E300 resonance flaps, vacuum trasducers, and lower control arm bushings - PeachParts Mercedes-Benz Forum

slowmoe · #1 04-13-2004, 11:17 AM

Well,

I just got off the phone with MB regarding my car:

1) Regarding hesitation at highway speeds - They recommend cleaning the resonance flaps and possible replacment of vacuum transducers.

I have read many posts on this before and recently had the intake off to replace replace the GPs. But...

Where are these flaps?
What is recommended for cleaning and lube?
Should I have a shop clean the intake while it is off?
Should I replace anything else while I am in there? CCV hose? Fuel lines?
Where are the vacuum transducers?
How can I inspect these?

2) They said my lower control arm bushings are cracked. This is what is causing the car to shot to the left and right on uneven road surfaces. He mentioned that these were "hydrolic bushings." I have never heard of this term before. Does anyone have any experience replacing these?

#2 04-13-2004, 12:39 PM

SlowMoe:

I just had my Lower Control Arm Bushings replaced on my recently acquired 97 E300D. Two bushing kits were $108 and two hours labor for installation. They made a world of difference in the feel of the car. My car has 116K for mileage.

Bob

Mark Herzig · #3 04-13-2004, 01:25 PM

On mine, where the CCV hoses connect to the intake, they were totally gooked up. A machine shop should be able to clean your intake and cross-pipe. I manually cleaned the resonance flaps.

At 93K, If in fact the problem was carbon buildup in the cross-over and intake, I'd have to characterize your driving as mainly city...infrequent oil changes....

Now, the fact that you are a concerned owner on MercedesShop, I'd negate the characterizations above.... bottom line, bet cleaning would give you marginal results...

jdlow · #4 04-13-2004, 01:53 PM

SlowMoe:

I have just finished a 5 month ordeal regarding this on my E300D. I too thought the problem was related to the 3 intake baffles on the manifold. I dutifully took it off and cleaned all the soot which accumulated from the emissions Exhaust Gas Recirculation. OK this didnt solve my problem. At 60 mph and 2700 rpm the car would hesitate and start to puff smoke. Then hitting the gas pedal caused it to stop this behaviour.

Well the cleaning didnt remedy this problem. I sort of lived with it for 4 months when my Check Engine Light came on and the car began to hesitate at 40mph. After many trial and tribulations and a near miss at a dealership here is what I found fixed all my problems.

It is most likly you have either an electrical connection problem, or a vacuum leak. you need to check your vacuum from the pump and then at each of the following places

1. Vacuum Control Valve to the main intake baffle Front Left hand side of engine, (next to Air Filter)
2. Vacuum Control Value at the EGR. (just behind the main intake baffle)
3. Vacuum Manifold sensor line (Located on upper right hand side of engine on the manifold)

Make sure these lines and valves arent leaking.

Next check the electrical connections to the Vacuum Control Valves, these are located under the rubber tube going from the air filter to the manifold. Its best to take the tube off while doing this.

In my case I had 3 problems build up over time. My vacuum intake filter had become clogged reducing the vacuum, both electrical connectors to the VCV were corroded and needed to be replaced, and finally the vacuum manifold sensor linbe had a leak. I also replaced the VCV ($120 apiece) but in the end I dont think I needed to.

Dealer said it was the engine computer, and fortunately he was dead wrong ($1500 part if you can even get one).

#5 04-13-2004, 04:19 PM

JDLOW: Thanks for your feedback. This certainly will be greatly appreciated for anyone else having to experience your surging difficulties.

The Stealers 0, The customers 1

Great Job

slowmoe · #6 04-13-2004, 07:42 PM

Thanks for all the help, guys. Although I appreciate your experience, I have good reason to trust the shop that made these recommendations. So, I am going to start with them.

Mark's link is below - thanks for the great pictures!!

Can anyone point me to the resonance flaps?

Mark, what did you use for cleaning and lube on your flaps? Do you replace the CCV lines or just clean?

jdlow, do you think nyou are refereing to what the dealer calls "vacuum transducers?" Can you also point me to the vacuum pieces you mentioned?

Thanks again!!!

http://groups.msn.com/mherzig/e300dcarrepair.msnw?action=ShowPhoto&PhotoID=54

Mark Herzig · #7 04-14-2004, 09:21 AM

I dis-assembled the resonnace flaps from the intake and the crossover before taking to the machine shop for cleaning.

I scraped off layers of carbon and then used the walmart product
green (something or other) to clean.. I did not lube.. the flap is spring loaded and you are not supposed to operate it by hand so I left that as is.

I regard the flap cleaning as minor and possibly optional.

The CCV hoses ALL had to be replaced where they inserted into the intake manifold. When removing, they ALL broke off. The CCV lines were in good enough shape to reuse. The rubber had gotten very hard.

slowmoe · #8 04-14-2004, 06:23 PM

Do where are the flaps????

Mark Herzig · #9 04-14-2004, 10:54 PM

They are on the underside of the intake manifold and the underside of the crossover pipe. There is a rubber vacuum line that controls the opening/closing of the flap

Look at my picture of the newly cleaned intake manifold and you can see the connections

slowmoe · #10 04-15-2004, 05:33 AM

Mark,

I really must be dense!! I guess I am looking for a valve-like or butterfly-like component when I hear the term flap. In your "pic12" I see the 2 tubes that the crossover connects to, several passages into the head on the bottom and a few rubber hoses.

In your "pic10" I can see the underside of the crossover - but nothing I would refer to as a flap.

Would you please try to direct me again to the "flaps"

Thanks again for your help.

Dan

Mark Herzig · #11 04-15-2004, 08:20 AM

no problem..

ON Pic 10, when you remove the fastening plate from the crossover, there is a butterfly flap that pulls out that either block or enables airflow. There is the same thing on the intake (pic 11) but you cannot see it from the picture.

Look at Pic 12. The Two openings in the middle are where the cross over pipe connects. Between those two openings (inside the manifold) is another flap that controls air flow. You can see the housing above it but the flap is not visible. All of the hoses to the left that are mounted on the intake are controls, etc.. They are just mounted there with no mechanish internal to the intake itself.

slowmoe · #12 04-15-2004, 04:42 PM

Okay, now I am on board!!

So how do you clean- soak in a vat Simple Green over night?

Machine shop hot bath?

Mark Herzig · #13 04-15-2004, 06:08 PM

Don't think you can unattach the flap from the spring and internal mechanisms... I just scrapped off what I could and cleaned with simply green... were they perfectly cleaned? No.. not at all like the machine cleaning of the manifold... BUT I think, clean enough...

slowmoe · #14 04-16-2004, 07:52 PM

So, Mark, let me get this straight one more time... Did you remove the housings in order to access the flaps?

If so, were there gaskets to replace?

One more thought, the vaccum pieces attached to the flaps - are they what the dealer would rever to as vacuum transducers?

Mark Herzig · #15 04-17-2004, 10:59 AM

When you remove the 12mm bolts, you lift off the top plate and the flap is ATTACHED to the metal housing.. You lift it all out together.

Not sure about the transducer... Its all mechanical... can't imagine a lot going wrong with it other that maybe clogged...

I'll be interested to know what your mechanic was referring to.