Well, after much work I finally got a used head and put her back together. I did ALOT of "while I'm in there" and deleted the EGR entirely, to include the diode and resistor method. Also replaced every possible seal I could, water pump, thermostat, all if the clear fuel lines, deleted and bypassed the fuel thermostat, cleaned the intercooler, and got some shiny new glow plugs! God some all new Bosio injector nozzles installed and balanced by grazer as well. After all of this no check engine light or glow plug light, but the engine sounds like its nailing pretty bad, clears up at about 1400 rpm. So my thoughts are the pump needs to be adjusted due to the brand new nozzles set at 135 bar, or the chain tensioner died. I already ordered a new tensioner (cheap insurance) and checked the fuel lines for bubbles. I cant see any bubbles at all. So thoughts anyone? How picky is the tensioner when it comes to priming it? All the timing is exactly where It was prior to head removal as I locked the crank.

Did you block off the egr vacuum transducer vacuum line leaving the transducer electrical plug still connected ? , diode and resistor method requires this where the other early method has it unplugged.

Possible its still getting exhaust fumes in the mix ?

Yes I left the transducer plugged in, and just capped off the vacuum line, and no exhaust can get in due to the fact I bought the delete kit from diesel pump UK. I'm pretty sure it's either injection timing or chain slack.

My 98 E300 nails slightly at idle too.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

I think I'm just going to accept it sounds like a tractor at idle, it's not exactly ryhtmic, kind of random I would say. New tension is in an did not fix it.

Chain stretch isn't really a thing on a well maintained double row chain. The tensioners really don't go bad as well if you maintain oil changes regularly. They go bad when you neglect oil changes and the oil pressure galleries get clogged...

The tractor sound is injector nailing. Bad delivery valve springs, leaking delivery valves, injectors that aren't broken in yet, worn or leaking injectors will cause nailing as well with other variables too.

It's Nothing to worry about on a benz diesel, and it's pretty normal. Sometimes it's easy to rectify and sometimes it's not. If it's still getting good MPG and good power and not smoking a lot, it's fine.

I'm at 210k on original injectors with very little black smoke at WOT so I'm not bothering to send mine to greaazer yet

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Only diesels in this driveway.
2005 E320 CDI 243k Black/Black
2008 Chevy 3500HD Duramax 340k
2004 Chevy 2500HD Duramax 220k

Well that is mostly reassuring! I have no smoke and power seems just fine so it sounds like I'm just gonna roll with it for a while.

Try a bit of a Cetane booster such as the Power Service or Stanadyne line. We get shyte fuel in Arizona since we went to ULSD.

4 Best Diesel Fuel Additives of 2018 (And Why They Work)

Use at the recommended rate. "More" doesn't mean "better".

Stanadyne is the best but can be hard to locate. The Power Service is also a good choice, either the "Diesel Kleen" or the "Fuel Supplement". We don't need the anti-gel properties of the supplement but sometimes it is all I can find.

I won't guarantee it will cure your problem but it works wonders on the OM615-617 series.

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“Whatever story you're telling, it will be more interesting if, at the end you add, "and then everything burst into flames.”
― Brian P. Cleary, You Oughta Know By Now

Well just did a 450 mile trip up thru Julian, CA from Yuma, AZ....wow I no understand the love for these engines! I did alot of mountain driving and it just ate it up! The slight turbo wwhistle is great and though not many people are fans of the W210, it handles amazing and is the smoothest ride I've owned. By my calculations I averaged 31 mpg which seems reasonable with 2 kids, the wife, and a loaded trunk. Nailing still persists but its only below 1000 rpm. The only hiccup was a check engine light on the freeway.....the boost sense line popped off. Crisis averted!

If you have a bio diesel plant near you, try a tank of straight B100 and see if that quiets it down. It did for me.

The OM61x and OM60x engines can tolerate B100 but it will eat the standard o-rings in the fuel system if used consistently.

The CDI (OM648/OM642/OM651) engines cannot tolerate bio above 5%.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

I would carry a cheap OBDII reader with you. My favorite for tossing in the glove compartment is the Autel Maxiscan MS300, $16 at Amazon

Or if you have an Android phone get one of the cheap OBDII to Bluetooth adapters and use your phone as a scanner. For some reason they won’t work with an iPhone.

This will only read engine codes on a W210 but may be enough to get you out of limp mode on a long trip.

Check that boost hose and make sure it’s not becoming dry rotted.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

I don't thing we have any Bio here in Yuma, AZ sadly, but I do always have a Scangauge II hooked up so the code was obvious P0243 i think it was. I did just try to isolate the noisy injector by loosening the injector line on each injector. Number 4 seems to quite it down the most but then again they all seem to quite it down. Time for delivery valve seals and springs?

When I had my 96 E300D, my delivery valves started to leak. After checking on the forum, some of the posters stated that you did not have to change out the copper crush washers, and they did not need to be replaced, just the rubber seals. Prior to doing the job, the engine ran as smooth as silk, with no nailing what-so-ever. After doing the delivery valves, the engine sounded like the tractor you mention. I decided to do the delivery valves again, only this time changing out the rubber seals along with NEW copper washers. Torqued them to speck as I did the first time, and the engine was back to it old self, as smooth as silk with no nailing what-so-ever. Good luck with your vehicle.

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96 E300d

I actually read your post on another thread and this is the exact reason I'm changing them out! If that doesn't fix the noise, then I will consider my car a head turner, haha.