Struggling to start when weather is warmer

[GT1990]

Have a 2016 Mustang GT that just hit 40k miles. Lately I noticed the warmer it is outside It's struggling to start. It happens often but not every time. I am noticing it getting worse though over the last couple weeks. Turns over for up to 3 seconds. Car seems to drive just fine. Any ideas? Fuel pump issue? Spark plugs?

Sponsored

 

[Farkel]

How old is the battery? Is it fully charged?

 

[mookieit]

Not the best answer, but here is my experience.

I had the same issue and over time it got worse. On cold starts it was fine, but then when I would go to work at 9 am and at 5 pm when leaving it would struggle to start.

I live in Tampa and it is pretty warm throughout the year.

Then I got random misfires and since I was at 100K miles, I decided to throw OEM parts at it. Changed spark plugs that were recently done 20K miles ago, coils, injectors and fuel pump, didn’t change battery.

Everything went back to normal, unfortunately I never figured out what exactly was the root cause.

I do have the old parts and planning to troubleshoot it when I get the time for learning.

 

[robvas]

How old is the battery? Is it fully charged?

If it's turning over normally it's not the battery

 

[robvas]

There are a bunch of threads related to this

https://www.mustang6g.com/forums/threads/extended-cranking-when-hot.159206/

https://www.mustang6g.com/forums/threads/warm-start-issues.80995/

https://www.mustang6g.com/forums/th...-too-long-cranking-up-before-starting.158742/

is the car stock?

Don't just start throwing parts at it. Maybe log some data so you can compare a good start and bad start.

 

[GT1990]

How old is the battery? Is it fully charged?

I got the car at 29k miles. Battery was tested end of September before making the drive from Oregon to las vegas. I'll get the battery tested today.

 

[GT1990]

There are a bunch of threads related to this

https://www.mustang6g.com/forums/threads/extended-cranking-when-hot.159206/

https://www.mustang6g.com/forums/threads/warm-start-issues.80995/

https://www.mustang6g.com/forums/th...-too-long-cranking-up-before-starting.158742/

is the car stock?

Don't just start throwing parts at it. Maybe log some data so you can compare a good start and bad start.

Car has the ford performance stage 3 power pack. And aftermarket exhaust and x pipe.

 

[GT1990]

If it's turning over normally it's not the battery

Not turning over normally

 

[ZXMustang]

Could be fuel pressure issue, could be something in the tune. Would need a pre-start log to see what the pressue is before it cranks then see where everything goes when its cranking then finally starts. Work with your tuner to start if you're tuned. If not you might need a trip to the dealer.

 

[Paddles]

Does it smell rich or reek of fuel?
I agree might want to look into that tune.

I always vote for new battery for peace of mind if current one is 3+ years old and of unknown origin in a used car.

 

[GT1990]

see

I have the stage 3 power pack I installed back in July. That comes with a basic tune just so everything functions properly. I didn't have issues with starting until about a month and a half ago.

Sponsored