Recently started having problems starting my G. I turn the ignition cranks a few times and it finally starts. There are times that it will start right way, but most of the time it will take a few cranks until it finally fires up.

About to purchase a crank sensor, but would hate to buy one and still have the same problem. Anyway to test the current one?

Should I buy direct from the dealer or go aftermarket ?

Thanks!

 

battery?

 

No, can't be the battery. Doesn't crank up slowly, it's a fast crank.

 

Highly doubt its crank sensor. That throws a p0335 code and will have erradic idle.

How new is the battery?

Look at cam phase sensors if you are sure battery is good.

 

Unplug the cam sensors and check the connectors for oil residue inside of them.

 

Also a weak fuel pump can cause this. Check fuel pressure at the engine. There's a couple ways to check line pressure.

 

Maybe it is a fuel problem, I notice when it finally starts it struggles to stay on for the first few seconds, doesn't turn off though. This has been happening once in a while.
How do you go about checking the fuel lines?
This is probably the first real problem that I've encountered in my 4 years of ownership. Great car so far.

 

Well, that's gonna have to be answered by someone that has more knowledge of this fuel system. Normally there is a schraeder valve in line with the fuel system to check pressures. If there is one (I looked and couldn't locate one), you can connect a fuel pressure tester (check local auto parts store) to that valve. It helps to connect the tool and start the car. You can watch the fuel pressure on the gauge. Then shut it down and watch to see if the pressure falls off. It shouldn't fall off significantly. If it does, most likely the pump is not holding pressure and requires replacement.

 

Its funny because I had this same problem yesterday too. For me I have never had this happen before at least not in my G but the only thing that I can think of why cars do this is because its cold outside but it was warm outside around 20 and some reason it didn't start but it was fine after i stopped it to ru some errands then tried cranking it on again.

 

How many miles are on the car and have you changed the spark plugs?

If it's fuel issue, they tend to run crappy once started and throw lean codes turning the SES light on as well

 

Not true. If the fuel pump is beginning to fail, these very symptoms appear. Once it builds pressure enough to start, it runs fine.

 

Well in that case i would suggest hooking a small gauge up to the fuel line and checking to see if pressure builds when you turn the key to ON. Prob is i do not know if there is a place to hook one up on the G35. They sell little gauges for $20 you can connect up. I'd check this before committing to a faulty pump. Could also be a clogging fuel filter.

Why i asked how many miles are on the OP's car to determine potential causes

 

I gotcha. That's the same path I pointed him to. Where is the fuel filter on the G?

 

I'm going to bet that you have a cam position sensor going out. P0340 or P0345.

 

It's not really a filter per se, more of a mesh screen under the rear seats in the gas tank.