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Intake manifold - Tumble flaps

Old 01-30-2019, 07:23 PM
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Intake manifold - Tumble flaps

I monitor real time data of my engine operation sometimes with the icarsoft.

Sometimes I watch the switch from short to long intake runner and know how to activate the switch myself while driving. This isn't a problem.

The tumble flaps are another story.
The swirl/tumble flaps are monitored by sensors at the back of the engine and give off a voltage reading to icarsoft.

At rest with no vacuum applied to valve, the tumble flaps are not activated and the voltage reading is approx 5 volts.
When vacuum is applied to the value, the tumble flaps are activated and move into the intake runners. Voltage reading is almost 0 volts.

The problem is, I almost never see the tumble flaps activated. I've see them activated on cold start for about 30 seconds and when closing the throttle from high rpm at times. I've come across a chart which shows when they should/shouldn't be activated, but the chart and how mine are working don't match. Also, I don't have any engine codes being thrown.

Does anyone have any further information on when the flaps are active/not active ? The engine is a M273.
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Old 03-01-2019, 11:05 PM
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2010 W212 E550 4matic
Just stumbled upon this thread. Might be a redundant question, but were you moving when monitoring the tumble flaps? From what I've been reading they activate the long runner for low rpms and short runner for WOT. There's probably other parameters that have to be just right for these flaps to change position. In what menu did you find them on your scanner tool? I'm guessing it should be in the ECU section, but my Autel has a weird layout and I don' think I've ever come across them.
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