Intermittent no start issue

[xckyle]

I have a 2017 3.5 QX60 that developed an intermittent no start issue this winter.

It will crank just fine, but it will not start sometimes. Other times it starts right up no issues at all. So far I have replaced the original battery as I thought potentially it may have been low voltage causing the issue, but since then it has happened one more time.
The funny thing is that when it starts just cranking and not starting if you put your foot on the gas pedal, it will instantly start at that time, if not it will eventually time out and stop cranking.

I have Hp Tuners that I have used with other vehicles, so I did some trend scanning and I can see that I have adequate fuel pressure as well as throttle position, and that the vehicle is cranking at approximately 400 RPM with the starter.

One thing I am curious about when reading is the ECM controlled alternator, but it seems conflicting if this vehicle has it. I see it in the 2015 schematics, but not in the 2016 schematics. I have yet to find the 2017 schematics, so my thought is, it is the same as 2016? But what is happening does seem to me that it is not charging the battery properly between short trips.

Any ideas on what to go for next?

[VStar650CL]

The '16's and '17's are identical, there's no smart charging. You won't find a '17 FSM because they're HTML from '17 up. You need to rent access online, there are no PDF's.

When giving the engine extra air starts it, the culprit is usually a sticky Throttle Body obstructed with carbon in the closed position.

[xckyle]

Thanks for the info.

I did clean the throttle body, maf sensor, and change the air filter as well.

The throttle body wasn’t too dirty. I was afraid to unplug remove and force the valve open because I read online that it requires a dealership to recalibrate. I am not sure the truth to this though? Is it advised to completely disconnect remove and thoroughly open and clean the valve?

[VStar650CL]

You need to clean off the bottom lip of the butterfly, that's usually where trouble accumulates. I use a toothbrush full of intake cleaner to get behind the lip so the plate doesn't need to be forced full open. You should perform an IAVL (idle Air Volume Learn) after doing it (that should be performed periodically anyway, MAF's drift electrically over time). Since your QX60 has a CVT, the simplest tool for DIYing that is a download of the CVTz50 app along with a compatible OBD dongle like a VeePeak VP11. Although the app is for tran-smissions, it also has great engine work support, including IAVL.

[xckyle]

Thanks I’ll give that a try. Appreciate the help