rev hang

Hi together

i have an issue I dont like :-).

Reving in neutral the engine, the rpm keeps rising even my throttle is closing. The flywheel etc are light so I guess the engine keeps burning and ans so does induce some torque even with throttle closed - there is probably still enough air in my intake manifold which is also quite big.

Engine: BMW m50 turbo

The only way to avoid this, is running a strict fuel cut with throttle closing but I actually dont want to run an overrun fuel cut... any ideas where this phenomenom comes from? do I need to close my throttle even more?

thanks for help

What ECU are you using? Usually spark is retarded to brink an engine into idle. The ECU sees the throttle in idle position and pulls RPM down by cutting timing.

Close the throttle more... Or you may have an intake manifold leak.