Is this common for a M104 to lag' at first and suddent rush of power at 3500 RPM (it feels like it has a turbo ) or is my exhaust is clogged??

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Current Garage
2008 Mercedes GL320 CDI 188k mi Repair/Work in progress
1994 S350 160k mi Garage Queen & prepping for repairs
2005 E320 CDI 203k mi Healthy & Daily Driver
1994 S350 357k mi Retried as parts car
1984 300TD 214k mi Blown OM617 Poss OM603 Swap??

Sold
1987 300SDL 200K+
1994 S320 181K mi
2008 E320 Bluetec 127k mi
1999 S420 130K mi
1980 240D 360k mi
15+ Others that has come, stay and gone

GONE, BUT NOT FORGOTTEN
1995 E320 SE 220k mi
1984 300SD 350k mi

Might be when variable intake runner length valve cycles???????

M104 has a valve in the intake manifold that effects a change in the length of the intake air path. Kinda like headers except for the intake side. It's purpose is to tune the intake to match load and RPM. Maybe someone more knowledgeable can explain better................

J. M. van Swaay

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1994 E320 Wagon, 230,000 miles
1995 E320 Sedan, 106,000 miles
1994 E500 Sedan, 79,000 miles

Completely normal,,,, just sit back and enjoy.

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95 SL500 Smoke Silver, Parchment 64K
07 E350 4matic Station Wagon White 34K
02 E320 4Matic Silver/grey 80K
05 F150 Silver 44K

yeah it just feels weird... i found a wikipedia on it,

http://en.wikipedia.org/wiki/Variable_Length_Intake_Manifold

__________________
Current Garage
2008 Mercedes GL320 CDI 188k mi Repair/Work in progress
1994 S350 160k mi Garage Queen & prepping for repairs
2005 E320 CDI 203k mi Healthy & Daily Driver
1994 S350 357k mi Retried as parts car
1984 300TD 214k mi Blown OM617 Poss OM603 Swap??

Sold
1987 300SDL 200K+
1994 S320 181K mi
2008 E320 Bluetec 127k mi
1999 S420 130K mi
1980 240D 360k mi
15+ Others that has come, stay and gone

GONE, BUT NOT FORGOTTEN
1995 E320 SE 220k mi
1984 300SD 350k mi

I bet there is a sudden rush of fuel right around the same time......and a sudden rush to single digits for mpg's....

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

Your right, once i did that my gas needle when down for a few seconds and when up back...Like what any High output jeep engine dose, Suck aton of fuel and then release it back to the tank...

__________________
Current Garage
2008 Mercedes GL320 CDI 188k mi Repair/Work in progress
1994 S350 160k mi Garage Queen & prepping for repairs
2005 E320 CDI 203k mi Healthy & Daily Driver
1994 S350 357k mi Retried as parts car
1984 300TD 214k mi Blown OM617 Poss OM603 Swap??

Sold
1987 300SDL 200K+
1994 S320 181K mi
2008 E320 Bluetec 127k mi
1999 S420 130K mi
1980 240D 360k mi
15+ Others that has come, stay and gone

GONE, BUT NOT FORGOTTEN
1995 E320 SE 220k mi
1984 300SD 350k mi

So, ... where does it store this ton of fuel??

You're probably seeing the fuel slosh away from the sending unit.

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Gone to the dark side

- Jeff

That's about the point when the intake manifold flap changes position but there is no way you could call it "a sudden rush" in my experience. More likely a slight power increase. Sounds like your engine is down on power at lower RPMs.

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Roger E.

Mine all get a noticable boost around 3200rpm when the flap opens, it's significant.

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Gone to the dark side

- Jeff

The Resonance flap for runner length opens @ 3350 w/WOT...and the Cam Advance sol. advances the intake valve timing 20 degrees at 3000. So, between the two, there is a considerable torque difference.

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A Dalton

Same here with mine. Still makes me smile too.

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1985 500SL Euro w/ AMG bits 130k
1984 300SD Turbodiesel 192k
1980 240D Stick China 188k
2001 CLK55 AMG 101k
2007 S600 Biturbo 149k Overheated Project, IT'S ALIVE!!!

Well my tranny has some issues with shifting, it wont shift past 2300 unless i shift it my self....But it still have lots of for low end power though

__________________
Current Garage
2008 Mercedes GL320 CDI 188k mi Repair/Work in progress
1994 S350 160k mi Garage Queen & prepping for repairs
2005 E320 CDI 203k mi Healthy & Daily Driver
1994 S350 357k mi Retried as parts car
1984 300TD 214k mi Blown OM617 Poss OM603 Swap??

Sold
1987 300SDL 200K+
1994 S320 181K mi
2008 E320 Bluetec 127k mi
1999 S420 130K mi
1980 240D 360k mi
15+ Others that has come, stay and gone

GONE, BUT NOT FORGOTTEN
1995 E320 SE 220k mi
1984 300SD 350k mi

I'm not sure if it is a huge power boost or a mild power boost with a huge sound boost. I've noticed it as well, it just seems rather un-Mercedes-like to have such a sudden, dramatic shift in power delivery and sound when the intake flap switches over. Not that I mind.

Yeah I too notice that, at first it smoothly accelerate, but once it passes 3200 rpm it roars it's way up, as what mr.project said unmercedes like feel

__________________
Current Garage
2008 Mercedes GL320 CDI 188k mi Repair/Work in progress
1994 S350 160k mi Garage Queen & prepping for repairs
2005 E320 CDI 203k mi Healthy & Daily Driver
1994 S350 357k mi Retried as parts car
1984 300TD 214k mi Blown OM617 Poss OM603 Swap??

Sold
1987 300SDL 200K+
1994 S320 181K mi
2008 E320 Bluetec 127k mi
1999 S420 130K mi
1980 240D 360k mi
15+ Others that has come, stay and gone

GONE, BUT NOT FORGOTTEN
1995 E320 SE 220k mi
1984 300SD 350k mi

The 104 HFM/SFI is a high performance engine. So you have to expect the sport performance .
There was a design leap foward when they got rid of Distributors and went with full Electronic Sequential FI. And b/c of Full electronic management, it was easy to add cam advance, HFM metering, and SFI, along with the intake resonance system. A great achievement and quite modern for that time.

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A Dalton