[The Dark Side of Will]

I found my first diesel headache on Monday:

Black death on #6.
The car is a 2005 E320 CDI in the United States. OM648 engine. ~215k miles on the car. I have NOT had an injector flow test or injector balance test done yet. I bought the car at 168k, and have no maintenance history before that.

I do almost all my own work, but I took this to a shop because I can and I didn't want to mess with it this week.
The shop is trying to sell me on an injector refurbishment at ~$120/each. That doesn't seem terrible. I've actually been wondering if I have a leaking injector, as the best mileage I've been able to get is 30-32 mpg at 80 mph. The dash display tells me numbers above 40 mpg on trips like that... I find it difficult to believe that the dash display could be THAT wrong and the car still functioning correctly.

Once the immediate problem of removing the injector and cleaning the carbon deposit has been overcome, is there a reason not to reinstall with new seals? Will refurbishing the injectors get my mileage back?

What more do I need to know about the shop that does the refurbishing?

 

[mersum1es]

Bottom surface and injector sealing surface must be checked for abrasion wear marks. If there is sign of wear by gas flow, they must be refined.

Sometimes injector will die if it is reaaly badly stuck, and you will need new anyway... and very often black death is caused by cracked nozzle holder! Holder nut is sold separately and is 'universal' part.

If garage has never sone that before, emphasize they clean thread hole properly, so bolt won't penetrate debris to water jacket.

 

[glenlloyd]

That MPG is pretty low, but it also depends on the time of the year...winter? Winter blends provide 20% less btu content because of the blending. It also depends on how hard you hammer the go pedal.

If you think your single injector is bad...you should see mine. I have worked on my problem but it's going to take a lot of work to get it all out of there....a lot. I will probably sell it before that time comes...not really interested in that project. As for what contributes to the 'black death' I am not convinced that it's injector issue as much as it's the decomposition and turning to goo of the insulating pad in the engine cover.

I don't believe that the computers can accurately determine mpg. They don't measure fuel flow so I don't see how they could be accurate....take them with a grain of salt. I don't generally even view the command mpg figure at all anymore.

I don't drive 80 in this car, or better said I haven't driven 80mph in this car yet. My winter mpg for the few miles I drove it in winter weather this year were 34ish (measured at fills only, and that was 70-75 mph.

EDIT: a friend with a CDI got a quote of $600 per hole just to clean up the mess.

Steve

 

[The Dark Side of Will]

Thanks for the help!

370 ftlbs at 1800 RPM sounds like a muscle car to me, so that's how I drive it. 😁
That MPG is with summer fuel. My winter fuel mileage drops a couple MPG, but not 20%.

The shop I took it to is an indy shop. They work on Benzes regularly enough... They have an SDS or professional level clone (Autologic?) and correctly diagnosed my SBC failure last fall. They've worked on diesels generally and Benz diesels specifically before. The owner knew what he was looking at when I showed him the injector pictured above.

The shop is quoting me one replacement injector and refurbishment of the other five. I think the shop they're going to have do the refurb is United Diesel in Alexandria, VA.

Bottom surface and injector sealing surface must be checked for abrasion wear marks. If there is sign of wear by gas flow, they must be refined.

So if the injector sealing surface in the head is damaged, it needs to be resurfaced. Is there a tool to do that in the car or does the head have to come off? How is damage to the sealing surface in the head usually repaired?

What do I need to look for on that injector to determine if it can be reused or not? I should have them send the one over to the injector shop as well and determine if it can be re-used BEFORE breaking the seal on the new one they ordered.

Sometimes injector will die if it is reaaly badly stuck, and you will need new anyway... and very often black death is caused by cracked nozzle holder! Holder nut is sold separately and is 'universal' part.

If garage has never sone that before, emphasize they clean thread hole properly, so bolt won't penetrate debris to water jacket.

So the nozzle holder can be replaced if it's the cause of the black death?

I'll make sure to mention that they need to clean out the bottom of the bolt hole as well, and make sure no debris went down into it.

 

[The Dark Side of Will]

I don't believe that the computers can accurately determine mpg. They don't measure fuel flow so I don't see how they could be accurate....take them with a grain of salt. I don't generally even view the command mpg figure at all anymore.

The ECM knows (should know...) EXACTLY how much fuel the injectors flow and it knows injector "on" time to the 0.1 millisecond. The SBC knows how fast the car is going. The data is certainly on the car to calculate tank average fuel economy to within 1-2% easily. However, the dash is telling me tank average of 42 mpg when the fuel pump and odometer tell me maybe 32 mpg. That's a big error. @$$uming Benz is knowledgeable enough to program the calculator correctly, and given that the speedometer checks <1mph of GPS, calculator error that big would only come from fuel flow the ECM does not know about => Leaking injector

 

[glenlloyd]

The ECM knows (should know...) EXACTLY how much fuel the injectors flow and it knows injector "on" time to the 0.1 millisecond. The SBC knows how fast the car is going. The data is certainly on the car to calculate tank average fuel economy to within 1-2% easily. However, the dash is telling me tank average of 42 mpg when the fuel pump and odometer tell me maybe 32 mpg. That's a big error. @$$uming Benz is knowledgeable enough to program the calculator correctly, and given that the speedometer checks <1mph of GPS, calculator error that big would only come from fuel flow the ECM does not know about => Leaking injector

The ECU is probably telling you instantaneous and not average...but I don't pay attention to it anymore really. I just filled today, had a combination in the tank that was half winter and half summer, fill took 10 gallons and that equated to 36mpg. The dash had been telling me 41.2 last I checked yesterday.

I agree, it should be specific, but like the MFA on VW the fuel efficiency metric isn't precise. Now maybe it can be changed in Command to report a different format?

Steve

 

[mersum1es]

The shop is quoting me one replacement injector and refurbishment of the other five. I think the shop they're going to have do the refurb is United Diesel in Alexandria, VA.


So if the injector sealing surface in the head is damaged, it needs to be resurfaced. Is there a tool to do that in the car or does the head have to come off? How is damage to the sealing surface in the head usually repaired?

What do I need to look for on that injector to determine if it can be reused or not? I should have them send the one over to the injector shop as well and determine if it can be re-used BEFORE breaking the seal on the new one they ordered.

So the nozzle holder can be replaced if it's the cause of the black death?

I would not swap/refurb them all blindly, if they have an SDS they can check correction values of injectors, thats one of the indicators of inner wear (usually worse at cold conditions). Then spill of leak test is next. Those can be done without moving injectors. If better diagnose is wanted, injectors must be bench tested. Howevere I would relay on those two tests...

There is a tool for bottom hole refining, cheap chinese on ebay available, but if carage is doing lot of common rail diesels, they should have profesional tool set for that. Shouldn't be unheard repair method, and needs no head off.

Yes nozzle holder is common and cheap part, easy to swap when injector on table.

 

[The Dark Side of Will]

The ECU is probably telling you instantaneous and not average...but I don't pay attention to it anymore really. I just filled today, had a combination in the tank that was half winter and half summer, fill took 10 gallons and that equated to 36mpg. The dash had been telling me 41.2 last I checked yesterday.

It definitely says "average" and behaves like an average on long trips.
I've also NEVER gotten 36 mpg in the car.

I would not swap/refurb them all blindly, if they have an SDS they can check correction values of injectors, thats one of the indicators of inner wear (usually worse at cold conditions). Then spill of leak test is next. Those can be done without moving injectors. If better diagnose is wanted, injectors must be bench tested. Howevere I would relay on those two tests...

There is a tool for bottom hole refining, cheap chinese on ebay available, but if carage is doing lot of common rail diesels, they should have profesional tool set for that. Shouldn't be unheard repair method, and needs no head off.

Yes nozzle holder is common and cheap part, easy to swap when injector on table.

I'll check with the shop on that. I know they have an SDS or professional-level clone from prior experience.

 

[cowboyt]

That difference between the computer mpg and hand-calculated mpg also can result from changing the transmission conductor plate. Happened to me in the 2003 S430 (also 722.6 tranny) where the computer was optimistic for about a year, then it corrected and now reads within 2 or 3% of hand calculations.

With regard to Black Death, or leakage at the fuel injector port, yep, that’s fixable by the DIY’er if desired.

 

[tabijan]

Drifting from topic, a key source of error for hand calcs is variance in calling the tank full. Does it vary by an ounce or 10 ounces? This error averages out over more measurements, ideally more sequential measurements. Good basis for cost to operate.

Pulse width calcs should be accurate or the engine wouldn’t run properly. It’s just a lot more accurate instantaneously in a steady state than over the course of a trip because any error is summed (integrated?) through longer term measurements rather than averaged out. I think idling/zero speed throws off the measurement. Otherwise a good basis to estimate how hard the engine’s working. Under the same ambient conditions, you might compare instantaneous mpg at different “constant” speeds, different loads, different fuel blends…

Back to topic, how long does it take for Black Death to build? How frequently should the injector valley be inspected?

Sixto
05 E320 wagon 189K miles

 

[The Dark Side of Will]

Drifting from topic, a key source of error for hand calcs is variance in calling the tank full. Does it vary by an ounce or 10 ounces? This error averages out over more measurements, ideally more sequential measurements. Good basis for cost to operate.

My dash display is off by >30%... that's way more than fill-up error.

I guess how fast Black Death builds up depends on how bad the injector seal is leaking.

 

[cowboyt]

My dash display is off by >30%... that's way more than fill-up error.

I guess how fast Black Death builds up depends on how bad the injector seal is leaking.

Indeed. The S430 was off by 20%. You didn't change the conductor plate recently, perchance, did you?

 

[The Dark Side of Will]

Indeed. The S430 was off by 20%. You didn't change the conductor plate recently, perchance, did you?

I did not. It's been like this the entire time I've owned the car, covering 50k miles from 168k to 215k

 

[aeubank]

The whole issue I have had with mine is the leaking seals. So much so, I get them resealed like every 50k miles with new stretch bolts and seals. I have heard there was another diesel engine from Mitsubishi or something that has thicker longer-lasting seals in it and would work on the OM648.
This has been my experience and the injector seems to be fine. Now, removing it with all that goo on it and keeping it functional could be a challenge.

 

[mersum1es]

That Honda seal is kind of a snake oil thing... MB seal will do well enough if job done properly. Main problem is MB injector attaching done by only one bolt. Other brands use 2 bolts. True that after many refining, material is removed so thicker seal is needed. Less than mm drop can decrase you fuel spray filling in cylinder.