TLDR:
power. no crank.
it eventually (after a bunch of tries) actually did crank and start after i hit radio power button???
Should I be worried, or take it in to a mechanic?


Longer version:
2013 G37S, Manual sedan.

Car was not driven for a few days; but had been working fine.

Wednesday:
Went to start the car; Clutch-in; Start button (normal start procedure):
Power came on. But, no crank. Heard a single "clunk" like sound.
Repeated this for 3 or 4 tries.

Maybe it is the battery (doesn't seem like it, but maybe):
Put the car on the charger until it was fully charged (was at around 50%).

Did not try and start it again that day.

Thursday:
Repeat. Clutch-in. Start button. Clunk.
3 tries, and gave up; luckily we have another car, took that to dinner.

Read a few forum links, which pointed towards the immobilizer or the ESCL.

Came out with both key fobs (backup had a dead battery).
Both in the car. tried each one in the fob-hole;
No change -- power, clunk.

Put my OBD2reader into the OBD2port AND then hit the Power button for the Audio system.
(reason: audio system was searching for my phone's bluetooth ... obd2 needed phone's bluetooth (bluetooth had been disabled on the phone, up until this point as well)).

At this point, the car immediately cranked, as soon as I hit the audio system power button.
I don't think i had the START button pushed (because i was using that hand to hit the audio power button).
Don't even know if i had the clutch in.

After that; started the car 3 times. no problems.
OBD2 reports no issues.

Put a new battery into the backup fob; then came back with only that. and the car started again.
turned the audio system back on. car started again.

Sitting on the charger now to get it back to 100%.



The fact that it just started up when i hit the radio button (or jammed in the odb2 reader) is just not filling me with confidence that I won't be stranded.
There are no error codes from the OBD2 system, so I'm not sure if a mechanic would have anything to tell me. Anyone have any insight or suggestions?

Thanks.

 

Update:

Happened once again today not 5 minutes after I turned off the car to go into a shop.
Changing from bluetooth to radio did not allow for starting, but turning off the audio system power completely seemed to work.

 

Starter motor, or the clutch pedal position switch. The latter is a little plunger switch at the clutch pedal which needs to be depressed in order to start your car. i.e., your foot is on the clutch. It's like a $20 thing that you can easily DIY replace. The starter motor, well... it's a starter. DIY or shop, either way.

I've had both fail on me over the years, sounds familiar.

IDK what the radio button has to do with anything. That's weird.

 

Thanks for the insight:
re: the clutch sensor?

The car seems to be acting normal with the clutch sensing when this issue is happening: The engine is trying to start (clutch down and "start" button pressed). Normally, when the clutch is not down, the car only turns on the electronics. and also has a on-screen message to 'press the clutch to start engine'.

So, would the Clutch Position Sensor still be as a possibility in this case, since the car seems to know the clutch pedal is in the right spot for starting?
Would be great if that was something that makes sense, if it is a cheap part and an easy DIY swap.
ETA: I'm still on the original clutch. I've read about the clutch failure issues on this model. I don't think this is one of the indicators of an impending mechanical clutch failure, right?

Checking on the starter motor is a good idea. It doesn't sound like it is struggling - but if it is electrical i guess it wouldn't be struggling.
And yes. The audio system thing is very strange. I wonder if there could be something electrical; but since it has only happened twice now, and weeks apart, that also seems unlikely.
And it seems like it is related since, both times now, the solution was audio system related (though I am aware that a sample size of 2 isn't enough to be 100% certain).

 

When my clutch pedal position sensor started to fail, it would do so very inconsistently, and it's not like I knew what was going on. Sometimes it worked, sometimes it didn't. And it just got worse. I thought I was losing my mind. Replaced the little plunger switch, and all was right with the world again. Car started right up 100% of the time.

When the starter started to fail, I would intermittently get this single "clunk" or "click" noise trying to start the car. Again, sometimes it worked and sometimes it didn't. Replaced the starter (with an OEM reman), and it's been fine ever since.

Do either of these address your problem? Just sharing stuff that happened with my 6MT.

 

Stock radio?
Any aftermarket items plugged in (BT adapter, charger, etc.)?

There should be correlation/ interference between "the radio" and the engine start sequence.

This is a odd issue for sure...

 

Yes, stock radio, and stock ECU/mapping. Stock everything. I'm one of the weirdos with an unmodded G (that might change when if i need to have the clutch parts replaced).
Nothing plugged in to anything at the times where i was getting the "Clunk" with no start.