W124 E300 OM606.910 Cold Miss and Stumble Issue (I've Searched!) - PeachParts Mercedes-Benz Forum

valvecovergasket · #1 10-21-2019, 12:18 PM

Ive done quite a bit of searching in hopes of avoiding posting lengthy redundant topics, but cant seem to find anything that mentions this particular issue and before I drop it off at our local Mercedes shop I'd like to at least take a crack at solving it myself.

So far I think Ive read all the W124/OM606 stumble or miss threads.

Seems like most circle back to massive air bubbles from leaking plastic fuel lines, rear cylinder valve recession, failed return line check valves, timing chain issues, etc.
But none of the symptoms really match mine as it seems most have more issues or get worse once the engine is warm.

So... here's what Ive got:

Working with a '95 E300D with 265k miles.
Ive been maintaining this thing fastidiously for the last ~100k miles, have had it roughly 10 years.
Ive done new plastic fuel lines, new injector soft lines (replaced these several times during my ownership), fuel filters done on time, glow plugs have been replaced and work well.
EGR has been blocked off for roughly 50k of those miles and the intake manifold looked good when I pulled it, and I verified the operation of the resonance valve actuators. All looks well there.
I dont have any reason to believe the injectors have been removed as I havent done them, so I'll assume these are original.

The issue Im having seems to have cropped up just within the last month or so as overnight temperatures have dropped into the 30s/40s here in the PNW.

Itll start instantly after the glow plug cycle. Idles beautifully without missing a beat and could do that all day.
However, if the outside temp is below 40 or 50 and the car has been sitting overnight, if it's reved up following that cold start itll miss pretty badly and smoke a bit (blueish/whiteish smoke) if rpms >1000rpm.
Its a miss and down on power that feels a lot like air in the lines or partially gelled fuel.

You can drive through it by flooring it and it gets down the road sort of ok, but still feels like its running on 3 or 4 cylinders and definitely continues to smoke. Part throttle driving during this condition is basically a no-go unless its a crawl in heavy traffic, as maintaining 25mph is tough.
After about 2-3 minutes of driving it clears up and will run perfectly the rest of the day.
You can restart it several times during the day and not run into this issue (ie after 8-9 hours of sitting outside after work, no problems).
It seems to be only after a cold start with a full overnight soak.
Mpgs continue to be in the mid/low 30s and my oil sample reports are coming back really clean with no signs of excess fuel in the oil.

Ive checked for bubbles in the lines during this miss and I see half a second or so of a small bubble here or there immediately following the start, but other than that no sign of any air in the lines by the filter head, even while its missing.

As an aside - I typically run PowerService white bottle diesel treatment during the fall and winter to avoid gelling.

Any ideas of what to check or tests to run?
Im suspicious of the injectors or something to do with the injection equipment, due to the lack of bubbles and the general age of things... is there a cold advance in the pump that could be shot, or a sensor that drives that which could be bad?

Apologies for the novel! Wanted to get all the relevant info down

Diseasel300 · #2 10-21-2019, 02:27 PM

Start with the basics. If those injectors have never been out and serviced, they're junk by now. If they're peeing/streaming or have a poor pattern, you're gonna have rough running in cold weather.

You never mentioned glow plugs. If you have one or two dead, the engine will still start if it has good compression, but expect crappy running until those cylinders warm up.

You should never see *ANY* air in the fuel system. Ever. Not even after sitting for days. One bubble, no matter how tiny is too much. Fix your air leak. The OM606 has a seriously stupid fuel design and is extremely difficult to eliminate air leaks. Anything that's old and plastic needs replaced. Anything with an O-ring needs new O-rings.

valvecovergasket · #3 10-21-2019, 04:12 PM

ah yeah, neglected to mention the glow plugs but i did replace all 6 about 50k ago.
it had only 2 or 3 working ones at the time of replacement and definitely stumbled and coughed and wouldnt idle well for some time following a cold start.
id expect the GPs are ok now given their age and the smooth idle, and prompt non smokey, starts.

thats good to know on the injectors
in that case ill plan on pulling all of the injectors and having them serviced/replaced.
in some of the threads i ran across in my search folks were referring to bozio nozzles, im familiar with these from the vw tdi world, but it seems theyve perhaps been discontinued for the om606?
or am i ok just going to my local bosch diesel service center and havin these gone through with factory parts?

all of the plastic fuel lines and the soft feed/return lines underhood are new as of about 2 years ago, but who knows, maybe one has developed a small leak in the meantime.
so while im in there for the injectors maybe ill redo the plastic lines again just for completeness sake.

appreciate the guidance!

valvecovergasket · #4 10-22-2019, 03:26 PM

having done some more reading and verifying bubbles and whatnot during startup i have a couple more minor updates (hopefully useful if someone else stumbles on this thread)

- i have some bubbles entering the lift pump - more on cold starts following an overnight soak, less on warm starts. this has me suspicious of the prefilter, which i did replace when i did the plastic lines. i ran into some older threads on here and on the uk mb forum mentioning persistent leaks at the prefilter. hopefully another crack at a new prefilter will do it
- im reading about the delivery valves and it seems if i have the intake off and the injector lines undone, i may as well replace those DV seals and washers, and possibly put new springs in them as well. theyre not leaking now, but i have no reason to believe theyve ever been done as i havent done them.

ill update again once i have everything swapped - in case this thread comes up in anyones search in the future

spock505 · #5 10-23-2019, 12:41 AM

Quote:

Originally Posted by valvecovergasket

having done some more reading and verifying bubbles and whatnot during startup i have a couple more minor updates (hopefully useful if someone else stumbles on this thread)

- i have some bubbles entering the lift pump - more on cold starts following an overnight soak, less on warm starts. this has me suspicious of the prefilter, which i did replace when i did the plastic lines. i ran into some older threads on here and on the uk mb forum mentioning persistent leaks at the prefilter. hopefully another crack at a new prefilter will do it
- im reading about the delivery valves and it seems if i have the intake off and the injector lines undone, i may as well replace those DV seals and washers, and possibly put new springs in them as well. theyre not leaking now, but i have no reason to believe theyve ever been done as i havent done them.

ill update again once i have everything swapped - in case this thread comes up in anyones search in the future

Take a look through the 'wobble thread, might be some useful tips in there - if changing out DV seals would opt for holders too, not expensive either.

valvecovergasket · #6 10-23-2019, 11:28 AM

will do, thanks

for the holders do you mean the injector line clips? i did add those to the list

spock505 · #7 10-23-2019, 05:28 PM

The holders are just underneath the copper washers, these act as a one way valve maintaining pressure between pump and injector. Very important during cold start after sitting, made a huge difference on my set-up after trying many different ideas this was by far the most successful.

Wobble thread has a discussion on these, but also diesel300 went down the same path with similar results.

If you need to order I can send you contact details for dieselmeken in Sweden who supplied mine, very reasonable too.

Cheers

spock505 · #8 10-23-2019, 05:32 PM

This is one part of the valve,

This is valve and holder, ebay number:352698738329

valvecovergasket · #9 10-23-2019, 11:43 PM

appreciate the info!

for those stumbling on this in the future, heres the page where you guys discuss these in the wobble thread
OM606 engine wobble

im convinced though - that looks like a must while youre in there.
sounds like install was as simple as just continuing to scoop the next layer of bits out of the IP once youre below the copper washer?

would you mind passing on your contact at DieselMeken? i assume these were something they keep on hand for delivery, not something they had to machine special for you?

spock505 · #10 10-24-2019, 10:18 AM

Yup, its very easy to do although angled long nose tweezers is a good choice, need to get down the side to remove - you could use a magnet screw/nuts retriever but unsure on magnetic side of things.

Other thing to look out for is dirt from the surface making its way in, its hard to get it spotless so a good clean followed by a ring of grease around the top before removing, this holds onto anything loose.

Dropped you a PM.

valvecovergasket · #11 11-11-2019, 05:39 PM

quick update

working my way through the injector and DV overhaul

heard from the local diesel shop that (surprisingly) theyre happy with the condition of the injectors. they must have been done at some point.
he said pressure and spray were good and they dont think its worth breaking them open.

thanks to david and dieselmeken ive got a full set of DV holders, and the associated seals sitting on the workbench. new DV springs showed up today, so should have those back in tonight.
i put a new lift pump on while i had it all apart, and redoing all of the plastic fuel lines again. bit bummed to redo these so soon but seems the plastic around the end at the lift pump got brittle on one and it wasnt cooperating with my attempt at removal. ended up cracking a bit of the clip holder, so i figured id just redo them all.

and now with word that the injectors are ok, i will check the glow plugs while i have the manifold off, perhaps its time to do those again. i dont have my paperwork in front of me but want to say that i did them ~60-80k ago
reading some of the GP threads and folks mentioning some of their replacement intervals for GPs has me thinking i may have dismissed this as a cause too quickly. if this turns out to be the case certainly the symptoms are different than the last time i redid them.
and i know i put bosch plugs in there but many of the more recent threads suggest beru is the preffered supplier so if i do these ill switch it up again.

i tested both the crossover valve and the valve in the intake manifold with vacuum and both move and hold position fine.

so far no smoking guns...

valvecovergasket · #12 11-13-2019, 02:49 PM

another quick update -

DV seals and holders replaced, not much to it and a fairly straightforward job. tweezers certainly helped fish it all out of there though! and a couple of the orings were pretty mis-shaped and likely due for replacement soon.
the DV holders i pulled out looked to the naked eye to be in good shape i didnt see any weird wear or issues there.
i kept them around to spares or testing in the future.

i also put a new set of DV springs in there - which as noted in one of the threads i ran across were actually a decent bit shorter than the springs that came out.
just eye balling the spring rate it seemed like they were roughly the same firmness, but being shorter likely have quite a bit less pre-load on the valves.
i ended up with another set of new DV springs in some ordering confusion with my local dealer, so if anyone needs a set let me know! haha
otherwise ill keep them as spares or maybe throw them on ebay

ohm'd all the GPs and all are at 0.7, wiring checks out, so ill leave that all alone.

i think i did find a split oring at the main fuel filter, so perhaps that was the source of the air entering the lift pump.
i wonder too if that wasnt allowing a lot more air in after everything had cooled down and any gaps were exacerbated.
will see...

hope to have my new plastic line set in hand tonight and begin bleeding/purging/priming the setup today

probably wont know how things look after an overnight cold soak until later this week. but ill post more updates and some pictures later

spock505 · #13 11-13-2019, 04:11 PM

Fab, looking forward to end result.

valvecovergasket · #14 11-15-2019, 12:15 PM

first start after sitting outside at the house this morning and it seems to be cured.

ive been daily driving my diesel westfalia (read: 5000lb 65hp brick) in the meantime so i cant tell if the mercedes is more responsive now than it used to be, or i just became too acclimated to the westy and now the e300 feels like a rocket

but there seems to be a difference in noise for sure, it sounds smoother. i think its noticeably quieter during engine transients also

ill post some pictures later tonight

total parts list for the work -
new delivery valve holders
new (shorter - oem) delivery valve springs
new delivery valve orings and seal washers
new lift pump
new pre and main fuel filters
new plastic lines
verified glow plugs + wiring
injectors tested and were given the ok
new injector return lines
and a bunch of random seals and gaskets while i had the top bit of the motor accessible

valvecovergasket · #15 11-17-2019, 07:21 PM

several days of cold starts now, and i can definitely confirm the issue is fixed!

little late, but pictures of some of the bits in case anyone stumbles across this in the search

the new rube goldberg fuel line set, again...