What’s up guys new to this forum. So I have a 2003 g35 sedan auto and the engine has rod knock .. layer out my possible ideas and I’m just gonna drop a new motor in it.. BUT I have some serious concerns. if I buy the US DE what are some things I should do to the motor before dropping it in so it doesn’t blow up like my last @159k miles. I was driving and it slowly died thought it was the alternator .. jumped it .. then it started knocking .. oil was fine and there’s was no leaking .. anyways you guys think I should do timing on the new swapped engine and all that good stuff or usually the engines come just drop in and your good . Also was looking at the JDM engines . Would that fit the American trans even tho they have different wiring harness / ecu ? Lmk

 

They use the same wiring harness and ECM. Everything was manufacturered in Japan and then shipped overseas to the US.

Just make sure you are getting the correct VQ35DE, not a rev-up, not a transverse mounted one from a Maxima/Altima/ETC.

 

As for things to do to prevent rod knock, check your oil level regularly, that's by FAR the most common reason for destroying the connecting rod bearings.

 

From the pictures on the “JDMENGINEWORLD “ comes with the ecu with the engine should I just scrap it and use my old one ? And should I change spark plugs , coil packs, starter, etc knowing that stuff works rather then guessing the stuff came on the engine from Japan works ?

 

Use your original ECU + harness.
For the new JDM engine, minimum replace the spark plugs. Check all the accessories for wear/leaks before installing and address as necessary.

 

I would swap over all coils, sensors and stuff like that since you know they're working on the existing motor. Keep them though, particularly the cam/crank sensors so you can use them as a replacement in the future when yours fail. Probably keep your existing throttle body as well, just be sure you aren't working the butterfly plate by hand when you take it off.

Probably leave the knock sensor but see if you can replace the sub harness for it while you have the engine out. It's a known failure point so might as well put a new sub harness in.

You will need to perform the throttle closed position relearn, same with the idle air recalibration. It's in the FSM under section EC - Engine Controls at the start of the document under "basic service procedures".

 

+1 Check/replace the knock sensor harness. Its a lot of work to get to it, changed mine a few weeks ago.