Noisy injection pump rattle - 602 300D

[amg280]

Hey folks,

Lately it seems that at a specific rpm around 2K or so, there is a fairly loud rattle sound coming from what appears to be the back of the injection pump (near firewall side).

My diesel mechanic (in the biz for 30+ years, exclusively mb) is stumped, as am I. It sounds like a loose timing chain hitting the case. He got the stethoscope out and did in fact isolate it to the pump. Should I be worried? It only does it at that specific RPM. It doesnt sound good though.

Its not the belt shock rattle that your probably thinking of!!

Thanks for any input.

[Diesel911]

One of the Members had something vibrate loose in his IP. Also sometimes bearings go bad or parts of the Governor go bad; not often but ounce in awhile.
I am not familiar with your IP but on mine I can remove the Vacuum Shutoff and the ADL and take a peek inside. I do not know if this can be done with yours.

Also mine has a reas support bracket. I that bracket was broken or the nut/bolt back there was loose it might make som noise. So, it might be a good Idea to do a good look and feel around the IP to see if it is something outside of the pump that is loose instead of inside of the IP. Even with a Stethoscope it is sometimes hard to trace exactly where a sound is comming from as sound conducts through the solid parts.