OM617 knock on cold

[dymsza]

I'm looking for help diagnosing my OM617 knock:
https://www.youtube.com/watch?v=i6UnsaaWmhQ&feature=emb_title

My current idea is that it is injectors related.
Will be doing diesel purge and valve adjustment this weekend, if this will not help will pop test the injectors.

The knock will usually go away with in 30s second of driving at 2000rpms and then when car is warm I get a bit of vibration on idle but car runs great and has a lot of power.

What do you think? Can this be something more scary than injectors ? What other test would you do to determine it

[Diesel911]

You mentioned the valve adjustment already, condition of the injectors, fuel injection pump timing, valve timing and compression all can effect the fuel knock issue. If it is a fuel knock and it goes away after your engine warms up it is nothing serious.

Tests
pop testing the injectors

You are supposed to use the 2mm method to check the valve timing but you can get an approximation by lining up the timing mark on the back of the Camshaft Gear with the one on the front Bearing Tower and looking down at the Crank Damper and see what degree the pointer points to. There was some pics of this in the repairlinks.

A compression test to test the compression.

Checking or re-timing the Fuel Injection Pump.

[okyoureabeast]

Here's an interesting suggestion, if you just let the car idle from cold until warm does the sound go away?

If so, check to make sure you dont have a slight exhaust leak at the block to exhaust manifold.

I've seen that mentioned before as a potential source of weird knocking especially if it disappears when the car warms up.

[dymsza]

Originally Posted by Diesel911

You are supposed to use the 2mm method to check the valve timing but you can get an approximation by lining up the timing mark on the back of the Camshaft Gear with the one on the front Bearing Tower and looking down at the Crank Damper and see what degree the pointer points to. There was some pics of this in the repairlinks.

Yep Did it today look like I'm 2" ahead.


From what I can find this is OK?

[barry12345]

Loosen each injector hard line at a time. To establish if it is cylinder specific. If nothing is determined by that check the injection pump timing.

[dymsza]

barry12345 yeah I found the guilty injector and was able to eliminate that nock.