Car made a 800km round trip without incident and now wont start

infiniti
g37

#1

Hey guys,

History: My 2008 Infiniti G37s had been having a few rough starts where extra air (press pedal) was needed to get it going on cold days. This had happened maybe 4 or 5 times over the past winter and never before that. The weather has warmed up now and I hadn’t experienced any signs of that issue for about a month.

Trip: I started the car, drove it approximately 400km, car sat two nights, drove 400km home. My parking spot was taken, so I parked a few spots down. Next morning I started the car and moved it 40 feet to my spot, and left it for the day. The following morning I went to start it for work and the rough start condition occurred, but this time it wasn’t solved by pressing the accelerator…

Now: It has been a week and the car cranks but does not start. I have pulled out the back seat to check the fuel pump, and it is working fine, I replaced air filters (just to be safe), and cleaned throttle bodies. I pulled the plugs to take a look and 3 out of 6 plugs were wet, but I am partially dismissing this since I was likely slower getting to the 3 dry plugs. But if you think it is significant, the 3 wet plugs were all on the same bank. I cleaned the plugs of deposits with degreaser and a brass brush and put them back in. Tried starting again and no luck. Ran a program to check for codes, and none found, but this is typical if the car wont start I was told. The battery has run down a few times and had to be disconnected to be charged – car is now likely in learning mode again. When installed and tested on car it shows 11.68v. I purchased starting fluid and introduced a shot yesterday evening, first shot did nothing, second shot started the car… car ran very rough (almost like missing on 3 cylinders - maybe wet plugs were not a coincidence). Ordered new plugs, they will be here tomorrow, this could be the cause of the rough idle, but likely not the failure to start. I have checked all fuses related to fuel pump/injectors/ignition and all are fine.

Any thoughts on my initial no start problem? Fuel pressure regulator or cam/crank sensor? Thanks for the help guys, I appreciate it.


#2

Did the car stay running on its own, after that, or did it just stall out a few seconds later?


#3

I kept on and off the pedal to keep it running, and even stopped that for about 5 seconds and it did keep running, but it ran so rough that it had me concerned it would die and that that would be worse than simply shutting it off myself. I was also concerned that continued running would cause issues, so I shut it off after approx. 30 seconds.


#4

No mention has been made of this car’s Check Engine Light.
Is there anything that we should know regarding that topic?


#5

"Ran a program to check for codes, and none found, but this is typical if the car wont start I was told. "
CSA


#6

No CEL present, I was just hoping maybe I would be able to find a code that the car wasn’t showing yet due to the non-start. But I was told that apparently if the car isn’t running, no codes can be found. Only CEL to ever come on while owning the car was for a faulty O2 sensor about 3 years ago.


#7

It should show 12.7v. Put in a new battery, and go from there.


#8

Will try that tomorrow insightful, I had command start/remote start/car starter whatever you would like to call it installed years ago, but it never worked well being that my car was a manual. The parasitic drain was insane, and would case a battery to go stone dead in 2 weeks of no driving, so i began trickle charging a long time ago to keep the battery fresh… clearly it’s not anymore and does need a swap, so I will pick up an AGM battery tomorrow.


#9

New battery and remove the remote start and that could solve your problems.


#10

Remote start was removed yesterday morning, and no this was not the cause of the problem, however I was concerned that with the car incapacitated that I may be compounding the problem by removing it at this time. Functionality of the car has not been negatively effected as far as i can tell by the removal, but I obviously cant say for sure. I personally performed the removal and can guarantee all wires were properly removed and the the junctions covered.


#11

No arcing was detected while removing to indicate any possible shorts.


#12

I will update tomorrow after battery and hopefully spark plugs.


#13

I think you need to do a basic test for spark. Could be a coil gone bad, crank sensor, or even timing belt. Wet plugs and you said pump works so that indicates fuel is getting to the plugs. Pressing the pedal down introduces more fuel not air though unless it is all the way down that shuts the injectors off to clear a flooded condition. Rough running can also be weak spark.


#14

Bing, the part about the accelerator adding fuel to the mix while starting was my contention as well, but the mechanic I spoke to told me that this was not the case while starting an EFI vehicle, and that the ECU monitors fuel output, so pedal movement only contributes excess air to lean out the mixture. Was he mistaken, or maybe uninformed?

As in a basic test, do you suggest pulling each plug individually and turning it over once for each to test if one is not sparking?

I wouldn’t expect a coil to be my issue since the car should still start if 5 out of 6 were still sparking. A cam sensor seemed to make sense since it was an entire bank that was wet, and I honestly don’t know how the crank sensor works - i understand what it senses, but not what it does with that information.

The car runs a timing chain, and not a belt, and as far as I know they rarely cause an issue, plus I assume the noise from one breaking would be quite recognizable.