Engine Identification

I apologize if this has already been addressed, I thought I remembered a post about it somewhere, but I can't seem to find it.

I bought a car with a swapped engine an I want to verify which variation of the 3GSTE it is I have exactly. I have a couple pictures, but I'm not sure how usefull they'll be. Is there a code on the engine or significant differences I can look for to determine what exactly it is I'm dealing with?

https://www.dropbox.com/sc/88nkka0elovobyd/-vJOKbzmKh

https://www.dropbox.com/sc/fho8l66dujt3z5f/3l0hEMFCrN

https://www.dropbox.com/sc/gvjbe7iobxdqlut/6Yksgh_D9j

Gen 2 3SGTE out of a ST185 celica GT4/Alltrac. Gen 2 engine was available in the ST185 and MR2 1990 - 1993.

Gen 1 3SGTE in the ST165 GT4 had a water to air intercooler
Gen 2 3SGTE in the GT4 RC/Carlos Sainz edition had a water to air intercooler
Gen 3 3SGTE in the ST205 had a water to air intercooler (though there are 2 versions, 1 standard, 1 with fake antilag setup)
Gen 4 3SGTE in the ST215 Caldina has an air to air top mount intercooler with side manifold
Gen 5 3SGTE in the ST246 Caldina has an air to air top mount intercooler with centre feed manifold

Gen 2 3SGTE from pictures because:
- oil filter is on the block
- top mount air to air intercooler
- rocker cover probably has a right angle hard pipe on the drivers side of the rocker cover
- Throttle body diameter is 55mm? (someone can correct me on this)

There is some identification that notes it is a 3S on the block, above the gearbox, just below the head, but the serial number doesn't signify anything (not that I've read anyway)

You may have an engine swapped out of an MR2, but with all the Celica mounting hardware for the PS pump, alternator, and AC. I would assume that it is a straight swap, so the engine would be out of a Celica, not the MR2 (can't do straight swap between Celica and MR2 because of aforementioned brackets/locations of ancillaries).

Sweet. Thanks. I was also told it was a JDM engine, is there anyway for me to check that? I do have a second ECU hanging out in a box of parts that came with the car. The guy that sold it to me told me that it was JDM but running the USDM ECU, which seems a bit odd to me but I didn't argue because I was in Afghanistan at the time and my friends were the ones that actually interacted with the seller.

JDM engines don't have EGR.

It's a 90/91 JDM engine.
US ECU will run that engine just fine.
You probably are using a USDM harness too. Assuming you have no CEL.

Awesome, thanks guys. I just wanted to make sure somebody didn't pull a fast one on me. If this were a 4A I'd be ok, but the 3S is a new beast to me.

Now for the logical follow up question. Is there going to be any large advantage to switching over to the JDM ECU and if so where do I find information on how to do that swap? Just need a point in the right direction.

The JDM ECU is up to 25 HP more [if you run 94+ octane].
It's a direct swap for the US ECU [has to be the same revision, 90/91 or 92/93, or you'll have to change a few wires], but a US 4 wire O2 sensor won't work right because the JDM ECU can't control the heater in the O2. You can either swap to a single wire O2 sensor or ground the heater wire from the O2.
Engines to ECUs don't matter, either revision works fine with the other, the wiring harness is what causes problems because of a few different connectors and some different wires.
Easiest way to tell which revision harness is look at the short harness for the alternator; pre revision has an oval plug between the alt harness and engine harness, post revision has a triangular plug.