On my 05, when started cold, or hot, it has a miss for a few seconds then smooths out. Once it does smooth out, it still sometimes has a somewhat uneven idle. I would not call it a miss, and is sometimes felt more than other times. I know for sure I have an injector that is seeping a little as I had some diesel spill from removing the return lines, which was pooled at the base of the injectors and I got bubbles out of #3. I plan on pulling it and replacing the seals. I have also gone into SDS and looked at the smooth running screen, or whatever it is called. Is this similar to balance rates on a Duramax where if you have them go above a certain number they need to be replaced? See attached screen shot. #1 is way higher than the rest? Does this indicate the injector is bad? I should probably do a return rate test (I have the factory tester for this). If this is indicating an issue with any of the injectors, can the nozzles be replaced, or does the entire injector need to be replaced?

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You defiantly need to take care of fuel leaks and or any air getting sucked into the system.

OK so I only know about trouble shooting mechanical injection systems. I don't know how you can safely shut off the fuel to single injectors on an OM648 or if it is going to cause some nagging computer code issues.

To find the bad injector you essentially shut off the fuel to one injector at a time and note the effect of what happens when that injector not functioning. Besides listening and feeling the effect you can watch the tachometer.

Shutting off the fuel to a good injector should show have an obvious effect. Shutting off the fuel will have less of a bad effect or no effect. If this happens you have actually only located a problematic cylinder, but you suspect the injector.

To find out if it is really the injector you would mark the suspect injector and remove it and remove a good injector and swap positions.

You redo the test. If the problem follows the suspected injector to the new cylinder, it is likely an injector problem.

If the problem is still with the old cylinder, you have something going on inside of the cylinder and need to do compression or leak back tests to determine if there is something causing a compression leak like a burnt or poorly seating valve or a head gasket leak.

OM648 Injector Refurbish | Changing the Nozzles!

https://www.youtube.com/watch?v=ku7iaattRD0

https://www.benzworld.org/threads/om648-cdi-injector-rebuild-diy-guide-changing-the-nozzles.2906602/

Note I did not completely look at or read the sites I posted.

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84 300D, 82 Volvo 244Gl Diesel

Make sure there are no Black Death issues as well.

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

Full disclosure - everything I'm about to say is pure conjecture. I have no formal training or knowledge of the CDI injector diagnostics.

The screen you've posted appears under the adaptations sub-menus in the Star Diagnostic system and I think it's showing you the system-generated correction adaptation factors based upon it's evaluation of the running conditions of the engine.

I think there is a base map in the CDI control unit that has the theoretical injection quantity amounts for various running conditions and the ECU has learned, over time , that it needs to add or subtract a certain amount of fuel from the base maps to ensure smooth running. The ECU can determine this by looking at the injector pulse timing period and comparing the amount of fuel injected to the rotation of the engine based on the crank position sensor.

In short it knows how much fuel has been injected, or at least it thinks should have been injected, and how much crank rotation was produced from that quantity of fuel and combustion.

Since each injector will have individual characteristics each injector has its own adaptation value that the ECU will use to fine-tune fuel delivery to each specific injector. I think negative values indicate a reduction in base map fuel delivery and a positive value is an increase in base map volume.

I don't know what the Hub designation is but the cubic mm designation is clearly a volume specification and a cubic MM is a mighty small amount of volume.

Your screen also pretty clearly states that if an individual injector gets to >5mm/Hub it should be replaced.

It would appear that most of your injectors have a negative adaptation which would indicate a reduction in fuel for that injector maybe to compensate for wear resulting from larger injection orifices? #1 has a large positive value which might mean it's partially plugged and the ECU is boosting fuel into that injector to compensate?

It should also be noted that each injector has a 6 digit code that must be entered into the CDI control unit. I believe this 6 digit code is used to describe general attributes of the injector so that fine tuning can be more accurate.

You can enter the injector codes and associate them with each cylinder in another menu item under the adaptation menu.

Hopefully a dealer-tech that's actually been trained on this issue will see this and confirm or deny my guesswork!!

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98 Dodge-Cummins pickup (123k)
13 GLK250 (135k)
06 E320CDI (323K)
16 C300 (62K)
82 300GD Gelaendewagen (54K)

Your guesswork is correct. Basically #1 needs to be replaced and I have a replacement on the way. I was also debating on if all of them should just be replaced since the car as 343k miles on it. I am going to replace the one for now and see how it goes. Car does NOT have any black death although probably did in the past.