Hi G-Gang!
I just inherited an 2008 with 60k miles from my aunt. Except for the normal wear on drives seat, it's in showroom condition. Feeling lucky, except for this issue.
For sometime I've noticed that at various times it will have an extended crank before it fires up. It really feels like a fuel bleed down, as it will fire normally right after you shut it off. When the extended crank happens it feels like the engine is turning over faster than a normal start, again, leading me to think there's no fuel being compressed. It's also pretty random, I cant seem to corollate it with outside temperature or temperature of the engine. Sometimes it will fire perfectly in the morning, sometimes the extended crank happens. It happens more ofter if the car has been shutoff for more than 1 hour.

I've replace the fuel pump with a factory one, but no change. All new factory crank and cam sensors as well. (thought I'd just do it as there are enough stories out there that they're not that reliable).
It does always starts... no codes active or pending. Looking for other areas to focus on.
Here is what it sounds like, might have to turn up the volume. https://photos.app.goo.gl/eYeGRchVgcLxPDe2A

Thanks for your input!

 

That's not so bad. My (V35) long crank was way worse than that. Mine was the check valve in the fuel pump assembly but you already swapped that. Hard to see because the tip of the needle is off the screen but looks like your tach is registering rpm during the long crank so probably not the crank sensor and you changed that too. If an injector(s) leaked into the cylinder rather than the fuel pump letting the fuel drain back to the tank, you may still have low rail pressure. You can try and prime the rail by going key on engine off once then shut off. Then push to start. If the car always starts normally after extra priming of the rail like that, you might look into checking the fuel pressure to confirm if it's leaking down. But an extra fuel pump prime cycle is a free and easy way to test the idea.

 

Read my thread before you replace unnecessary parts
Long cranking times

 

i've been having this long crank condition myself for probably 2 years now. never happens overnight, but it's pretty severe 1.5-2hrs after the car had been shut off (i feel like it's heat soak related). fuel pump had been replaced along with the crank and cam sensors. my hunch it's starter related, but i don't feel like throwing more parts at it. read MaLPoPieS thread - his resolution was to put in the OEM (Denso) cam sensors.
keep us posted if you figure it out.

 

Was able to borrow a scanner and did some realtime monitoring. It's appearing to be something with the crankshaft sensor or at least what that circuit is reporting, as you can see what the monitor picked up on a good start vs what it's seeing on a bad start.
During an extended crank start the rpm's were being reported as being slower and even goes down 100rpm before going back up and engine firing. In reality, the extended crank is as fast or faster than a normal start and never actually slows down while its happening.
Crank sensor is a brand new Denso and the extended crank is exactly like it was with the original. Going to look at the manual for more ideas on what to look at next.


Good Start



Bad Start - Extended Crank

 

nice to see you're busting out some heavy artillery here (i.e., logging this)!

 

I assume you did not read my entire thread about this. If the cam and crank sensors are not in sync, the ECM will default to basic start after a extended period of time. Mine was 3-4 seconds after shutting it off hot or cold. After i reinstalled my OEM Denso, true Denso not chinese clone from autozone or advance, the engine now starts and restarts hot or cold within a second.
I did what you did, log, read, scan, read, and got nowhere for weeks. So read my thread and make sure you use ONLY genuine Denso sensors on the HR as it doesn't like anything else.. at least mine doesn't..
Also, make sure your ignition coil power transistors are good, otherwise, that will contribute to ignition timing issues, it did on mine as i had 2 good coils with bad transistors and the spark was off and that was throwing one of the exhaust cam timers off.. Post #16 in my thread you can see the video on the Bank 1 cam phaser going bezerk with bad coil transistors.

 

just to bump this up. i think i may have found my culprit of extended cranks when engine is warm (after letting it sit a few hours). pretty sure i have a leaky injector(s). if i hit the gas pedal and try to start it, it cranks up normally. it never does this in the morning, ever. only happens after a drive and letting it sit anywhere from 30mins - to a few hrs. give it a try on yours. i will swap the injectors and post an update.

 

I did what you're thinking of doing and it didn't work in my case. I bought a set of NEW OEM injectors and when i took out my originals out, they looked surprisingly clean at the tip and the filters had no debris in them. I went and installed the new ones as they were New Old Stock with no returns and same issue. I had that thought of a leaky injector(s) after engine shutdown and fuel still coming out onto the plug causing fuel flooding but that's 1980s stuff with TBI systems, not with the HR engines IMO..
What i also noticed that if you replace the fuel module with ANYTHING other than OEM, it will fail sooner than expected and cause fuel aeration/leak inside/pressure loss due to cheap o-rings that swell up and break. And the cross over tube also fails to suck fuel from other side due to the cheap non-fuel resistant o-rings from china. I know because i did that also and after few days, i quickly went back to my 17 year old OEM fuel module and no issues so far.

 

all i can say is, it starts right up if i hold the gas pedal without extended cranks, meaning it has fuel in it somehow. i wish the infiniti "engineers" allowed for an easy fuel gauge hookup, but alas...

 

This is what i bought to hook upto the fuel line: S&G Tool Aid 58625 Fuel Rail Adapter VQ35HR
Then rented out a fuel gauge from AutoZone and that's how i got my fuel pressures tested.
I also held the gas pedal down all the way hoping it would start up faster but that made no difference. It all came down to those 5 sensors; 1 crank, 4 cams..

Last resort would be the ECM going out on retirement, if all was checked and makes sense. You can get Consult 3+ for free and use any windows laptop to reprogram a replacement ECM from another car using a $200 VCI adapter from eBay.

 

well, looks like a different set of injectors solved my extended cranks after sitting a short time (warm engine) condition (going on 2-3 years). first set of reman injectors from ebay were doing the same thing (talk about going crazy) - the car would crank excessively and start with gas pedal to the floor (clear flood mdoe) - indicating fuel in the cylinders. i decided to send my old ones to get remaned, but those ended up leaking even worse. at this point, it takes me less than an hour to swap these bad boys lol ended up grabbing a set from a local junk yard that appeared to be in decent shape.
quick test to see if it is the injectors, is to hold the gas pedal to the floor and seeing if the car starts. if it does, it's your injectors leaking.