[Mercedesfanatic]

Hi all, My E300D is having heavy knocking sounds after I changed out the vacuum pump and Injection timing Device on the car. Car runs smooth for around 40 seconds when cold and then knocking starts. I suspect it is something to do with the fuel as I did take off the fuel lines to do the job. I am wondering where to go from here to correct the knocking. I went to a dealer and asked the foreman who said that there could be air in the injection system preventing a good spray from the injectors which causes the noise. What do all you guys think?

Video of the knocking
https://drive.google.com/open?id=0BzjNi6bcE4UlY2E1YVZGdmFnb0k

 

[Kajtek1]

Any air if fuel will be visible in clear tubings, so take a good look when pushing PPS to high idle.
I can only hope you did good timing when changing the device?

 

[Mercedesfanatic]

Any air if fuel will be visible in clear tubings, so take a good look when pushing PPS to high idle.
I can only hope you did good timing when changing the device?

I am sure that I made good timing. Crank and Cam centered at ATDC while the injection pump locking vane centered at 14.5 degrees. Car starts fine and idles and runs well for first 40 seconds or so. I will check the clear plastic hoses for air bubbles at higher RPM. Would they appear there when engine is off as well?

 

[Kajtek1]

Would they appear there when engine is off as well?

You might have stationary air bubble on top of tubing loop, but that would mean your system is in very bad condition.

 

[Mercedesfanatic]

Started engine and sound came as expected. There were no air bubbles at the plastic fuel lines. What should I do from here? Open up the metal fuel lines to bleed unseen air? The sound gets progressively louder as time passes.

 

[Kajtek1]

I would double check the timing.
Comparing flywheel with IP marks takes just minutes, while camshaft would take a bit longer.
Also I never done it, but there is test for timing chain stretch.

 

[Mercedesfanatic]

Hmm, I will look into double checking the IP timing to the crank pulley. I did take it out for a drive and found that if I coast, the loud noise stops completely and the engine seems back to normal again. As soon as I slow down enough to stop at a set of lights, the noise comes back. Also some grey smoke comes out from exhaust. Is the a big indication that timing is off? Thanks