2016 AWD Rogue struggles to start sometimes

[darrylwmiller]

I have a 2016 AWD SV Nissan Rogue that is running great, regular maintenance and a new battery I threw in last year. Once in a while when I sart the car it struggles and keeps cranking but will eventually start up. What should I be looking at before it becomes an issue to the point it does not start? CVTz50 shows 13.9V from battery while driving, and I recently replaced the battery so I don't think that could be the issue. 99% of the time when I start the car it runs right away. It is just the odd time where it seems like the starter is struggling.

Current mileage is 191,000Kms, spark plugs replaced at 100,000kms with OEM plugs. Tune up done at 100,000kms with throttle body cleaned and relearn process. Oil changed every 10,000kms. Just changed engine air filter, drained and filled transmission fluid twice using OEM NS3 fluid.

[VStar650CL]

Long cranks on Nissan engines are usually from a dying crankshaft (CKP) or camshaft (CMP) sensor. On a QR there's no good way to diagnose which one unless the culprit flatlines and gives you a P0335 or P0340. It's very common for them to misbehave by causing mystery stalling and long cranks without throwing any codes.

[darrylwmiller]

Are these sensors difficult to get to?

[VStar650CL]

The CMP is easy (in the valve cover), the CKP isn't (back of the engine above the right axle halfshaft).

[darrylwmiller]

Yikes. I see what you mean about the CKP location. Hopefully if something is wrong it ends up being the CMP. Then again, from what I read if one fails you should replace both?

[VStar650CL]

That's true on QR's for a reason that's a little weird. For reasons known only to some grody programmer in Hitachi's basement, the QR firmware pretty regularly gets confused about which sensor is malfunctioning and blames the cam for the crank or the crank for the cam. So you can't necessarily trust the codes that come out of a QR ECM. Nevertheless, unless one of the sensors is obviously flatlined, I always recommend trying a cam first in a no-codes situation. That's simply because it's easy and a CKP isn't. Then if the problem doesn't disappear, change the CKP.

The position of the CKP is very awkward, but once you get the connector popped (which admittedly can be an adventure), the retainer screw will rarely stick and will usually spin out and back in with finger torque. You can get at the screw by feel with either a 1/4 drive ratchet and deep socket in front of the halfshaft, or a 3/8 ratchet with a 6~8" extension behind the halfshaft (depending on your socket depth). With the right tools, it's not nearly as nasty as it looks.

[darrylwmiller]

You have helped me numerous times now. Is there someway I can pay you for your support?

[VStar650CL]

Nah. Long story, but this just paying it forward for me. Knowledge never dies when you do that. Pass it along.

[darrylwmiller]

Nah. Long story, but this just paying it forward for me. Knowledge never dies when you do that. Pass it along.