OM602 2.5 turbo ticking sound at idle and low engine speeds

[seeyoulateralligator]

Hello everyone!
I've been reading this forum for a long time and I'm very inspired by the whole community that likes to understand and restore their old friends!

I have a 124th with an OM602 2.5 turbodiesel from 1992, which is an everyday car.
But there is some problem with the engine: after starting the engine, I hear its ticking on cold, which increases to 1400 revolutions, and then disappears sharply and the engine runs quietly. Only when warming up to 83-85 degrees, the sound noticeably subsides, but still remains a little.

Could this be due to the fact that before replacing the plungers, the car smoked under load and a carbon deposit could have formed, which creates poor combustion at low speeds? Sometimes after I stop for 5 minutes and then start the engine again and start driving, the power practically doubles, and then disappears.
Will the "Italian tuneup" help with this?

[t walgamuth]

sounds like an adjustable lifter is draining down at rest. It may be sticking a bit or maybe the oil being used is too thick. I'd add a quart of rislone to the oil for a cycle and give it a chance to coax it out.

[seeyoulateralligator]

Originally Posted by t walgamuth

sounds like an adjustable lifter is draining down at rest. It may be sticking a bit or maybe the oil being used is too thick. I'd add a quart of rislone to the oil for a cycle and give it a chance to coax it out.

it's more like nailing than hydraulic lifters noise

could it be due to old copper delivery valve rings?
rubber seals were replaced, but without new copper rings

[jdulle]

Mine does this exact same thing. It doesn't seem too serious. It does seem to be getting better from driving it a lot...but it remains to some extent. It could be air in the fuel system, I am planning on resealing or eliminating my fuel heater thermostat. Apparently there is an o ring inside there. I'm sure its old. I have already replaced most of the other fuel lines, and it still does it. Mine also starts up quick when cold but then misses occasionally after about 20 secs for about a minute. I think this is the air making it's way up to injectors from fuel heater thermostat. I also thought about the lifters and am planning some marvel mystery oil for a few hundred miles right before I change the oil.

[BirthdayBenz]

A couple things to consider.

The ticking sound at startup until warm, my 603 would do this. I ran some Liqui Moly engine flush and lifter additive and no more issues.

For the shutting off the car and then having more power after waiting a while and starting back up, My car also did this at some point in the past. I replaced fuel filters and lines which resolved the issue. My prefilter was visibly black and crud was clogging it. The IP would suck fuel and then clog the filter and power would be reduced. Then when it sat for a bit the crud would move away from the filter element until I ran the car again for a while.

[evranch]

My 2.5 turbo does the exact same thing. Clatters like a tractor at idle and smooths out perfectly above 1200RPM. This appears to be a known issue and some people have chased it in circles forever, changing injectors, lines etc. But I would just run with it if it runs well under load.

I ran straight Liqui Moly Diesel Purge through it when I first got the car which did diminish the clatter some.

Sometimes after I stop for 5 minutes and then start the engine again and start driving, the power practically doubles, and then disappears.

Your EDS turbo controller is probably going into fault and locking your turbo out. On a restart it will work fine, but when it detects that something is not working properly, it will open the wastegate and dump all your boost.

To see if it's currently active, pop the hood and rev the throttle by hand and watch the actuator on the turbo outlet. It should swing back and forth to limit boost as the RPM climbs above around 1500. You can also pop the ALDA hose off and put your finger over it to see if it's building any boost pressure.

If it's doing what I suspect it will build pressure after a restart, but then after it loses power if you pull over and do this test it will not.

I made a thread about tricking the EDS for an EGR delete. Haven't had a chance to do the full analysis I wanted to on the thing, unfortunately. There's always something else to work on...