Gents,

I want to share.......
I do not own M272, but since member Tesna here has one and I been studying about it, but I never get to touch or play with the real product, it took me days to realize how
it actually works. This write up will help you guys troubleshoot your M272 Intake Manifold.

I discovered how misleading is the component name used in the DTC description by the ECM ME9.7.
The WIS and the Xentry Test and Actuation feature uses different component name too.

Many surprises when you read on......


The WIS will call this entire unit as RESONANCE Intake Manifold. Good thing they keep the INTAKE MANIFOLD in the description.




A kind of M272 introduction booklet simply call it INTAKE MANIFOLD. I am attaching the booklet.
But here is the good part on its duty or capability....



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Here is the "good" part
When you get DTC from this Intake Manifold, most common one is : CHARGE MOVEMENT FLAP ERROR or MALFUNCTION


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What a joke , the DTC editor loves to confuse people.
The problem is from the broken linkage of the Y22/9 which is the SWIRL FLAP




Do take note that there are 2 component controlling air movement or air charge movement.
Y22/9 group for Swirl Flap
Y22/6 for Variable Intake runner, short/long air path

I find this DTC description as CHARGE MOVEMENT FLAP is simply a lazy azz and if there is no obvious broken mechanical link visible,
you will wonder which one of the 2 capabilities of the Intake Manifold is having this malfunction ?


This is Xentry description of the test for these 2 capabilities of the intake manifold :


If without the Y22/6 and Y22/9 header of the title, you will be wondering what is Tumble Flap, which one of the 2 deserves to be called a Tumble Flap ?
If you are on a 3rd party scanner and no EPC/WIS and no google/MB related forums to assist , you may waste hours trying to figure out what is what ?

So the Y22/9 has now 3 names : CHARGE MOVEMENT FLAP, SWIRL FLAP and TUMBLE FLAP ...lol
Poor soul Y22/6 variable intake runner has no special name.


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Now the technical bits....

Y22/9 Swirl Flap/Charge Movement Flap/Tumble Flap is detectable by ECM when and if it does not move into proper position when actuated by ECM, because it has 2 hall/position sensors at the azz.



A is the magnet at swirl flap rod, B is the hall sensor. From iRepair Autos - Youtube





These are the flaps for the SWIRL action. OFF is open and ON is blades/flaps in action.


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The desired SWIRL effect




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You then decided to test the Swirl Flap Y22/9 using actuation feature of your scanner/Xentry.
Boooo..... actuation is not possible for Y22/9, only available for Y22/6 This is nonsense. Its only a 12V signal to send out. Usually solenoid uses 12V and not 5V.




How about the TEST feature for Y22/9 ?


TEST is not always ACTUATION, it can be physical measurement of the signal using DMM.
They want you to measure the voltage ...LOL


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At the least the Y22/6 Variable Intake Runner ( short-long air path ) can be tested using ACTUATION.



Can we inject 12V for Y22/9 Swirl Flap to test ?
Well you can if you want, but remove the connector to it and don't allow the ECM to get the 12V injection. The power to it must be fused at 1 amp for safety.




So how does the Y22/6 Variable Intake Runner the short-long air path works ?
Its like a road detour, that's all.



This are the flaps responsible for the air path detour. From iRepair Autos in utube



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Now something also very interesting here...............
There is no information on the WIS on how the vacuum actuators plumbing/routing is for Y22/9 or Y22/6.
You only get below from EPC and not WIS




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You have to decode components not named in this page to try to understand the vacuum air flow.




At a glance looking at the EPC for hoses... we will think that the vacuum pump at the Bank 2 ( LEFT ) rear azz is the one powering all the vacuum needs of
the Intake Manifold 3 vacuum actuators 22/6 2 pcs and 22/9 1 piece....WRONG !!!!!






At a glance it looks like.................





Well, we need to look more carefully......




---WILL CONTINUE-----

 

Thank you Master Surya for this very interesting study!


In depth research of mixed vacuum + electrical + mechanical + EPC + WIS + YT... it is MS! grade.


Our M276 evolution features a plastic intake plenum with similar functions with short/long runners and vacuum actuators. Complete with its built-in oil catch-can up front for overflow.
There's even a blow out cover on the top side.

It was interesting to see how ECU tracks the flap positioning to know when faults are ready for service.

Speaking of hands on service, I am due to remove my intake soon for fresh CPS :
- exercice flaps for smoothness
- empty oil out diaphragm actuators
- empty oil out if intake + front can.
(Last time I was in there I recall lubing one of the actuator shafts).

 

Thanks Cali for the M276 3.5NA information.

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Lets continue with M272 Intake Manifold.

The 3 vacuum actuators 22/6 ( 2 units ) and 22/9 are SELF-POWERED for its vacuum source, directly from the intake manifold itself, which in a non turbo engine is always below atmospheric pressure, aka vacuum.

The green arrow, what an ugly fitting style used for penetration of the hose into the intake manifold body. Why not place a good bulkhead adapter like red one ?


The green arrow ( Y22/6 or 22/6 ) hose continuation inside the intake manifold.


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So, what are the two vacuum hoses out of the intake manifold for ?
The intake manifold also is a vacuum power source for Secondary Air Injection vacuum actuator needs, thru that Y32 solenoid which is a simple OPEN-CLOSE valve.
B28 is Manifold Absolute Pressure sensor.


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So what does the mechanical vacuum pump at the Bank 2 ( LEFT BANK ) azz does then ?
It is a back up and working in parallel with Intake Manifold, to provide vacuum source for Y32 solenoid for Seconday Air Injection system
That is why you see item 20, two of them, which they are CHECK VALVES or One-Way valve.



Green lane is suction/vacuum provided by mechanical vacuum pump
Red lane is suction/vacuum provided by the intake manifold.

If say the check valve of the red lane ( intake manifold ) failed in open state, what will happen ?
Well, if that happens, the vacuum pump ( green lane ) will then suck air out of the intake manifold and send it back to engine crankcase.
Vacuum pump is always more powerful vacuum wise than intake manifold, it can achieve easy -14 PSI ( near 29 inch Hg vacuum ) for a healthy unit if brake booster not being used ( brake pedal not pushed ).
Intake manifold at best is -12 PSI ( 25 inch Hg vacuum ) during deceleration, usually 16-22 inch Hg vacuum at idle.

What happen if the check valve at the green lane ( vacuum pump ) failed in open state ?
Well, if vacuum pump is still healthy there will be suction tug-of-war between intake manifold and vacuum pump which in most cases intake manifold will loose.
If the vacuum pump small port, the membrane inside it which acts as check-valve and oil stopper too...is torn, the intake manifold would likely win the suction war and will get
lots of engine oil from the vacuum pump small size port. You will then be confused and start blaming the PCV system for the too much oil into intake manifold.
Since M272 is a MAF engine, it is bad if any un-metered air from a vacuum pump entering the intake manifold....its going to be like a small vacuum leak.




---- Will continue---------

 

The hoses type used in M272 vacuum system is a mess.
Unique bent/curve rubber hoses, mix with hard plastic pipe, adapter for size change....yada yada... so NOT elegant.

From vacuum pump to Y32 solenoid ( air pump switchover valve )




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Allrighty, happy troubleshooting for those with M272........