BMW 330i 325i E46 DISA Valve Operation Test

How to completely test your DISA valve, also called the Intake Manifold Resonance Valve, for functionality before you decide to repair it. You will find this valve on an M54 engine in a BMW E46 3 series, an E39 5 series, or an E53 X5 3.0i.

If you want to go one step further than the whole finger over the hole test, I'll show you how to confirm the complete electrical functionality of the unit. This video will also teach you how the valve operates.

DISA is an acronym for "DIfferenzierte SAuganlage" or differentiated intake. It changes the length of the passage the air travels through inside the intake manifold. At low engine speeds you want the air to travel through a longer tube to produce torque most efficiently, and at high engine speeds you want that tube to be short. This is why your BMW engine is so torquey compared to, say, a Honda engine, which doesn't start to pick up until you rev it really high.