1981 E24

alpina

If out for a long drive, say car has been driving for an hour or two, once engine is turned off have to leave for about 10/15 min before will start again.
Sounds as if starved of petrol, an immobiliser like precaution but no immobiliser fitted(as far as I know) besides this nothing at all wrong car goes Limerick-Dublin & back no issue & runs excellent, have had 3 yrs now, not an issue really for the amt. of use it gets, just curious incase anyone has experienced such, cheers..

peasant

Had similar issues on my old R4, great difficulty re-starting when the engine was hot.

Basically the residual heat from the hot engine heated the carburettor area to such a point that most of the fuel evaporated before it got into the carburettor. (You could smell that, though)

Had the carburettor worked over (re-sealed) and the fuel line connections re-done ...that solved it.

mike65

Check valve in fuel line failing? Most likely to be obvious when hot.

Mike.

carchaeologist

An E24 is surely a BMW, i reckon anyway....an alpina one maybe...fuel evaporation sounds likely alright,especially if it runs again when cooled.

Daxklynsmith

The E24 is fuel injected, and if you dont have vacuum, will not start, when you're stopped the extra heat from the engine is expanding something in your fuel set up (if it's turning over and not starting) until it cools down again.
Check your fuel lines are'nt becoming perished, when running,you may be getting enough fuel through to keep going with higher than previous fuel consumption but sucking air when you've got heat around.
There's a spare 80/81 E24 sitting next to my house if you are interested pm me.
My South African E9 2800 CS did it to me on my last holiday run, outside temp at 30 degrees plus, would not start for a loooong time

Esel

Pedal to the floor usually works in this 'hot car won't start' scenario.