1996 E 300 Diesel, 606 engine, non turbo. This version has diagnostic codes capability yet no codes as of yet. Symptom, sometimes, very aggressive bucking, 2500 to 2800 rpm. It seems it has to be fuel rack pulsating. I'm trying to put myself in the position...If I replace the injection pump, and it does not fix it, what else could it be??? I'm sure I will get many suggestions that I have already tried but please don't hold back. I am looking for the one thing I have overlooked.

Did you check all of the fuel lines for air leaks? The little o-rings go bad after a while. There are a mess of hoses in there that could go bad.

Clogged fuel filter?

Look for the easy stuff first

I have cleaned all line connections and sprayed with tracing powder to watch for a fuel leaks but...is it possible to suck air and not leak fuel ??

When I had issues with my car earlier this year the lines were sucking air but not leaking fuel.

This could be surging due to resonance flaps malfunction. Sometimes all they need is a good cleaning. Search on Resonance Flaps for others who have described symptoms and cleaning.

Best Regards,
Jim

I agree with the possible resonance intake manifold and resonance tube switchover valves Y22/6 and Y22/7 being gummed up. Mine did that too before I cleaned out the diesel goo and also replaced the valves. Bypass of the EGR will eliminate surging too. Use the search functions to help with this.
Steve

My 1996 had the same symptoms from time to time. All winter long it's fine. It only happens in the humid/warm weather. In my case, as a temporary fix, I can reach to the back side of the EGR (with gloves on if the engine is hot) with the fingers of both of my hands. If I push/pull the diaphragm up and down 5 or 6 times the surging goes away. I clean the EGR out each Oil change and it seems to keep it in check. I'd like to bypass the thing but I haven't had the time to retrofit something. I just keep it clean. Hope this helps you figure out/eliminate what the problem might be.

I have decided to inspect all the fuel line o-rings, all of them.
I have also decided to clean the carbon soot from the intake manifold, assembley. That will be a chore.
As an update, we have seen this complaint on 1995, 124 chassis 606 engines and 210 chassis with 606 engine and replaced both Y31/1, (EGR Transducer) & Y31/2 (Pressure control flap transducer) with success. We replaced them early on with this auto with no results. All vac lines have been inspected, vac applications tested and all found to work. In theroy, the Y22/6 (Resonance Manifold switchover valve) & Y22/7 (Resonance Line switchover valve) should through a code if malfunctions. I have unpluged and run for grins and found 'Check Eng" light comes on. But with above suggestions, I have nothing to loose by replacing them. Again, the EGR is electrically monitered and should code, but a good cleaning is still a good idea. I will try the suggestions above and let you know how it comes out.
* I would like to pass something on I have found. We are lucky to have a nice customer and time hasn't been an issue yet. I have viewed the operation of the 124 chassis 606 on other cars that come in and also viewed the operation of the 210 chassis 606, non turbo's.
Resonance Intake Manifold: From CTP to 2550 rpms, both 99/2 (Intake Line Flap-middle of long intake pipe on top) & 99/4 (Intake manifold flap) are closed. From 2550 rpm to 3350 rpm, 99/2 opens & 99/4 stays closed. 3350 & up both are open.
* In viewing a 124 chassis 606 engine, the above was true.
* In viewing the 210 chassis 606 engine that I am working on, I found the opposite happening from 2550 to 3350. 99/4 would open and 99/2 would stay closed. All electrical connections seemed factory. I swapped the vac lines at the swithover valves, Y22/6 & Y22/7, to generate the operation the book calls for and the car runs much better and more pep.
You might know the Mercedes HHT showed 99/2 opening when it really was 99/4 opening before the swap.
* Here's the kicker, another 210 Chassis 606 rolled in for an oil service and it was doing the same thing. I don't know if I have found a true MB foul up or not.
Could this community with the 210 Chassis 606 engine look to see how there resonance flaps are working? This is very hard to put into print and know if I have described what I have found in an understandable way or confused everyone.
Thanks, Michael

I have a 97 E300 W210 with the 606 engine.
It seems MB design of the Resonance Flaps in the intake have many problems. I guess they dont do recalls for bad parts. My car has 70k miles and is pristine. Not much soot to speak of.
Can someone give me detailed explaination of how these expensive (2) transducers work?? I would also like to know how to check them, Ie resistance checks or electrical checks? I dont want to willie nilly change them. I swapped them around and it seems to have worked.
The problem I notice is - if I put it on cruise control at 55mph or just hold my foot steady at this speed - the car goes into surging mode- rpms also track the feeling. At idle is this flapper suppose to gyrate all the time?

Can someone point me to a link to help me isolate which of these is bad- I would hope they both are not bad.

Bill

It is better to start your own thread and to describe ALL you problems at one time in one place than to tag onto old threads.

You'll get better help that way.

The first thing to do is ALWAYS fix the fuel leaks first (see your other thread). They can be the "cause" of other issues.

After that, if other symptoms remain, THEY can be dealt with in a logical progression.

Very often a good cleaning of all the gunk that collects in the egr and resonance flaps helps surging/lack of power issues.

__________________
Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)