97 E300

[Mr.Billyd]

Hello, yes mine is like all the 96-97 that suffer from the infamous 55mph cruise control surge. It doesn't have to be on Cruise, but it takes your foot out of the problem. I plan on watching real time feed back on a PC, focusing on the voltage going to the Resonance intake flaps. I believe the issue is a closed loop problem, So I would focus on looking for something that is in sinc with the surge. The funny thing is go to 70MPH and it's either gone or you can't feel it. Anyhow, I have a problem I would like to find the bottom of first. Is there a sticky with the 96-98 fuel lines regarding leaking? Or a good DIY. All my Clear plastic lines, shut off, etc, have been changed about 18months ago. My car is running rough at idle these days. I am seeing some air in my plastic lines. The most noticeable one is the line from the Main fuel filter that goes to the shut off. I can see the bubbles near the filter. When I increase the accel, with my hand in the engine bay, I can see them run off > where the line then appears to be solid fuel. Then I let off and they reapear. If the fuel supply seems to be diesel leak tight, how do you locate an air leak that doesn't seem to leak diesel??

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[TMAllison]

That ought to be a leak where #5 exits the filter housing or where #4 enters the filter housing. Confirm which line you see air in. http://bp3.blogger.com/_p71v9ofBM6w/...h/fuelflow.JPG

I guess it could also be the filter bolt orings too. Some folks crank that one too tight and pinch it.

[Mr.Billyd]

That helps knowing the flow.
I see air in line number 5. I run my fingers everywhere and cannot find fuel anywhere.
Should it be rare to see air in these lines?
It's nice to know the flow path.

Thanks.

Bill

[TMAllison]

In an ideal world there will not be any air anywhere. You should confirm the seals of top ends of #4 & 5, the spin on filter and the orings on the hold down bolt.

[Mr.Billyd]

Thanks for the feedback.
I am just about to pull the trigger at Fryerpower for the complete kit.
If I am going to go hunting, I want to have the o-rings ready to go, I may as well buy a new fuel filter and have that ready. Has anybody posted the correct size for all these o-rings> I have access to these viton o-rings at work. Now this morning with the car cold I have about 1 inch of air on line (number 1 per your drawing) Heat exchanger to the prefilter. The air is on the last 1 inch as it goes to the prefilter. Is the air leak on this line? or is it the highest spot and it just travels there?

I have never changed the fuel filter myself on this car.
The center bolt you mentioned has two o-rings? This seals the main filter? Is there a torq spec, you say they sometimes get twisted.

Thanks,
Bill

[TMAllison]

I created the list for fryerpower for the 606.962, no affliation. See post 2. http://www.mercedesshop.com/shopforu...d.php?t=177588

The preheater to prefilter line always drains back at shutdown. Ignore that, it normal.

The fuel filter ought to come with the orings for the bolt. If it doesn't you aren't buying german filters like mahle or knecht.......I lube the filter oring with fuel (after first prefilling it with fresh diesel), then spin it on hand tight like an old style oil filter. Then snug the bolt a 1/4 turn or so.