Hi dhays,
did you find what caused the rough running your QSB? I have the same engine, and therefore interested to learn new things and Cummins.
Did you ever sort your rough running QSB?
Update, short version:
I called the local diesel shop and scheduled a mechanic to come out and look. Short version, they think it is a faulty lift pump. A new one is scheduled to be installed next Friday.
Longer version:
The mechanic hooked up the laptop to the ECM and the only codes it was throwing were for a fault in the lift pump. Since I know nothing about diesel engines, all I knew was that the engine was running rough and sounded terrible, he said is was a "fuel knock". On Friday, after a few minutes it would smooth out and idle quite nicely with only the very occasionally hiccup. However until then it sounded horrible. The kid said that he had a new lift pump sitting on his bench at the shop waiting to go into the exact same engine as I have.
Anyway, it was the only thing he could find from the ECM and he checked all the connections I had been concerned about and said they were all fine. He actually said they all look in new condition. Hopefully, this is the answer and it will fix the problem.
Longer rant version:
Tacoma Diesel has been the go-to shop for marine diesel work in the the Tacoma/Pierce County area for a long time. They are a Cummins certified shop as well as a certified shop for a bunch of other brands. I called them and spoke to Kurt the service scheduler and made an appointment for this last Friday. BTW, it took two calls to get the appointment made. The first time Kurt said that they had a lot of jobs in and that I should call back later in the week to see if they could schedule an appointment. This was a few weeks ago. Anyway the mechanic was going to be at the marina at 9:00am. I was there and ready by 8:30am.
At 9:40 I called Tacoma Diesel since no mechanic showed up. I spoke again to Kurt. Turns out Kurt had sent the mechanic scheduled to check out my boat away on an emergency commercial job. He forgot about me and didn't call. He apologized. What he didn't do was provide a solution. I told him that I was not happy and asked how he was going to solve his problem of forgetting a service appointment that he had on his own calendar. He finally agreed to find someone to send out and found someone while I was holding on the line. He would send them right out. He called back about 15 minutes later and said that the mechanic he was sending had to go pickup one of the shops laptops at another job. It would be another hour.
So at 11:00 the mechanic shows up. It turns out it was the same kid that showed up last year to remove my aftercooler for servicing. Almost the same thing happened last year. I had mad an appointment with Kurt for the job. Last year I called the day before to confirm only to have Kurt tell me that the experience mechanic who was to work on my boat he had just sent to AK on a commercial job the day before. I now think that he would have forgotten about me if I hadn't called him first last year. The kid he sent had been working with them for all of two weeks.
So the kid, now a year more experienced, seemed more familiar with my engine than he had last year. While he seems very competent, and I like the guy, he doesn't have the level of familiarity with the Cummins line that I would like. He does have some great backup however at Tacoma Diesel and did call a seasoned mechanic a couple times to kick around some ideas. Turns out this kid had worked on my slip neighbors boat a couple weeks ago.
Anyway, last year I let the scheduling issue go as a simple mistake that can happen in any business. I own a business and I know how things can happen at times. However, I have had the same experience now 2 our of 2 times. Not a good track record. I get the impression that Tacoma Diesel is focusing its service work on the commercial sector and large yachts and have less interest in the pleasure boat side of the service business.
So I will likely send the owner and email. I know him and think I owe him that much, but I am going to be looking for another shop to handle my repair and service needs. If anyone has some recommendations in the Tacoma/Pierce County area, I would appreciate it.