Okay so bought a jdm f23a1 to rebuild (top-end only) usdm f23a...kind of screwed myself I feeI. I have a vacuum line coming from the fuel rail I have no idea where it goes a couple sensor plugs that seem to go nowhere, and the whole thing is back together except for that vacuum line and the sensor plugs any idea what it could be? Not too worried about the sensors (there’s one on drivers side and one on passenger) But I could see it throwing a code or causing issues after some drive time, any help on any differences would be awesome in the sensors (I already know not to use usdm plugs with jdm sensors or vice versa)

 

Although the core engine is the same, a lot of little things are different. The exhaust manifold will be different, as well as the top of the intake manfold. Swap those. Also, swap the injectors and rail over together because they are probably different sized.And , of course, swap over all your USDM sensors and don't use the JDM ones.

You will be good to go if you do this.

You are also right, some sensors really don't go anywhere, just a wire to it and then it's bolted to the engine.

Vacuum lines (I'm going from memory) could be underneath the intake manifold, there are also the coolant lines that run to the underside of the intake. Sometimes easier to see clearly if you go under and look up rather than try to feel for it from the top.

 

Also, take pics and post of the areas of concern. That will help us identify what you are looking at ,

 

okay so I did swap the intake and exhaust manifold I’m honestly not sure if I did the fuel rail but it went right onto the old fuel injectors and all the bolt holes lined up but could that be where the extra fuel vacuum line came from? It goes up on drivers from the back, and has three little clips it fits into that hold it in place,but the clips are at the very top of the engine on the valve cover and it loops around to right in front of the throttle body on the passenger side, I will post a video tonight when I get home showing but i hope that helps explain it a little better, and I’m pretty sure it’s two extra sensors I have I shouldn’t worry too much about those? And just one more thing I posted in another thread but haven’t got any replies on it since I posted it three days ago but when I took it apart it wasn’t far off from tdc cyl #1 do I need to worry about timing my balance shaft?

 

I'd probably remove the sensors and throw them away if they weren't part of your original setup, and make sure to fill them with a plug if they going anywhere (which should have been on the original.

vacuum lines could be leading to valve cover, throttle body etc. If you can post that picture, we can post comparitive photos so you can see where they go.