2005 350z Occasionally Won't Start
 

My 2005 305z occasionally won't start (it does crank) and I was wondering if anyone else has experienced the same problem.

Here are some more details:
- Car: 2005 350z 6MT, 41K miles and driven about 2 days a week in Los Angeles.
- When does this happen: Starts fine for a month or so and then after being driven somewhere (not the first drive of the day) it won't start for some period of time.
- When has this happened most recently: Today after driving to grab breakfast and returning to my car.
- What happens: Car cranks and you can hear the sound clearly. There seems to have plenty of power to the car. Eventually, the car will start but the amount of time will vary. Today, it was over an hour and I had to have AAA tow me. After dropping the car off at my house, it still wouldn't start. About an hour after leaving my car parked near my house, it started just fine.
- What have I attempted: I did have a battery problem (according to AAA) about 5 months ago so I replaced the battery and cleaned the battery terminal cables of any build up. I've tried removing the keys and re-inserting them and trying to start the car immediately as well as leaving them in the ignition for a moment before attempting to start. I've tried checking the battery cables and wiggling them.
- What have I noticed that may be of note: The car is sitting in the sun typically when I have a problem and it is a little hot.

I'm at a bit of a loss here.

I've seen these posts:
- https://my350z.com/forum/other-vehic...ont-start.html
- https://my350z.com/forum/maintenance...sometimes.html
- https://my350z.com/forum/maintenance...-randomly.html
- http://www.10w40.com/questions/auto-...urns-over-like

I was going to try flipping the key over as well as bringing my spare with me just in case it is a key issue (as I've read this could related to the immobilizer). For this to be intermittent, I think it points to an electrical problem and perhaps some sensor issue. I as thinking of buying an OBD2 reader and taking that with me to help diagnose (any suggestions on a specific device would be appreciated).

Any suggestions overall would be greatly appreciated. Thanks.

Cheers,
David

It could possibly be something with the fuel system. When I had my 95 camry back in high school I was dumb and thought if I bought those fuel injector cleaners and got 93 octane my camry would get more horsepower =P. After doing that it wouldn't start sometimes and I had to keep pressing the gas pedal while cranking so it would start. After I got a tune up and stopped putting the fuel injector cleaner from the gas station and stopped buying 93 octane it would start just fine with no problems all the time. I wasn't certain it was a fuel issue but I have my suspicion it was so that might be the same issue with your Z. When was the last time you had a tune up?

Could be your cam position sensor.However,they usually don't go bad with
the miles you have on your car.When one starts getting weak,you will not get a
CEL.

+1 on the camshaft position sensor. I just changed the CPS on my girlfriends murano with 60,000 miles on it that had similar symptoms as you just described. Runs great now.

Yeah, it could be fuel system related. From what I've read there may be many things that trigger how the fuel system kicks in.

I've never put any fuel injector cleaner in my car and I've read bad things about it from others as well. I've also never given the car a tune up. I don't see it on the schedule here for the 2006:
http://www.nissanusa.com/pdf/techpub...2006_N_SMG.pdf

How did you know it was specifically the Camshaft Position Sensor? Did you decide that it was fairly inexpensive to replace and therefore a good guess?

i have this issue occasionally, after a drive ill turn it off, then go to move it, say out of the gas station, and it wont start. i try to leave the key on the on position for a second because ive read of the key not being recognized or something. that usually does it for my car.

It's none of those things.

Well that certainly clears things up........

I found out it was the camshaft position sensor because it finally failed and threw a code. I found the sensor online and replaced it for $35. But like JCity said, the sensor could be malfunctioning without throwing a code, so it's hard to be certain. There is one on each bank BTW incase you decide to do the guess and check. Good luck with the diagnosis.

Check all of your main grounds. A loose ground can cause intermittent starting problems like you describe.