Okay, so ill start off by saying my old engine (2005 vq35de non-revup) spun a bearing and i put a 2005 vq35de (also non-revup) back in the car. Here's the kicker, the new engine was from an automatic g35 coupe. I am still using the original ecu and wire harness from my old engine so everything bolted right up and every sensor was plugged in. The engine will crank but not start. I tried plugging up my Osiris tuner in, but it couldn't find the ecu! We also tried using a snap on scanner and that couldn't find the ecu either. So, the ecu is not getting power. I tried checking the fuses but they all looked good. I know most of you will ask "did it throw any codes", and my response will be, no. It won't throw a code because the ecu has no power. So, if the ecu is not receiving power but the car is cranking, could that be NATS giving me problems? I know the car won't supply fuel and probably ignition with Nats, but is there some other way i could diagnose this? The Fan kicks on very hard after just a few seconds of the car being on the "On" position, even though the engine is cold. I'll have to double check but i think the led on the dash blinks or stays on solid when it's on the "ON" position also which would make me also believe it's the NATS system. For people who have used the NATs delete, how did you do it? I don't think i can disable it if my ecu doesn't even have power. I am at a lost of what to do. So please help. Thanks.

PS: I did use the search engine.

 

We have the same problem. My car just suddenly died. Only 1 plug fires whenever it's cranked. Everything else look fine, according to the scanner.

Will keep you updated if there's any luck.

 

sounds good, i just don't know what it is. Its killing me, i want to drive the damn thing already haha.

 

tell me about it. It's fawking frustrating. Been 2 days now. We changed crank sensors, coils, plugs, all you could think of. Still no luck.

My mechanic will start checking on the harnesses, etc tomorrow.

 

yea, thats what i was plan on doing today when i get off work. Have you guys checked the position of the flywheel? I was told that if its put on wrong the car won't start. I really don't feel like taking the transmission off to check this. I am going to try everything, and if i cant get it, that will be my last ditch effort lol.