Starting odd behavior

[Whacko]

I was wondering if anyone else experienced this. My Z3 M Coupe parked for about two weeks. This morning when I wanted to start her the engine just cranked and she wouldn't start. Then I thought I'll crank her till the battery is dead. After a while of cranking I could sense there was something happening, and she started firing weakly until eventually she started very rough. After a few revs the motor smoothed out and she idled ok. Then I switched off and started her again with no problem. Could this be VANOS related?

 

[akash]

sound like the battery to me

 

[msm]

sound like the battery to me

+1

 

[Whacko]

Battery is very strong, indicator is green and the battery cranks that motor like its a hybrid want to take off. I don't think it's the battery but I've been wrong before..:idea:

 

[frikkieh]

From my 323i e46, I can tell the VANOS was caput, and it never showed the behaviour you described.

 

[netercol]

most prolly fuel related..

sounds like fuel pressure was slow to get up to required pressure for whatever reason.. regulator, fuelpump, ect..

 

[zaleonardz]

+1 on fuel related.

 

[Raybimmer]

If the motor was cranking then the battery was working .IMHO if it was ignition e.g. a spark plug or coil the car would not idle properly later , I suspect fuel taking long to get to injectors . Either pressure low like fuel pump on its way out or fuel filter had dirt in . Fuel pressure was not held in the fuel rail most likely and took time to build up . Have fuel pump pressure tested , also if fuel rail pressure drops over a time . Good luck

 

[rick540]

There is a phenomenon of modern fuels I have seen and that is if you start the car for say 30 sec just to park it in a garage and dont warm it up, one strugles to start it next time. the plugs get coated with a conductive layer of carbon.

I normally warm the engine up always before shutting it off.

 

[Whacko]

Thanks for the input to everyone, the problem has disappeared so I guess I'll have to wait till it gets worse - Murphy's rule