Quote:
|
Originally Posted by Brian Carlton
That's quite bizarre. Can you describe the "percolating" in any more descriptive terms? I realize that it's difficult. However, I'm having trouble visualizing the exhaust gas pulses causing a resonance of the copper disc to the point where you would be able to hear it vibrating................but.............it's not out of the question.
The fact that the copper plate on the sealant exhibits the exact same behavior as the silver soldered plate is not a good sign. The installation is far more rigid with the silver soldered plate, and, therefore, the resonance characteristics of that installation will differ from the resonance characteristics of the copper plate sitting against the sealant.
To have the same sound with two different types of installation is puzzling.
|
Brian, perhaps another description such as "faint, high pitched tapping/crackling" ? It stops as soon as I ease back on the pedal. Before I had removed the egr valve, etc., I was driving it with the vacumn line to the egr valve plugged (the valve was apparently sticking and I would get clouds of black smoke when flooring the kickdown switch - advice from this forum gave me that solution - my local MB service advisor was not very helpful on this at all) . After I removed the valve, I wondered if the valve was always open, as it did not move freely (was it supposed to close upon acceleration?). So, right after I successfully had your copper disc & sealant installed (no leaks), and then replaced it with the soldered stainless part, I noticed this sound when accelerating with either part. So is it possible that completely removing the valve system alters the fuel ignition somehow, causing this? Everything I have read on this forum reassures me that the egr system is an add-on & the engine should function better without it? The stainless plate I soldered is 16 gauge, and much more substantial than your thin copper disc I had hammered to fit. But, since this presumably altered the exhaust gas flow somehow, the only thing I can imagine is this blocking plate causing it. I guess the sound reminds me of a pinging sound from gas engines which I don't remember the cause. I am not knowledgeable about engine mechanical details.