I have a blown H23A1 engine and I bought a H23A3 engine. I noticed that the wiring harness was a little different. Will the harness from the old engne work on the H23A3? I read that I will need to take the distributor and external coil off of the H23A1 and install it on the H23S3.
Is there anything else that I will need to swap or purchase to get my car back up and running? Any advice or help will be greatly appreciated.

 

read the FAQs at the top of the page. you are not doing a swap, you are doing a longblock replacement. if yo uar not sure what exactly to do, take your intake and exhaust manifolds off the original engine as well as teh harness and distributor, and put all that on the new engine and put it in the car.

 

Thanks I'm an old VET and havent done anything like this before.. I got it.. What I have learned so far is swap the intake & exhaust manifolds. Swap out the distributor and the engine wiring harness and the power steering bracket. Also install a knock sensor in the new block. Is there anything else that I need to do before I drop it in?

 

just do it like its a long block replacement on any car. I would do the same process on a Chevy, ford toyota or nissan. you want all your sensors and harness from the original engine/car there so the computer that you are re-using will be happy and have the engine run right, and you know the harness will fit the car without an issue.

 

Thanks!!

 

I replaced the H23A1 with a H23A3 long block. I used the H23A1 engine wiring harness, intake manifold, exhaust manifold, distributor, knock sensor, alt bracket, power steering bracket, ac bracket and installed all of these items on the H23A3 long block. Everything swapped over and fit fine.
I now have more problems. The JDM H23A3 used engine that I installed is blowing out a ton of white smoke and its idleing crazy. The idle goes up and down up and down. It is also blowing some coolant out of the radiator neck. All indications of a blown headgasket but I'm not getting any coolant in the oil and I'm not sure why the coolant isn't in the oil.
If anyone has any ideas as to why I dont have coolant in the oil and why the idle is so erratic please let me know. Thanks

 

The oil passages are probably still sealed, but the coolant passages right next to the combustion chamber are likely blown. Sounds like you need a head gasket.
As for your idle, there is air in you coolant system. Make sure to bleed it properly after you do your head gasket.

 

Thanks. I got the idle problem under control. I bought a can of Carb cleaner and sprayed it around the intake and found that my son didn't tighten up the intake mount nuts. Idling problem solved. There isn't a ton of white smoke anymore and no coolant in the oil. The headgasket may have a small leak but I need to do a pressure test to confirm.