OM606 engine wobble

[spock505]

Don't hold out much hope for finding out the issue but here goes, engine has a noticeable wobble at idle - this has been present since I bought the car but much improved, what' has been done to help, so far:

- New engine mounts, Meyle

- Two sets of injectors

- Replaced head, timed up correctly using gauge, re-set timing peg

- Tank flush

- New DV's

- Replaced O rings, filter several times

Out of interest today, pulled the main harness cable connector - revs dropped but wobble still present, hopefully this video shows fault better (cable plugged back in)

https://youtu.be/Gabu-rNVClo

[Diseasel300]

Your video link doesn't work, at least not for me.

You don't mention compression. Low compression on one cylinder or a problem with fuel injection on one cylinder will cause a lopey idle.

[spock505]

Yup, good point, comp test done prior to head swap, all good - bores were also in good shape on inspection, no blue smoke or blow-by at present.

Can you try link again, edited settings

[Diseasel300]

Works now.

The 603 in my SDL rocks a bit at idle too and I've not yet narrowed down the primary cause (it isn't compression in my case). It comes and goes, sometimes smooth as glass, others a bit wobbly. I suspect a valve that's not seating properly, an injector that's hanging up under certain operating conditions, or wear in the IP. Off-idle it's smooth and makes good power and economy, very low blow-by, but moderate oil consumption from a trashed turbo seal.

[spock505]

That's pretty much how this is, sometimes hard to detect and a little worse when hot.

Its most noticeable at sitting at lights, or when you are stationary with drivers door open, the edge really accentuates the rocking movement.

Couple of times after an 'Italian tune-up' went altogether, well at least for a few minutes.

Last time I did the DV's I noticed what looked like residue on the surface of plunger, (this is the bit that sits way down inside pump) so today pulled 5/6 out, plungers too - my intention was to swap out with OM606.962 parts which I had to hand, unfortunately all the part numbers were different so didn't risk it.

The plunger did have small build up but this looked worse than it actually was due to locating notch running up one side, from the top it could be mistaken for pitting.

Carefully re-assembled 5/6 torqued 35nm, engine eventually fired - exactly the same, no difference whatsoever.

It's getting quite sad now as not only do I know all the socket/spanner sizes, but torque values too, the above including manifold removal probably took less than two hours

[spock505]

Perhaps there's an idle sensor which is faulty hence unplugging main loom didn't achieve anything?

[Diseasel300]

If this is the 124 vehicle, it should be a mechanical IP with the EDS solenoid on the back just like the 603's had. If so, the EDS solenoid only adjusts idle speed, not unlike the idle speed plunger on old carbureted cars with A/C. Idle speed and operation is entirely mechanical, so no sensor can have any effect on how the IP runs. At idle, the ADA (or ALDA on turbos) isn't even in the circuit so it all comes down to how the IP is tuned internally. That's why I suspect IP wear in my case, especially given the rough history of even getting a working IP in my car.

[spock505]

That makes sense, thanks -

I did notice some pitting around where the copper washer sits, this was the other reason for wanting to swap out with 962 bits which looked identical.

..back to the drawing board as they say...

[pimpernell]

Originally Posted by spock505

That makes sense, thanks -

I did notice some pitting around where the copper washer sits, this was the other reason for wanting to swap out with 962 bits which looked identical.

..back to the drawing board as they say...

This thread gave me a lot of incite when I did my delivery valves. Might be some information that can be of help. Good luck!!







OM606 engine (W210 E300D/TD) delivery valve seals

[spock505]

Thanks, but already changed DV's a while back, this time was to replace parts which looked a bit suspect.

Had a quick search for this issue, not much but did find this - something I would never have looked for.

Originally Posted by weisskasten

Hi
Yes problem solved. There was a hairline crack in one delivery valve housing. I discovered it when I pulled them out to check. Upon retorqueing, it cracked in half. Apparently when it warmed up the crack would worsen? Anyway, a new valve has been installed. I had to then change the motor mounts(shot), and the belt tensioner(also ruined from bad motor mounts) Now it is so quiet and smooth. Wow!!!!

Also, does anyone know if these are part numbers indicating differences between OM606.910 and 962, they look identical ?

[spock505]

Re-visited this again today after watching this video, it really shows the importance of having correct height of holder (screw in bit) - although this is an earlier pump the principals are similar, here the adjustment is carried out using rotating plates held either side by bolts.

https://www.youtube.com/watch?v=uNn_Ko5dsDM

On later pumps such as mine there is no such adjustment but correct torquing must be critical, with this in mind I went back to check torque as undoing always seems way too difficult.

Marked random injector holder with pump body, unscrewed then re-torqued - it was within 1mm of original setting so didn't bother with rest, unlikely I would have changed torque wrench between holders.

I had considered the possibility of accidentally setting the wrench to pounds giving around 45 nm, but this wasn't the case.

Whilst in tinkering mode my attention turned to the altitude sensor, this has always been of some concern as it was badly bent to one side by previous owner/mechanic - although now straightened and vac tested never 100% sure, decided to drop the mixture down by screwing in the adjustment (original position marked) - this did nothing for the wobble but did improve the overall running, slight change the engine note under high revs which is quite pleasing -

Its running great and pulls like a train, going to leave alone before I break something heading into winter

[TMAllison]

Has the trans mount ever been replaced?

[spock505]

Still original, removed a few times, visual inspection seemed okay but could be wrong.

Everything else (engine mounts, rear/front wheel bearings, control arms) needed replacing though, would this cause a wobble at tickover?

[Texasgeezer]

To spock505,

In your third photo yesterday, ( probably just my old eyes and the shadows ), it looks like the burnished area of the copper washer is thinner where the shadow is ( about the 6:20 ) position. Also the burnished area between the 8 & 9 o'clock position appears to be a little thinner. If the burnished area is thinner, then the seating is probably not uniform for that delivery valve position.

I guess the shadow might make it look like un-burnished copper in the photo, but the color appears to be the same as the outer edge of the copper washer.

About six months ago I changed my motor mounts and delivery valve copper washers and o-rings during the same session. After it was all back together I had more of a rough shaking idle than before. Luckily with a few weeks driving it smoothed out. Don't know if it was the motor mounts settling in or the delivery valves sealing better. I did decide that I would slightly polish the copper washers the next time I replace them. This is because, visually, the surface of the new copper washers did not appear to be as smooth as they could be. I thought that if they weren't uniformly smooth then they might not seal properly. (I tend to overthink things, so I'm probably being too concerned.)

[spock505]

Texasgeezer, spot on, there are different areas of burnishing which is something I looked at closely using an eye glass.

Here's the thing though, working out how these operate starts to whittle down my previous understanding, originally I thought the copper washer played some part in sealing the valve during pressurized delivery of fuel via injector, however this is not possible - let me explain why..

The copper washer in previous pumps is shown further down the assembly and not at the top, my guess is both copper washers are in fact 'crush' washers to ensure correct internal measurement when torqued.

Secondly, if you remove the two parts below the washer and measure inside the holder they cannot move anyway, once torqued down that's it - very snug fit.

My guess is the small pistons referred to in the video sit inside the sleeve pushing through the core ejecting X shaped spindle, this is the only part that is free to move and return back under spring pressure.

Careful observation of the sleeve show no vertical wear marks further confirming this theory.

That doesn't mean the copper washers are not important, they are to allow proper seating of internal sleeve parts, so this leaves one question - why the mirrored polished mating surfaces?

Two possibilities, firstly to allow centralization and alignment during assemble and operation, and also to accommodate any sideways vibration attributed to piston motion.

TM, ordered part number 124 240 0618

Cheers