Hi Guys,

Had my 2004 RR 4.4 Autobiog with BMW V8 for just over a year now, however recently when the engine is warm (say driving for over half hour) then the car is left for an hour or so, when restarting it will take about twice/three times as long turning over before it starts. If I press the throttle slightly this will make it splutter a little and catch quicker in this situation so presuming fuel related - I have used my old carsoft diagnostics (for BMW but seems to work with this engine) and no faults found - I'm a little lost so any advice much appreciated! 2004 4.4 Autobiography - gone
2014 4.4 SDV8 VSE - gone
2012 4.4 TDV8 Overfinch

A few things it could be, depending how good a scanner you have used ie isolating engine electronics etc but on the modded cars we work on, fuel line getting hot and fuel evaporating, fuel filter, petrol tank breather (if you take the cap off you will get a whooosh as the air is sucked in. Before looking at stuff like this I would get a proper diagnostic done. One day your life will flash before your eyes......................................make sure yours is worth watching!

Trouble starting when warm is quite often a crank position sensor failing.

Diagnostics should have thrown that up One day your life will flash before your eyes......................................make sure yours is worth watching!

A good diagnostics would pick it up but there is no guarantee anything is being stored .... I would not rule it out.

Thats the prob when you have an intermittent fault, you can bet it wont do it when you need it to. One day your life will flash before your eyes......................................make sure yours is worth watching!

I guess there's no harm in changing the crank position sensor, have been reading this morning and seems others have similar issues with this being the cause, any idea of cost of the sensor and how hard to fit?

Appreciate everyone's input so far. 2004 4.4 Autobiography - gone
2014 4.4 SDV8 VSE - gone
2012 4.4 TDV8 Overfinch

From what I have heard they are pretty cheap and normally easy to fit.

With mine it was linked to dirty fuel system. I replaced the pumps, filter, cleaned the lines, tank and injectors as well as the inlet manifold.

I suggest to start with injector cleaner in the petrol and using a clean petrol (V-power or the likes) for a bit and see if that makes a difference after a while. MY 2010 5.0 SC Galway green and sand interior!!
Have the Faultmate MSV2 Extreme to be tinkering with the settings etc. !!

i have the exact same problem with mine even down to the fact if i press the gas pedal it splutters the same and starts, i have the faultmate system and no fault codes are stored?

Matt

Good to hear I'm not alone lol - I am going to try using premium fuel for a few tanks with some fuel system treatment and see if that helps - does yours do mostly short trips too? 2004 4.4 Autobiography - gone
2014 4.4 SDV8 VSE - gone
2012 4.4 TDV8 Overfinch

All my trips are short and in very high operating temperatures with low quality fuel (likely diluted with all kinds of crap to make more money). Also the car didn't move for 2 years after being imported into Nigeria so silicone deposits may have played a role as well. MY 2010 5.0 SC Galway green and sand interior!!
Have the Faultmate MSV2 Extreme to be tinkering with the settings etc. !!

i have already tried all the expensive fuels and additives and it did nothing to solve the problem, i experience the problem more when the weather is warm in winter i hardly notice the starting issue??

Matt

Not on a full fat, but I had a leaking injector once which caused poor starting and eventually the cylinder stopped firing altogether

Only ever happened when warm, I guess when left for a couple of hours the fuel which had leaked into the cylinder all evaporated

Doesn't sound exactly like your issue, but something to consider.... 2007 Zermatt Silver TDV8 Vogue SE - now sold but was a great car!

I had the same problem on my X5

It was the crank position sensor