Inconsistent starting 2014 370Z (6spd)
 

As the title suggests, I noticed yesterday there's been inconsistent starting. It happens even more so after driving for some time.

I was below a half a tank so I did fill up to full (after having to use a gas can) thinking it night be related to the fuel pump issues these cars are plauged with.

But, even with a full tank and checking the battery terminals, sometimes it starts, sometimes she doesn't. I press and hold the start button while pressing the clutch like normal and it just turns the radio and AC on, I hear the fuel pump activating when I press the button again but she won't start up.

I'm a bit confused considering she hasn't even reached 50k miles yet so I figured it couldn't be the starter going bad or the spark plugs going bad. It just does not even attempt to start the motor at all and there's clearly power from a 1 year old battery. Also, I did recently change the battery in the fob but I don't know if that has to do with this. Any ideas whats going on here?

So the symptom is sometimes crank, sometimes no crank at all, correct?

Correct. Full tank of gas, practically new battery, new fob battery (but it's weird that this started happening after changing the fob battery). I was driving around for some time below a half a tank of gas until I filled it up.

Faulty clutch switch?

I did not think about this, I read around after you mentioned it and I tried starting it again today and it's always telling me to push the clutch in even though I'm pushing it in. It started 2 out of 10 times I tried.

Do you know where the switch is and how to replace it?

It's a switch on the upper backside of the clutch pedal. It's adjustable on the original clutch pedal, I think? Should just loosen nut and rotate switch out a bit so it gets depressed all the way. Most of us have the RJM clutch pedal replacement though.

This. I also have the RJM pedal assembly, but I fully suspect that the switch can be adjusted on the stock assembly. You will have to get down into the driver's footwell and get access to the switch. The space is tight. The switch screws into the assembly bracket and is held in position with a lock/retainer nut. If I recall correctly, the nut is a 14 mm. Loosen the nut and spin the switch out 1-2 turns and see if that helps. You may have to disconnect/unplug the wiring to the switch to allow it to spin. There is a release tab on the wiring connector that you'll need to depress while gently pulling the wiring plug out. Once done, re-tighten the nut, re-connect the wiring plug, crawl back out and test it. Also, note that there are two switches mounted on the assembly bracket ... the clutch switch as well as a cruise control switch. It should be obvious which is which. If I remember correctly, the clutch switch is the lower one. If the problem persists after the adjustment, it could be that the switch itself is defective. Trust this helps.

Sorry, but it's been a few years since I fussed with the pedal assembly. Upon further reflection, I don't think that the switch actually screws into the assembly bracket, but rather it's held place with two nuts. In other words, the bracket itself is not threaded. Instead, the switch mounts through a hole in the bracket and is secured in place by two nuts ... one on each side of the bracket. It will be obvious once you see it. Good luck!

Thank you everyone!! I'm going to tinker with the clutch switch to see if that's the issue this weekend but I'm seeing a theme that I should probably switch to a RJM clutch pedal assembly.

I always thought I did all of the upgrades to prevent any reliability problems like the oil cooler, changed to a heavy duty CSC, upgraded the radiator but I guess not. I skipped the fuel starvation upgrades because I usually just keep a full tank to prevent that most of the time.

No worries. Note that you may not need to unplug the wire leading to the switch ... but unplugging it and moving it aside may give you more room to fiddle with the two nuts holding the switch in place. You will want to adjust the switch such that when the pedal is depressed, the spring-loaded pin on the switch is fully depressed against the rubber bumper pad. You can check this while you're in the footwell by grabbing the pedal and pulling it downward and making sure that the pin fully retracts into the body of the switch. In fact, this should probably be your first step. Get into the footwell and depress the pedal and determine if the pin fully retracts. If not, then proceed to adjust the position of the switch as described above.
Again, sorry for any confusion. Things should be obvious to you once you start examining the pedal once you're in the footwell.

You are the real McCoy, got under the foot-well unplugged and unscrewed the old switch, installed the new one and no issues at all. Started up 5 out of 5 times like normal and it was only a 5 minute operation. This tiny issue should definitely be up there with the CSC, limp mode and fuel starvation failures.

I just adjusted the switch exactly in the position how I saw the original before I started unscrewing it and no issues at all. Thank you so much for your help!

No worries ... glad to be of assistance. Actually, I carry a spare switch in the car (... along with tools) in case it fails. As you discovered, it's relatively simple to change out/adjust if ever needed.