I did not want to hijack my own post, and I as well am very interested in this subject, so I think you should start a new post on this subject.

I am particulary interested in the function of the damper located in the cross-over pipe. The reason being is that it works ALMOST in tandem with the closing and opening of the EGR valve. In other words when the EGR opens this damper closes, and vice-versa (There is a lag between the two, which is engine RPM dependent).

So that if someone blocks or disables the EGR valve than theoretically they should also disable this damper as well. No one however has mentioned that.

Phil

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'95 E300 Diesel, 264,000 Miles. [Sold it]

Do you have a tank strainer? Is it clear?

A car enthusiast friend of mine just called me to suggest another possibility. Although he is not a Diesel expert he said that most cars have a "Check Valve" that prevents the fuel from going back into the tank when the engine is stopped.

If that's true in my case than maybe that valve is malfunctioning letting the fuel drip back into the tank, but only when the tank is less than 1/2 full, as there is less back pressure in that case. When the tank is full, than the back pressure in the tank prevents the fuel from going back into the tank. It makes sense. Does anyone know if this car has such a valve, If so where is it?

I also used a very strong flashlight, and looked at the formerly clear (now almost opaque) fuel line that enters the pre-fuel filter. I noticed a 1/2" air gap there. When I started the car, the fuel was only dripping in, not ever filling that void. That does not sound normal either.

Phil

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'95 E300 Diesel, 264,000 Miles. [Sold it]

Can't comment on the check valve, but the air in the prefilter is normal. It doesn't ever go away completely, but, it seems to be smaller with a full tank of fuel.

Your car is full of computer engine management controls. I am assuming you do not have a check engine light on? My initial guess is that the TPS is not telling the computer in a timly fashon that you have pressed the throttle. so it could be a TPS, MAF or host of other computer related sensors. I wish we had more info on various tests you may have done.

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1981 300D 147k
1998 VW Jetta Tdi 320k
2001 Dodge Ram 2500 141k
1979 300D 234k (sold)
1984 300D "Astor" 262k(sold)
Mercedes How-To and Repair Pictorials
I love the smell of diesel smoke in my hair

Thankfully this one does not have a check engine light but it does have the diagnostic port in front of the battery area. Not sure what all kinds of codes you can get out of it.

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Jim

I can eliminate electric/computer related problems as being the cause, as I checked and double checked each and every circuit, component, and wire for a possible malfunction. Non is evident. I was also able to read the limited diagnostic port and no faults are evident.

I am going with the consensus of the forum that the problem is related to a small leak in the fuel system, that only becomes evident, (as Brian and others suggested), when running with less than a full tank.

The other possibility is a malfunctioning fuel line back-flow check valve, but I am not sure if my car has one, or even how to test it if it does have one.

Phil

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'95 E300 Diesel, 264,000 Miles. [Sold it]