2010 Nissan Pathfinder starting issues

Booka5

We have a 2010 Nissan Pathfinder, which we bought in 2016 and have had this issue since day 1. When the temperatures begin to drop to 40 or below, our pathfinder will not start. It turns over but won’t start. But, when being jumped, it will instantly start right up.

We have replaced the fuel pump, alternator, starter, relay sensor, ignition switch, the main computer thing (sorry, not a car person and don’t know the correct terminology), the battery connection cables, and the battery 3 times. No mechanic can figure it out, the Nissan dealership is clueless. When scanned, it doesn’t throw any codes but will throw a blank screen which has everyone puzzled.

I can’t, in good conscience, sell it to anyone knowing it’s totally unreliable. I have read multiple forums and I know I’m not alone with this issue.

Has ANYONE found the culprit to this annoying issue and had a successful fix to it?

PF_Flyer

The blank scanner makes me think there's no power (perhaps a fuse?) to the OBDII port. Until you get some codes, it's going to be hard to tell what might be going on

PF_Flyer

Maybe your engine compression is a bit on the low side. If you have a compression problem due to piston rings, cold weather could exacerbate the problem as pistons contract and there's not quite enough compression for cylinder(s) to fire. Has anyone run a compression check?

Booka5

But it easily starts when being jumped by another vehicle or even a jumper pack. Could low compression have anything to do with being able to be jump started?

PF_Flyer

Well since it's under 40 when you're jumping it, perhaps the jump gives you a little more vigorous crank and you get enough compression to fire up.

A semi-extreme illustration... save you DO have a compression leak. If you turn the engine over very slowly, the air/fuel mixture would simply be forced out the leak without compressing enough for combustion to take place, right? But if you turn it over faster, the mixture wouldn't have time to "get out of it's own way", compression might then be high enough for the engine to fire.

If it IS compression, and is just on that edge of being enough that the cold temps exacerbates the issue, that MIGHT explain it.

Have you noticed any mileage or power drop offs?

The whole blank scanner thing still makes me think there's an electrical or ECM issue as well

Let's see if we can loop in some of our wiser members here.. @thecardoc3 @imidazol97 any thoughts?

Booka5

I believe we replaced the ECM already. If it is an electrical issue, then what?

Sorry, I’m a female so bare with me. I’m pretty clueless about vehicles.

PF_Flyer

I'm no expert either, just trying to go through what *I* would be thinking about in the same situation. If it was some kind of electrical issue, then I would expect the temperature wouldn't matter, maybe cranking amps from the battery going a bit low in the cold, but you're only talking about 40 degrees. I wouldn't expect that to affect battery power that much. And no power to the scanner port is just preventing you from seeing if there are any trouble codes.

Need to eliminate possibilities and narrow things down. A compression test would let you know if there are any issues there. That might be where I'd start