The head of quality control for Cummins came and gave a talk to my class today about quality control at Cummins, and how they'd managed to improve their processes and save a lot of money via their "6 Sigma" method. Afterwards, I went up to him and asked him if he knew anything about the fueling issues in the 600s. He said that the problem wasn't with the injectors, rather with the Bosch fuel pump. Of course, the fuel pump problems can then manifest themselves as bad injectors, but apparently the major problems they've been having (which he admitted to) were sourced from the fuel pump itself. My thought is that, depending on how the pump is failing, it could be that particles from the pump are getting into the injectors, so in the end it's really both that are screwing up. This would also explain cases where there is a small amount of time between failures. Injector gets replaced and either doesn't appear to solve the problem or does, but then the knock comes back shortly thereafter. He also said that for the most part, these trucks were working just fine, but he admitted the failure rate was much higher than normal.

Regardless, they are working on it and at the very least we should have a response from Cummins at some point on what the solution to these problems is. I'm thinking if I have any of these "injector" issues, I may just replace the fuel pump on a matter of principle with this knowledge. Then again, maybe once the problem is confirmed they'll make an announcement for a revised fuel pump, but a recall of that magnitude (cost wise) I see as highly unlikely.

 

Thanks for the info Ted!

 

I feel better putting Power Service and 2 stroke oil in my fuel for added lubricity. The extra $4.00 seems worth it to me. Only time will tell, if the additive and my 3 micron fuel filter make a difference.

 

Lubricity, lubricity. The injection pump really needs it with the pressure involved on the common rail. I have been experimenting between Power Service, Howes and with some lubrication added (non-detergent) really notice a difference in the sound and operation of the engine. Just my 2 cents.

For a fact, some of the refineries are not adding the proper amount of lubricity improvers and some climatized spec is way off and they need a wake up call. Took a couple of samples myself and 1 looked closer to gasoline than diesel. Dry stuff for a high pressure pump.

 

The fuel pump he is talking about is the CP3 injection pump. Which, unfortunately, is after the fuel filter.

 

Yup

 

So does anyone know where I can find a spin on 2-3 micron filter that will handle 26,000 - 28,000 psi ???? Autozone maybe!


Thanks for the info Tdupuis, very interesting and makes a lot of sense. It would seem there would be higher failure rates on CP3's and injectors with "pressure" boxes installed.

 

I dont think he knows what he is talking about. *relative to the issues with the 600 are more mileage related.

 

Think of this , putting in tighter fuel filters is makeing more resistance for the lift pumps to pull through, or push through whatever. Right ???????