Greetings, all! It's been ages since I have been out here (having long ago sole my Z). My fiance now owns a 2003 350Z track and lately there is an issue with car cranking.

This started with the car taking a little longer to crank over time (a few weeks) to the point now, when you turn the ignition key, the motor just turns but does not fire. Looking for some input on possible culprits so we don't start replacing things we do not need to. Unfortunately, it appears the prior owner disabled the error codes so we have no input from that on what may be wrong.

We have recently replaced and/or tried...
- replaced MAF sensor (and confirmed it is not soiled/wet/dirty)
- confirmed O2 sensors are not bad
- replaced fuel pump and sending unit
- have reset ECU

Any thoughts on other things to check?

 

How did the former owner cancel the diagnostic system? If this 03 track model is still using the factory ECM, I'm not aware of any way to disable the diagnostic side of things. Also, list the mileage and any powertrain mods that might be involved.