350z doesn't start when warm start
 

Hi, I have a 2005 350z 6 speed

Been through a lot but my most recent headache is that when it's a hot day, and the car has been running a while..maybe a 15+ min trip, if I turn it off it won't start back up.

It starts up, sputters slightly, then dies within one second. Throttle doesn't respond. Sometimes it doesn't start up at all, just crank. No way to get it to start besides letting it cool.
I recently put a used ecu in it,it came from the exact same car and it was good for a few months. This only started happening last week.

Cleaned MAF, cleaned throttle body, one time I did the accelerator relearning key sequence and it started right up but after that, never again.
No codes showing besides o2 sensor.

Does anyone know where I could even begin? Much appreciated.

I assume you replaced the oxygen sensor, and that did not repair the problem.

I have not..do you think that could cause it?

A faulty oxygen sensor could cause the problem you describe. It would be intermittent, but that is what you report.

But more likely… Your car fails to start because of fuel starvation. The o2 sensor is reporting this. Check the fuel pump. If it’s weak, you might be getting a vapor lock.

Your problem could be caused by so many things…
--Spike

I'm just afraid it's electrical.

I put a new o2 sensor in, next time it happened I planned on checking the fuel pump and going from there.
Thanks for your help

The o2 sensor did not fix the problem..

It's now gotten worse, if the car warms up at all and I turn it off, it absolutely will not start back up until it's all the way cold. Only CEL code is for the driver side converter.
The car starts but dies real fast then just keeps cranking. Doesn't respond to throttle. Fuel pump works as the engine does, it turns real fast then stops.
Does anyone have any idea what it could be since it's gotten progressively worse?

I know you said you cleaned the Throttle Body, but I had similar issue before on my 08 HR. It turned out that my driver side Throttle body was stuck, after two days of trying to fix other issue. I pushed the valve open to free it up on accident then the car started right back.

Did you touch the butterfly when cleaning the TB. You might need to reset it(no idea how, but I'm sure you can Google it)

Wouldn't that lead to a permanent issue? Although I'll check tomorrow to see if it's stuck when it starts acting up. I appreciate it

I did relearn it once, didn't make a difference..I'm leaning towards a throttle body or fuel pump issue.

Same problem
 

Hey guys, I know this is a very old thread but I wanted to put this hear to help other if needed, my issue was my 350z once it got hot unless left to cool off had a very hard time starting up and would if very hot, not turn over, after much research I took apart and cleaned my air filter, MAF sensor, and throttle body (though these were already quite clean, I then went to replacing my O2 sensors, which did not fix it, my next step was going to be the fuel pump (found in research) until I found a thread talking about the Coolant Temp Sensor, after some install research I found this to be a pretty easy install and quite cheap part so I snagged one and threw it in, my MPG went from 16.7 to 23.2, my car no longer has any issue starting up at any temp and there is no longer even the slightest stutter when idling (which I didnt even really notice until it was fixed). Hope this helps anyone finding themself with this issue!

I would have never thought about looking to the coolant sensor. That's an awesome find. I will keep that in mind.

I have this exact issue, we're your symptoms sputtering and struggling to start when warm and also a feeling of lack of power occasionally, like it was holding itself back? It never threw a CEL though.

Hello guys, I hope you are all well, just following up on this, I seem to be having a very similar problem only thing is, cold start the car starts perfectly fine no issues at all, but if I drive it and then let it stand for and hour it cranks quite long before it starts but if I leave it to stand over night it will start right up again. I have been struggling with this and no one in my area seems to have the knowledge how to fix or where to start..I am at my wits end on this..the car preforms perfect etc so I don't know what to do

My guess would be camshaft sensors. How many miles and year?

2005 model 160k kilometers, if it was a camshaft sensor why would it recurringly only do it after its warm and stood for a while? Iv taken it 3 mechanics now and they can't figure it out

A buddy had the same issue, it was the sensors

I'll try this next

literally tried everything and changed all sensors all pumps all every thing and it's still there and at this point it's just costing alot of money.

Does anyone have an idea?

Hey did you ever find a solution? Having the same problem and it has gotten worse.

I tried almost everything listed above except for Coolant temp Sensor but I checked mine with an IR thermometer against OBDII and it was ok. Thanks