Can you check the operation of your intake flaps for me? I'd appreciate it. I'm trying to find out if mine work properly. The linkages for both flaps are clearly visible under where the flaps are and you'll see them move as the flaps open and close. One is in the center of the crossover pipe (flap 1), the other in the intake manifold itself where the crossover pipe connects (flap 2).

On my car flap 2 opens just above fast idle, probably around 1000-1500 RPM. According to some literature provided by others on this forum, it's not supposed to open until about 3300 RPM. But I already changed the controller for both flaps and the behavior is still the same and everything looks like it's hooked up correctly.

Flap 1 opens much later and I'm not too concerned about it right now. But according to the quoted literature flap 1 is supposed to open before flap 2. This is not the case on my car.

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2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL

On my car flap 2 opens just above fast idle, like yours.

Jeremy

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

Huh, interesting. Thanks for making that observation. In the Bosio thread pimpernell posted the following:

So it looks like this literature could be wrong.

__________________
2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL

The information I provided came from the Mercedes workshop dvd. It also coincides with the information given by another poster who owns a 95 e300d. I am taking a stab in the dark, but, there are two vacuum pressure switches located adjacent to the air intake filter box. They are both the exact same part.....one controls the egr valve, and the other controls the resonance flap switch. Is there any possibility that the vacuum lines may have gotten switched somewhere along the way?

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96 E300d

this information was in a prior thread, and was provided by Dr. Diesel



SUBJECT: DEALER TECHNICAL BULLETIN 04/98

04/98-3 GROUP 07 - MODEL YEAR 1996/97 E300D (210.020): In cases of slight engine surge at part load between approximately 2000 and 2400 rpm, please perform the following procedure. 1) Check for leaks in the vacuum system. 2) Check vacuum pump for proper function. 3) Check the vacuum transducers (Y31/1, Y31/2) for proper function and leaks (refer to MB-Net Message No. 83 dated February 21, 1997, DTB 04/97, Topic No. 04/97-3). 4) Check the pressure control flap and intake resonance flaps for free movement and replace as necessary. 5) Check EGR valve for free movement and replace if necessary. 6) Check the intake system for heavy carbon build up. 7) Check the injection pump timing and set to specification, if necessary. If all the above have checked OK, the engine control unit should be replaced with a new version as follows:

017 545 93 32 replaced with 025 545 69 32 for MY 96 vehicles

018 545 36 32 replaced with 025 545 70 32 for MY 97 vehicles.

Note: Replacing the ECU will not repair the condition unless the above listed procedure has been performed and all systems are operating to specification.

Dr. Diesel

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96 E300d

Have you observed your flaps? I wonder if their behavior is the same.

I replaced those 2 pressure switches next to the air filter box some time ago and I hooked them up the same way the old ones were AFAIK. The front switch's OUT line goes to the EGR, and the VAC line goes to the other pressure switch. The rear switch's OUT line goes to the EGR flap and the VAC line goes toward the vacuum pump and intake flap switch among other things.

Would anyone else care to check these lines and/or the behavior of the intake flaps?

__________________
2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL

Well, I don't want to confuse the issue, but here is what things look like on my 95 E300D. Keep in mind that I'm not entirely sure what the "OUT" line versus the "VAC" line is that you described. However, my front switch has a vac line that goes to what I believe is the front resonance flap. The rear switch has a vac line that goes to the EGR. The lines I described above connect to their respective switches on fitting that extend horizontally from the switches. The switches also have fittings that extend vertically and the vac lines from those fittings go to a central hub located between the two switches. I can take a picture of the set up if needed and would have but it was raining when I ran out to look. Hope this helps!

I hope to be able to check the flap later, I'll let you know if I do.

__________________
'95 E300D ("Tank") - 231,000 miles
'79 240D ("Biscuit") - 197,250 miles (Sold)
'83 240D ("Ding-Ding") - 217,000 miles (Death by deer)
______________________________________

"Back off, man. I’m a scientist” ~ Peter Venkman

>> But according to the quoted literature flap 1 is supposed to open before flap 2.

The quoted literature fits in with the physics of these things. Your car is definitely wrong.

On my E300D, the valve in the crossover opens first, followed by the one in the manifold proper at about 3500 rpm.

Is the rest of the vacuum system "wired" up correctly? On mine, there are quite a few restrictors and tee joints between the vacuum pump and the vacuum supply to the solenoid valves.

My setup is like yours, with the rear switch vacuum line going to the resonance flap switch. Just another guess, but is it possible that the electrical connecting plugs to each unit could be switched? I don't know if a code would be generated, but if that were the case, the vacuum switches would be sending the ccu incorrect information.

__________________
96 E300d

At what RPM does your crossover flap (flap 1) open?

__________________
2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL

Please do if you have the chance.

__________________
2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL

It doesn't appear that my electrical connections are swapped. On the pressure switches as well as the flap controller, each plug connects to the closer outlet. Ditto for the vacuum lines on the flap controller.

__________________
2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL

Bump.

__________________
2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL

As kindly posted by Pimpernell, here's what I found on my car.

The full thread is here:

EGR/Resonance Control Module

My engine is a OM606.910, naturally aspirated. To do this check, I connected LEDs to the solenoid valves which are fitted under the inlet manifold, ran the wires into the car, and watched the LEDs as I drove along.


----------------8<------------


Here's how the resonance flaps work on my car;

The valve in the crossover pipe, I'll call X/O, and the valve in the manifold itself, I'll call 3/6.

The solenoid for the X/O valve is connected to the Yellow / Brown wire pair, and is the upper of the two solenoids when in the as installed position.

The solenoid for the 3/6 valve is connected to the Grey / Brown wire pair.

In the relaxed position with no vacuum, the X/O valve is closed - i.e. the crossover pipes remain independent for their full length.

With no vacuum, the 3/6 valve is closed, and the manifold behaves as an independent pair of 3 cylinder manifolds.

<2400 rpm 3/6 valve Closed, X/O valve Closed

>2400 rpm &
<3500 rpm 3/6 valve Closed, X/O valve Open

>3500 rpm 3/6 valve Open, X/O valve Open

I didn't reliably obtain any switching above 3800 rpm as has been suggested elsewhere, but, for me, that's quite academic; it's not an area of the rev range that I use often, or for any duration.

----------------8<------------

The factory manual "Model Year 1995, Model 124.131, "Introduction Into Service" would seem to agree with you. Both flaps closed until 2550 RPM, then the crossover line flap opens. At 3350 RPM, the manifold flap also opens.

When I observe the manifold flap opening at just above idle, I am observing the car sitting in the garage, not moving. Perhaps it is different actually driving the car. It is also possible that I have a problem with the flap system. I'll go though it and see what I find. No codes are being set, BTW.

Number_Cruncher, you should really take your car out and thrash it occasionally. The 606 engine is made to spin up to 5400 RPM. Your LED monitor is clever, I may shamelessly steal the idea.

Jeremy

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970