Flat battery - or not....

For me the first area to check/charge/replace would be the battery.

It should read 12.6volts or more, at rest with the ignition turned off. 13.5 to 14.0 volts when the engine is running.

 

Agree with the biglad (twice in one day - people will talk)!
Battery has to be the first port of call no matter how new or what condition you think it might be in.
Also check for loose connections, poor earth, corroded contacts etc

 

, I had this problem with my tiger if I stalled it, it sometimes wouldnt start but if turned off and left a while it would fire up just fine, it was charging ok and the battery is still on her 9 months later so mine was not a batt prob

nicked this from thebiglad

I'd like to bet any money that the problem is due to the IAC valve (Idle Air Control). It is this that controls starting and idling. It works with a stepper motor and vacuum from each of the throttle bodies and is located under the airbox.

Apparently the stepper motor valve assy get dirty and sticks, so cleaning is usually all it needs. The vacuum hoses are known to perish and this affects the vacuum. To replace the hoses with triumph jobbies is not too dear but it's only vacuum hose that can be bought (and has been, by me) by the running metre.

I'm just about to do this job on my 955i as it has the same system and the same issues.

 

Sounds healthy to me.
What Crispy is saying about vacuum hoses and stepper motor cleaning sounds like a possibility

 

The main thing was the IAC valve, I guess the IAC valve if its sticking doesn't get to the required position quickly enough to allow the engine to start, if the hoses have perished i suppose they could be collapsing or split causing a faullt.
hopefully @thebiglad will be along shortly to explain all

 

I would be tempted to check the ignition switch or the wiring to it is not at fault.

 

Mine did that, if I stalled it and tried restarting it would spin but not quite fire them it wouldn't spin at all totally dead, leave it for a while and it was fine. I haven't tried lubricating it yet but I'm sure biglad will explain the reasons as he's the one who told me about it

 

When it comes to elastictrickery, which I tend to regard as something of a black art, I simply check such things as tightness of battery terminals, cleanliness and tightness of any connectors etc and the condition of the wiring itself eg no chafing or wires trapped in tight (perhaps only occasionally) places, causing a temporary short, and the condition of the insulation etc.

More than that and I start to get confused!