Hey Z gurus,
I'm having an intermittent starting problem with my 350z. I've searched plenty but haven't come up with an answer, as my situation seems different than the others.

Background:
I totalled my 2007 350z. Instead of letting it rot away in a junkyard, I bought it back and purchased a running 2004 350z. I swapped EVERYTHING from the 07 to the 04. Engine, Transmission, ECU, all wiring harnesses, interior, subframes, all that. In the process, I took an APS VQ35DE TT kit and made it fit the HR.

Engine mods: (Since this may be relevant to the problem)
OEM longblock
OEM ECU with UpRev Tuner and tapped for knock monitoring
APS Twin Turbo Manifolds, Turbos, inlets, O2 Housings
Dual 3" turboback exhausts
twin intercooler and charge piping
Billet fuel rails
SIR 1150cc injectors (for GTR)
Walbro 485 in custom hanger in passenger side
OEM pump in driver's side (to flow fuel across)
6an feed lines, OEM feed as return
Aluminum radiator
30 Row oil cooler with thermostatic oil plate
extra engine grounding locations.


The issue:
When the car is running, it runs fine. No stalling, hesitation, or anything. I'm not entirely done tuning it because of the starting issue, but it's drivable. The problem, however, is actually getting the car started. At first the issue was only when the car was warm. I could start it cold, drive it as long as I wanted, then turn it off. Once I turned it off, however, I couldn't start the car again until a decent amount of time had passed and the car had cooled down. When I turn the key, I get one "chug" of life then it just continues to crank without firing. I can keep cranking, but it doesn't fire to life. My fuel pressure stays at a steady 50-60psi throughout.

The other day I was driving it and ran out of gas and died (fuel level sensor isn't hooked up right in one of the tanks so the gauge isn't working). I restarted her a few times to drive to a safe location, then pulled my jug out of the trunk to add a few gallons. After filling, with the car still warm, I was able to start it and drive away. For a moment I thought my hot-start issue had disappeared.

Now, I've got the car parked in my garage, cold, and it's doing the same no-start situation. I've tried resetting the ECU and everything, but no luck. One "chug" like it's going to start, then endless cranking.

Thoughts:
I'm suspecting a cam or crank position sensor, but I haven't gotten a code for any of those. I've read on here that the sensors can act weird once they warm up, which is why I suspected this.
The only codes I've gotten while driving the car are for the fuel level sensor and knock input. I'm not getting any knock while driving, but it would come on when I first start the car. I suspect it's the loud injectors or from my charge piping hitting the frame rail.

tl;dr: crank crank crank, no vroom.

Any help would be appreciated!

 

change the camshaft sensors, they dont always throw a code (a buddy of mine his never threw a code)

 

So you swapped an '08 drivetrain over to the '04 chassis? I wonder if you could be running into a NATS issue. That's a tricky swap (ask me how I know) and I wonder if there's any factor that could trigger the ignition cutoff? But you have quite a few variables (engine, FI, etc) that might be involved as well.

 

Would a cam sensor cause it to not start at all, or just run poorly? Is there any easy way to tell which one it may be without having to replace all four? Like maybe unplugging one at a time to see which affects it the worst.

I swapped in almost everything from the 07, including the entire wiring harness from the car. BCM, Door and hatch locks, steering column (with lock assembly). There were no electrical components left in the 04 before I started swapping in the 07 stuff.
That said, I have thought it could be something with the NATS, especially since the car sat for a while during all this work. I find it odd that it only stops me sometimes.

 

If if is the nats system, your tuner can disable it with new Uprev flash.

 

I'm tuning it myself, so unfortunately I've only got the Tuner version of Uprev. (which doesn't have the option to disable NATS)