Surging diesel between 50-60 mph - PeachParts Mercedes-Benz Forum

rbennett · #1 10-02-2006, 03:47 PM

Hello All,
I recently purchased a 1996 E300 D with 154,000 miles. Between 50 and 60 miles per hour the car surges. The surging feels as if you are lifting slightly from the accelerator and then pressing the accelerator down again. The surging is mild but noticeable. The frequency is rapid. Below 50 and above 60 miles per hour there is no surging and the engine runs beautifully. I've replaced the fuel filter, pre fuel filter and run a can of Lubro Moly Diesel Hi-Test as a suggestion from the local dealer. Does anyone have any thoughts on what else to try? Any and all help is greatly appreciated. Thank you in advance.
Richard

#2 10-06-2006, 08:14 PM

I have a 1996 e300d. I have found that mine will do the same thing only in the warmer/humid months. When it's cooler and dry, no problem. For me, I noticed that if I manipulate the EGR diaphragm on a warm engine (with gloves on!) the car behaves beautifully afterwards. Lasts about 500-750 miles. I am thinking about replacing the EGR thinking the rubber diaphragm is cracked or something. I've also heard it's a software problem OR that the butterfly valves in the intake manifold (aka resonance flaps) are the issue. Not sure.

e300D97 · #3 10-07-2006, 03:07 PM

Quote:

Originally Posted by rbennett

Hello All,
I recently purchased a 1996 E300 D with 154,000 miles. Between 50 and 60 miles per hour the car surges. The surging feels as if you are lifting slightly from the accelerator and then pressing the accelerator down again. The surging is mild but noticeable. The frequency is rapid. Below 50 and above 60 miles per hour there is no surging and the engine runs beautifully. I've replaced the fuel filter, pre fuel filter and run a can of Lubro Moly Diesel Hi-Test as a suggestion from the local dealer. Does anyone have any thoughts on what else to try? Any and all help is greatly appreciated. Thank you in advance.
Richard

Richard,

Do a search on "surging".. I too had this problem and found it to be related to the resonance valves. I took the intake manifold off and cleaned the flaps. ALso check the vacuum line that comes off the drivers side of the manifold and goes to a vacuum switch on the firewall, its a short hose about 4 inches. Mine was cracked. I am on vacation this week and dont have access to my files. If it were a solenoid related to the flaps you would get the "check electronics" message following the check engine light. I could also be the EGR valve sticking, by removing the entire intake system and cleaning it out you can usually remedy this situation.