Should a BMW engine cut out when you remove the oil cap?

[dabofoppo]

Hi Just wondering about this i was discussing it with my dad as im looking at buying an E36 328i and he said it should I have never heard of this and he said if it didnt then it meant there was something wrong. So should it? and if it doesnt what does it mean?

Thanks

[Guibo]

I am guessing there is some sort of device that can sense improper pressure in the valvetrain area which might suggest to the owner he should stop before he's deposited multiple liters of black goop on the underside of his hood (or worse yet, on the road). Seem to recall that similar devices will render some cars inoperable or otherwise very rough-idling when a gas cap is improperly tightened.

[PoleDriver]

My old E21 323i did the same, I was lead to believe it was to do with the pressure drop but never knew if it was:-
a) A fault.
b) A design feature to stop oil loss.
c) Just 'one of those things'.

[Robatr0n]

By removing the cap, you're essentially causing a huge vacuum leak which will make the car stall or idle rough.

[Big Rod]

Robatr0n said:

By removing the cap, you're essentially causing a huge vacuum leak which will make the car stall or idle rough.

^This. Lots of unmetered air entering the combustion chamber.

[buggalugs]

^^ Yup, air comes in through the oil cap, through the crankcase vent pipes back into the intake trunking downstream of the airflow sensor - engine then goes lean and stalls. If you remove it slow enough it might get chance to compensate and keep running if it's hot enough to be running in closed loop