Car won't start only during hot weather

ZNismoZ

I have a 2012 370z touring sport package with 55k miles.
Only when it's hot outside, never had an issue other than summer. It usually happens multiple times in the summer when the car is in direct sunlight.

When my car is outside in the hot sun it will not start. A few times when I was actually driving, I felt a lack of power, car sputtered and died and would not restart.

When trying to start or restart the car, it sounds like it wants to turn over. If it does catch and turns over, it will quickly sputter and die. I have to wait a few hours until it is cool inside the cabin, then the car will actually turn over and drive.

I have changed the map sensor already, thinking it was related, due to a code. Cleaned throttle body and maf sensor due to code.

This has been going on for a few years. Currently no codes. This issue happend about two hours ago
after driving to my local hardware store. The car drove fine, parked the car outside the hardware store in the hot sun for 30 min, and could not get the car to restart after.

The car eventually turned over about two hours later, the windows were rolled down and cabin temp was significantly lower compared to when I came back to the car.

I am not sure if this issue ever happened when the engine is cold overnight, but started first time in the hot sun. The car engine temps are normal according to the gauge, and enough coolant. I had issues with my Honda civic 92-95 in the summer, it ended up being main fuel relay switch. Any help would be appreciated.

Woketman

I doubt this is the issue, but it is worth stating. My old 1981 (I think) 280ZX used to vapor lock pretty consistently in the hot Louisiana summer. If I drove it to the store, heating it up, when I came out she would not start. The fuel in the line near the engine had vaporized causing vapor lock. I would open the hood, wait 15 or 20 minutes and viola, she starts!

Not sure if a modern 370 can still have this issue.

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Spooler

Sounds like a fuel pump acting up. Need to test the fuel pressure when it happens. You can get a gauge you can add on.

www.cj-motorsports.com has the adaptor and gauge you can put under the hood of your car.

https://cj-motorsports.com/products/...p-4-way-2-bolt

It may be the 2-way one. I can't remember.

SouthArk370Z

I don't think I've seen this problem on this site before. I'm inclined to believe that if it is a heat problem, Woketman's suggestion to pop the hood for a few minutes would be worth trying. Spooler may be on to something but I would think you would get a DTC of some sort (maybe not, like I say, I haven't seen this problem reported before).

I can't imagine what piece of equipment could be in the cabin that would cause your problem. If it were a no crank situation, the security system would be a suspect. I'm guessing that cooling of the cabin helping out was coincidental.

Good luck figuring it out.

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ZNismoZ

I will try opening the hood next time it happens, and see if that helps. Good idea

ZNismoZ

I was thinking fuel pump as well. I will buy that, so I can test fuel pressure next time. Thanks

SonicVQ

Here is a video you might find helpful:

ZNismoZ

Thanks, perfect

Woketman

Please do not forget to report back if/when you find the issue as we are all interested in knowing. Thanks!

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ZNismoZ

Will do, thanks

ZNismoZ

Update. I bought the fuel port from z1 motorsports to check my fuel pressure. At idle, the fuel pressure is around 28 psi. So I bought a new fuel pump assembly and installed it today. The fuel pressure with the new pump assembly is around 53 psi at idle now.

The car is very responsive now during acceleration, no hesitation. I don't remember the car being this quick, even when it was new. I was never able to check fuel pressure when the no starts were happening, but I am thinking it was most likely the fuel pump.

I will report back if I have another no start during the summer. Thank you all for your help.

Tractionless

Glad you found it. I had the same problem within the last couple of years, even replaced the fuel pump motor only and it still happened. When I finally replaced the entire module is when the issue was resolved. I chalk it up to a malfunctioning fuel pressure regulator which is built into the module.

Hopefully you did a billet fuel hat at the same time.

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