Unresolved problems with Cummins QSB 6.7 liter engine

[Fletcher500]

We have Hull #4, a 5 year old Helmsman 43 and I would not hesitate to enter into another new boat build contract tomorrow with the Helker’s. The boat, subsequent support from the Helker’s, and the QSB engine have all exceeded my expectations.

 

[sunchaser]

Hopefully they will do some fuel pressure and vacuum tests before changing parts. Knowing where and why issues are located could lead to a better resolution. A
Sensor issue may be lurking too thus the need for more than plug in diagnostic protocol testing.

Has construction debris in the tanks or fuel system been 100% eliminated?

 

[KnotYet]

I am sorry to hear about the issues, just bad all the way around. I know Shilshole and there is know way I'd want to be around that breakwater with a sketchy engine. Depending on wind and tide you could easily be in trouble in less than 60 seconds with a dead engine.

If the theory is that metal shavings made it to the high pressure pump, are they testing for any damage the shavings may have made past the high pressure pump? I don't know this engine but I am assuming the filter is before the pumps. Again not knowing the engine but it seems like the injector spray patterns and flow rates may need to be validated. Armchair mechanic here so take my comments with a grain of salt.

Other diesel engines, like VW's, have a history of this defect occurring also.
The repair always was replacement of all fuel components, including the tank(s).
This was due to the metal shavings being returned to the tank via the bypass.
It was the Bosch CP4 high pressure pump and resulted in a years-long court battle.

 

[DDW]

This is a pretty well known problem in the CP4 pump in Ford 6.7L diesels. The piezo injectors are very sensitive to debris. Ford even has a single PN "kit" for this possibility, which includes all the fuel components including the high pressure lines, as they cannot be reliably cleaned. Metal returned to the tank via the spill fuel, or from the crank case of the pump, you hope would be eliminated by the fuel filters, but they should still be cleaned.

The later model Cummins 6.7 also has the CP4 pump, there is a recall on Dodge trucks for this, and suppliers are also supplying a kit of components to replace nearly everything in the fuel system.

There is a company making a "disaster prevention kit" which keeps the metal from a failed CP4 pump from entering the fuel system, it might be something to consider if you have a 6.7 with the CP4 pump. There is also an aftermarket solution which allows retrofitting the CP3 pump to a Cummins 6.7 (the CP3 was considered more reliable).

 

[sunchaser]

DDW
I just looked up the failure modes in the 6.7 for cams and pistons caused by a failure of the CP4 pump. Scary stuff including Ram recalling 220,000 6.7 diesel pickups.

It gives me pause in agreeing that the OPs engine problems can be 100% resolved by Cummins. Cummins should put forth a written plan plus discuss in writing the 4 vs 3 pump apparent fiasco.

 

[Fletcher500]

There are known problems with the fuel transfer pump on the Cummins engines used in truck diesels such as the Dodge truck. Cummins does not supply the fuel supply pumps and other ancillary items to the truck dealers, and they can use what they want.

There are currently NO open campaign's on the fuel transfer pump for the 6.7 marine diesel on the Cummins Quick Serve website, and I confirmed that fact today with Cummins.

I spoke to the authorized Cummins service department in my area and they handle a very large amount of 6.7’s for both recreational, Naval, and commercial boats. BTW, the Navy’s first choice for a replacement of a tired engine is the 6.7 and that includes fast boats used by Seals who have a lot riding on a reliable engine. There are thousands of these engines out there and they are known workhorses. In addition to having no open Campaigns on the fuel transfer pump as I previously stated, Cummins stated they have not seen any unusual issues related to the fuel pump on the marine 6.7.

Post #65: Ready - Shoot - AIM.

With that said, engines sometimes have bad parts and it can be a process to figure it out. No fun for everyone, but part of the deal of boat ownership.

 

[twistedtree]

There are known problems with the fuel transfer pump on the Cummins engines used in truck diesels such as the Dodge truck. Cummins does not supply the fuel supply pumps and other ancillary items to the truck dealers, and they can use what they want.

There are currently NO open campaign's on the fuel transfer pump for the 6.7 marine diesel on the Cummins Quick Serve website, and I confirmed that fact today with Cummins.

I spoke to the authorized Cummins service department in my area and they handle a very large amount of 6.7’s for both recreational, Naval, and commercial boats. BTW, the Navy’s first choice for a replacement of a tired engine is the 6.7 and that includes fast boats used by Seals who have a lot riding on a reliable engine. There are thousands of these engines out there and they are known workhorses. In addition to having no open Campaigns on the fuel transfer pump as I previously stated, Cummins stated they have not seen any unusual issues related to the fuel pump on the marine 6.7.

Post #65: Ready - Shoot - AIM.

With that said, engines sometimes have bad parts and it can be a process to figure it out. No fun for everyone, but part of the deal of boat ownership.

I agree that without knowing the pump used on the marine 6.7, you really can't draw any parallels.


And I agree that shite does happen and needs to be dealt with, and some problems require a lot of pressure and persistence to get resolved. It's just how it is.

 

[DDW]

DDW
I just looked up the failure modes in the 6.7 for cams and pistons caused by a failure of the CP4 pump. Scary stuff including Ram recalling 220,000 6.7 diesel pickups.

It gives me pause in agreeing that the OPs engine problems can be 100% resolved by Cummins. Cummins should put forth a written plan plus discuss in writing the 4 vs 3 pump apparent fiasco.

The CP4 pump failures have been extensively investigated by the Ford pickup aftermarket suppliers. The problem with the pump design is that first fuel is delivered to the pump crankcase (cam case, actually) for lubrication, then it goes into the top end where the pressure is increased to about 30,000 psi, then to the common rail and pressure regulator. If there is any problem with the cam and pistons, the detritus from it finds its way into the top of the pump and then the whole fuel system - lines, regulator, and injectors. The solution people have developed is to return the fuel used as a lubricant from the cam case back to the fuel tank rather than into the common rail. This will contaminate the fuel tank, but not the fuel system. The latest version of these systems has another fuel filter on the fuel returned to the tank, so it doesn't get contaminated either.

It isn't a problem affecting a huge percentage, but enough that Ford (and Dodge) have kits of parts to address the damage, and aftermarket vendors are supplying solutions. There is a pretty good explanation along with a video documenting the failure and solution here. Cummins only started using the CP4 pump recently, Ford has been using it since 2015.

 

[Doug_Snider]

Today, the Cummins tech who made the three previous visits returned and replaced the gear pump, lift pump and on engine filter. A sea trial that followed included frequent runs at WOT and showed no recurrence of any of the reported symptoms. We will be taking it out tomorrow on a day cruise. We will be recording speed and fuel flow at specific RPM readings and noting any irregularities if they occur.

We thank Scott Helker for putting some pressure on Cummins and the Cummins Marine Division Western Manager for seeing that the repair was promptly carried out. We also thank Van Helker for the time he spent on the boat ruling out tank contamination as a possible cause and taking the boat out for today’s apparently successful sea trial. Our summer may have been salvaged yet.

 

[catalinajack]

The CP4 pump failures have been extensively investigated by the Ford pickup aftermarket suppliers. The problem with the pump design is that first fuel is delivered to the pump crankcase (cam case, actually) for lubrication, then it goes into the top end where the pressure is increased to about 30,000 psi, then to the common rail and pressure regulator. If there is any problem with the cam and pistons, the detritus from it finds its way into the top of the pump and then the whole fuel system - lines, regulator, and injectors. The solution people have developed is to return the fuel used as a lubricant from the cam case back to the fuel tank rather than into the common rail. This will contaminate the fuel tank, but not the fuel system. The latest version of these systems has another fuel filter on the fuel returned to the tank, so it doesn't get contaminated either.



It isn't a problem affecting a huge percentage, but enough that Ford (and Dodge) have kits of parts to address the damage, and aftermarket vendors are supplying solutions. There is a pretty good explanation along with a video documenting the failure and solution here. Cummins only started using the CP4 pump recently, Ford has been using it since 2015.

Add in Chevy Duramax having had the same problems with the CP4. When a CP4 blows up on Chevys, the repair is a complete replacement of the fuel system, pump, fuel lines, and fuel tank at a cost of around $14,000. Chevy no longer uses the CP4 on their Duramax engines. I own a 2003 model with a CP3 pump, with 340,000 miles and 8,400 hours on the clock, all original including the turbo.

 

[chanprr]

Today, the Cummins tech who made the three previous visits returned and replaced the gear pump, lift pump and on engine filter. A sea trial that followed included frequent runs at WOT and showed no recurrence of any of the reported symptoms. We will be taking it out tomorrow on a day cruise. We will be recording speed and fuel flow at specific RPM readings and noting any irregularities if they occur.

We thank Scott Helker for putting some pressure on Cummins and the Cummins Marine Division Western Manager for seeing that the repair was promptly carried out. We also thank Van Helker for the time he spent on the boat ruling out tank contamination as a possible cause and taking the boat out for today’s apparently successful sea trial. Our summer may have been salvaged yet.

Good news Doug! Looks like the new pumps and filter have solved the problem. Enjoy your time on the water!!

 

[MYTraveler]

We thought a brand new boat would not come with problems but we were wrong.

In my personal and vicarious experience, new boats with complicated systems always have some bugs to be worked out. Mine did, though nothing as frustrating as yours. In retrospect, the mistake I made was to accept delivery before all commissioning work was complete and the boat had passed a comprehensive sea trial in which every system was demonstrated to be working correctly. And that should be coupled with contract provisions that incentivize the builder to deliver on time. I also lacked that, thinking that tight space in the yard and the final payment would be sufficient. Those went out the window when I accepted delivery with known problems. The boat was later than expected and I was overly anxious to begin using it. In your case, it seems that a pre-acceptance sea trial in which WOT was tested would have revealed the problem.

 

[DDW]

Add in Chevy Duramax having had the same problems with the CP4. When a CP4 blows up on Chevys, the repair is a complete replacement of the fuel system, pump, fuel lines, and fuel tank at a cost of around $14,000. Chevy no longer uses the CP4 on their Duramax engines. I own a 2003 model with a CP3 pump, with 340,000 miles and 8,400 hours on the clock, all original including the turbo.

It's about the same expense on a Ford diesel. The kit of parts is around $4-5K (mostly the new CP4 pump and injectors), a fair amount of labor in addition. On the Cummins, there is the possibility of retrofitting the CP3 pump. That is a $2700 proposition plus installation. Of course Cummins will attempt to void the warrantee if you do that. But it is a concern on a boat, if you are taking it to remote places, even if it is a 1% problem. The '"disaster prevention" kit is only about $400 plus installation.

I have a Ford diesel pickup, only about 40K miles and keeping my fingers crossed.

 

[ABfish]

Add in Chevy Duramax having had the same problems with the CP4. When a CP4 blows up on Chevys, the repair is a complete replacement of the fuel system, pump, fuel lines, and fuel tank at a cost of around $14,000. Chevy no longer uses the CP4 on their Duramax engines. I own a 2003 model with a CP3 pump, with 340,000 miles and 8,400 hours on the clock, all original including the turbo.

I had a 2003 Duramax that went 210K miles with no major issues, not even injector replacement. Then the CP4 went out, $10K estimate at the dealer, I didn't believe it, paid an independent mech to draw the same conclusions.

Thus ended my light truck diesel experiment. I still have one in my company fleet, a 6.7L Ford that's been good for 70K miles thus far.

 

[DDW]

You may want to consider the CP4 mod from S&S for the Ford. Cheap insurance, and they've proven that it works. I'm going to put one on mine as soon as the warrantee has expired.

 

[chanprr]

Our H46 is hull#1 of the series. The vessel is hand built and I am hoping that any issue on delivery would be a minor one. Our H38E was top quality, excellent fit and finish and well built. We had no problems which prevented cruising immediately after commissioning at the Helmsman's docks in lake Union WA. The H38E was hull#40 so the factory crews were well experienced in the model build by then. Doug's 38E is an excellent vessel, and the engine issue is a Cummins build problem not a Helmsman one. Van and I work constantly on the 46 build and have every confidence that he, Scott, and their factory manager will make every effort so that the new Kiskadee will be a top class build in quality, fit and finish. By the way, I selected a John Deere 6090SFM85 engine.

 

[twistedtree]

In my personal and vicarious experience, new boats with complicated systems always have some bugs to be worked out. Mine did, though nothing as frustrating as yours. In retrospect, the mistake I made was to accept delivery before all commissioning work was complete and the boat had passed a comprehensive sea trial in which every system was demonstrated to be working correctly. And that should be coupled with contract provisions that incentivize the builder to deliver on time. I also lacked that, thinking that tight space in the yard and the final payment would be sufficient. Those went out the window when I accepted delivery with known problems. The boat was later than expected and I was overly anxious to begin using it. In your case, it seems that a pre-acceptance sea trial in which WOT was tested would have revealed the problem.

I received advice along the same lines when I built my first boat, and its the best advice I got. I mostly paid attention to it on the first build, but finally just closed and left because I was so frustrated. I think that's probably typical since you are always antsy to get moving.


A few years in I was reading through my maintenance log which for me is basically a diary of everything I have done on the boat, and every issue I have observed. Looking back, all the problems that I had with the boat post-delivery were visible during commissioning and just weren't carefully investigated at the time.



The second time around I really stuck to it, and very thoroughly tested EVERYTHING personally. The time spent was well worth it.

 

[Tom-Jill-Lilly]

Our H46 is hull#1 of the series. The vessel is hand built and I am hoping that any issue on delivery would be a minor one. Our H38E was top quality, excellent fit and finish and well built. We had no problems which prevented cruising immediately after commissioning at the Helmsman's docks in lake Union WA. The H38E was hull#40 so the factory crews were well experienced in the model build by then. Doug's 38E is an excellent vessel, and the engine issue is a Cummins build problem not a Helmsman one. Van and I work constantly on the 46 build and have every confidence that he, Scott, and their factory manager will make every effort so that the new Kiskadee will be a top class build in quality, fit and finish. By the way, I selected a John Deere 6090SFM85 engine.

I agree with Chanprr X 3, this was a Cummins issue.

I have not been reading this string, but Ive been in touch with Doug via email, texts over the past weeks.

After reading this, I now got reminded to worry about my CP4 fuel pump in my 2016 GMC Duramax. Need something to think about while cruising the inside passage this summer.

Doug, I hope they (Cummins) will identify what the issue was and its smooth sailing from here. Will be in touch.

 

[RedRascal]

Today, the Cummins tech who made the three previous visits returned and replaced the gear pump, lift pump and on engine filter. A sea trial that followed included frequent runs at WOT and showed no recurrence of any of the reported symptoms. We will be taking it out tomorrow on a day cruise. We will be recording speed and fuel flow at specific RPM readings and noting any irregularities if they occur.

Did Cummins seem to be concerned about any damage or issues downstream of the injector pump? It may seem to be running fine but I would want proof that all injectors are spraying at factory spec. Glad you're making headway on getting it sorted out, that must be a relief to be making headway.

 

[sunchaser]

By the way, I selected a John Deere 6090SFM85 engine.

Is there a price difference from a Cummins?

 

[chanprr]

Is there a price difference from a Cummins?

Not that it mattered at the time. The JD was substituted for the Cummins because of build schedule, early 2023. There was no change in the overall cost in the PO. However, I recall that the listed price for the Cummins was slightly higher than the JD for similar HP rating back then.

 

[Delta Riverat]

Great to hear you got your boat fixed!

 

[Hippocampus]

Congratulations

 

[twistedtree]

Soooo, how was the first day out? Did it work OK? We all have our fingers crossed.

 

[Comodave]

Soooo, how was the first day out? Did it work OK? We all have our fingers crossed.

Yup.

 

[Doug_Snider]

We just returned from a long day trip. We ran the engine at several RPM ranges with none of the occasional RPM drops and none of warnings or shutdowns we had been experiencing. It felt like we were running a different boat. We recorded speed and fuel flow at each 200 RPM increment. The readings were consistent. Engine RPM was steady at every speed we tried. We now have confidence in the engine and are ready for our summer to finally begin.

 

[twistedtree]

We just returned from a long day trip. We ran the engine at several RPM ranges with none of the occasional RPM drops and none of warnings or shutdowns we had been experiencing. It felt like we were running a different boat. We recorded speed and fuel flow at each 200 RPM increment. The readings were consistent. Engine RPM was steady at every speed we tried. We now have confidence in the engine and are ready for our summer to finally begin.

That's such great news. Enjoy, after all your hard work.

 

[Comodave]

Good for you!

 

[chanprr]

We just returned from a long day trip. We ran the engine at several RPM ranges with none of the occasional RPM drops and none of warnings or shutdowns we had been experiencing. It felt like we were running a different boat. We recorded speed and fuel flow at each 200 RPM increment. The readings were consistent. Engine RPM was steady at every speed we tried. We now have confidence in the engine and are ready for our summer to finally begin.

Excellent news. Thanks for the updates. Fair winds and following seas.

 

[Nick14]

We just returned from a long day trip. We ran the engine at several RPM ranges with none of the occasional RPM drops and none of warnings or shutdowns we had been experiencing. It felt like we were running a different boat. We recorded speed and fuel flow at each 200 RPM increment. The readings were consistent. Engine RPM was steady at every speed we tried. We now have confidence in the engine and are ready for our summer to finally begin.

Happy news and great to hear!

So it may have been a mechanical and not electronic issue after all? My bet was on a sensor.

Now you can enjoy the beautiful boat!