ecu. and extended some of the tb plugs and wire in the acis solenoid. it's not as easy as wiring a honda but it's very doable.

From eazy2001x on mr2oc:

thats a Gen 2 celica engine, your better off using a 5S harness and modding it to work.

From user pimpm3 on mr2oc:
Sadly, the image of the wiring changes that he made seems to be lost on the internet. I tried waybackmachine. No luck.

I had a hard time finding the exact instructions on how to wire in a 2nd Gen 3sge into a 1991 Na car, so I made a chart that shows how I did it. I hope this helps.

The 26 Pin and 16 Pin connectors plug straight into the ECU from the engine harness, the only wiring I had to do was on the 22 Pin connector. I took the wires from the 14 Pin Body harness conector that and soldered them on as follows to the 22 Pin connector so it will fit in the 3sge ecu. I labeled the wires on each conector before I cut them and then all you have to do is match them up.

The car starts right up and runs great. You can hook STA from the 22 Pin Connector up to the starter relay if you like but I did not and the car starts fine with out it.

Open questions for anyone who knows:

Can the 5sfe celica wiring harness be used on a 3rd gen 3sge swap?
If so what changes must be made?
Is it simply an act of opening both ecus, looking at the printed diagrams, and matching them up?

The 3rd gen motor is supposedly the easiest to install but is the 2nd gen really any harder? Can not the 5sfe harness be modified slightly to run the 2nd gen engine and ecu? Again do the ecus need to be simply opened to reveal the key to matching a few pins?

Any info and thoughts appreciated! There are people out there right now trying to find this information! I know I have been asking around for weeks now!

I have done two 3sge non beams swaps, one of them i used the 3sge harness and the other i used the 5sfe harness.
first off, If you have the complete 3s harness then everything is basically plug and play. the things i had to do was remove the the plastics that cover the harness in the rear section of the harness and then it frees up some extra length which allows you to reach the the ecu plugs. aside from that i extended the ignitter and coil wires to reach the fire wall. and i also extended the intake sensor that goes into the air box. also there's one wire that is missing from the engine bay fuse box which i believe its for the airbag, it's up too you if you run this wire. this method is way easier than cutting the harness and extending it. and lastly since my car was an auto i had to jump the wire from the neutral safety switch so my car would start and wire in the reverse switch. other than that everything is plug and play.

The second swap i did i used the original 5s harness because the 3s harness had the fuse box wires cut off, and the dash plugs cut off. So i compared the 3sge harness and its basically the same lay out. first of all i sourced the ecu plugs form a s/c previa, it has the same plugs as the 3s. then i re-pinned the ecu wires to match the 3s diagram. now since this car was a federal car the injectors are wired a bit differently than a cali car. i basically had to to wire two injectors to the ecu plugs. for the reason that the 5s injectors share wiring signals. then i wired the acis solenoid to the ecu, i also wired in the 02 sensor. i used the two wires from the 5s 02 sensors and added one wire in. after that i laid out the harness on the engine and i had to make sure the plugs reached the throttle body and the sensors that go on the water neck. and also i had to re-pin the dizzy wires, there in different location. Basically all the plugs that go to the engine are the same as the 3s, after doing both swaps i preferred using the 5s harness due to the fact that the car with the 5s harness idles smoother than my car which is using the 3s harness.
over all since i have wired hondas, 2jz's, sr's this swap would have been easier if i had better wiring diagrams. but that my 2cents.