My wife went to take our G35 to the store this afternoon and it wouldn't start. It would turn over, but not start. I had to pump the gas petal a bit and it started right up, but ran rough for a few seconds and smoked a good amount. I also noticed a smell, although I don't know how to explain the smell exactly. It seems to be running fine now. Any thoughts on what this could be? It has been cold lately, but it was in the garage.

 

Pumped the petal before you cranked it? If so, that doesn't do any good because the car is fuel injected (pumping only affected if carburated).

WORST case scenario (and I hope it isn't)........is possible busted head gasket since you said that it finally started up and smoked and ran rough with a smell........what smell and color smoke you didn't state.

If there was coolant in the cylinder, it would have been difficult to start. Once it fired up, it would have had to burn off all the fluid in there which would have made it run rough with smoke in exhaust (usually white smoke with a sweet smell). Once all that gunk it burnt, then it would smooth out a bit.

Just my 2 cents.

Let it sit over night and start it up again tomorrow and have someone check the tail pipe and go from there. Could just be dirty injectors. Wouldn't hurt to add some injector cleaner and see if it helps. Buy the good stuff, your car deserves it. Good Luck.

 

I pumped the pedal as I cranked it. It started right after I started pumping the pedal. I don't think the smoke had a color per se. The smell wasn't sweet. Car has started and ran fine since.

 

If it happened after sitting for sometime it can be Fuel pump...

If it happened after running for sometime, crank sensor related...

 

+1 on fuel pump..

 

I had this same issue this morning. I also had to pump the gas pedal to get it to finally start and it did smoke (white + sweet smell) a bit. Seems to be running OK now.

Conditions: Didn't run the car all weekend and temperatures we in the 40s to 50s.

Anyone have a definitive answer?

 

Not knowing your situation exactly, I would guess

1) your battery might need replacing soon, hence the cranking without starting. Eventually, it will not even crank.

2) I would attribute the smoke and smell to you pumping the pedal and flooding the engine...