QSC 500 Brainteaser - 559 low fuel pressure alarm

[ezwoo]

Its a long story......At approximately 380 hours Cummins serviced my engines in April. New filters, fluids, impellers, etc. They also did a software upgrade which they refer to as a recalibration. Immediately thereafter port engine would start and then die. Never happened prior. These engines have been fantastic the previous two years since purchase at 147 hours. This is a 2006 44 Sedan Bridge. It would take about 3 cycles of this to keep it running. This would occur intermittendly after start up only. Cummins came back multiple times and could find nothing wrong. Put about 30 hours on the engines when recently after start/die cycle at the dock got a "559 low fuel pressure" alarm on port engine at 1120 rpm upon leaving the dock. Went back to dock and changed primary fuel filter on port engine. It was clean so did not change secondary filter or starboard filter. Left the next morning. Port engine fired up and stayed running. Starboard engine started right up and then died. Took 3-4 tries to keep it running. Then got same alarm on starboard engine at 1120 rpms. Ran the boat 40 NM back to homeport at no higher than 1950 RPM. No alarm on port engine but starboard stayed on most of the trip. No noticeable degradation in engine performance on either engine. Upon return Cummins changed all fuel filters, scanned the engines, did pressure tests on fuel lines, reloaded calibration software and declared good to go. They could detect nothing out of the ordinary except the error code. I also had fuel drawn from both tanks and had it tested at a materials lab. All came back good with close attention to particulant size in the fuel. I had recently fueled twice in the last 30 days at a large volumn fuel dock. All fueling has been only done at large volumn fuel docks. Took the boat out yesterday and the engines fired right up with no stoppage after start up. Went to the fuel dock at low rpm. After filling the tanks started port engine and it died. Went through start/stop cycle about 3-4 times before it kept running. Got out into the harbor and took it up to 1120 rpm and "559 low fuel pressure" alarm went off on port engine (this fuel filter had 4 hours on it). No alarm this time on the starboard engine. Dropped down below 1120 rpm and the alarm stopped. Went back to 1120 and the alarm would come back on and stay on. Cummins has been responsive and continues to try to resolve this problem on both engines. Have any of you expeirenced anything like this? Any ideas?

 

[BonBini]

Trouble shooting a fuel supply problem on any diesel can be time consuming and frustrating when all your doing is changing filters and clearing codes.

In your case I feel a fuel pressure gauge could be a valuable instrument. ie).. Any diesel needs good fuel pressure all the time, even under load. Your engines may be running fine with marginal fuel pressure, marginal fuel pressure is an indication of a developing problem. Your low fuel pressure code triggers when fuel pressure has dropped to a default critical…Perhaps some type of monitor is available that can read engine data so you can keep an eye on things.

From the long sad story above; it now seems both engines are infected. A few simple checks might be: 1)cut open a fuel filter and look for it to be loaded with a black slimy film (dead alga). 2)Look over all low pressure fuel lines for loose fittings (sucking air).

jm 0.02

 

[Art]

Have you tried having Cummins reloading the old calibration?

I recently had both of my engines die on me, and unfortunately I don't have a completely satisfactory explanation. On Boatdiesel.con there have been reported instances of "stumble stalling" with the 480CE engines http://boatdiesel.com/Forums/index.cfm?CFAPP=3&Forum_ID=34&Thread_ID=41403 there are also reports of idle problems after calibration changes. When I spoke to my local Cummins support they claimed no knowledge of the phenomenon.

Good luck, I wish I had more for you, I know how frustrating it is when you don't have confidence in your engines

 

[ezwoo]

I have been told the old calibration cannot be reloaded. They did reload the new calibration in case there was corruption in the initial load. Cummins did check fuel pressure at the dock but saw no issue. We are going to sea trial next week with tech on board and diagnostic computer hooked up.

 

[douglee25]

Weird problem for sure.

Can you verify if the tank vents are open and clear? Could it be possible that the tanks could be pulling a vacuum?

Doug

 

[ezwoo]

I will check the tank vents. Not sure what would clog them though. I also checked out the Boatdiesel.com link and there could be the basis for a similar issue/fix there even though it is a different engine. I sent the link onto Cummins. Thanks guys for the input.

 

[Art]

I have been told the old calibration cannot be reloaded. They did reload the new calibration in case there was corruption in the initial load. Cummins did check fuel pressure at the dock but saw no issue. We are going to sea trial next week with tech on board and diagnostic computer hooked up.

Ez, Please keep us up-dated on your findings. I was going to update my calibration, but if is not reversible I am going to proceed cautiously.

Art

 

[ezwoo]

Update after sea trial with Cummins tech on board. All the diagnostic leads hooked up to the computer, etc. As you could have guessed, the boat ran flawlessly. No error codes on either engine. Ran it up to WOT and not a blip on performance. No start/stop problem after cold start. The previous three outings resulted in low fuel pressure codes twice on port and once on starboard engines. I guess the difference was the tech on board. I will always take him with me frommnow on. Go figure. If nothing else, I am getting a hell of an education on electronic diesels, fuels systems, pumps, filters, calibration software and start up sequences.

 

[douglee25]

Murphy's law!

 

[DrBanzai]

Hi All,
I just went through a similar issue with my 2006 sea ray 44DB. My issue was the port engine would give me a high fuel pressure warning at idle and then would be fine at between 100 and 1800 RPM. As soon as I went over 1900 RPM it would give me a low fuel pressure warning on the port motor. I had Cummins come out and check it out. Turns out there are several factors at play here. Being a computer controlled engine it has lots of sensors and actuators in the fuel system. There are three things to look at:
1. Requested Fuel Pressure (what the sensor tells the computer the fuel pressure should be)
2. Response (actuator setting) fuel pressure (What the Actuator is responding with)
3. Actual Fuel Pressure (just what it says)

You need the cummins computer set up to look at any of this. It shows all three of these settings while the engine is running. On my boat, at idle the requested fuel pressure was about 6,000 lbs but the actual pressure was about 9,000 (causing a high fuel pressure warning). Then we ran it up to 1800 RPM and the requested fuel pressure was about 18,000lbs but the actual pressure was 9,000lbs (causing a low fuel pressure warning). From this test we were able to surmise that there was a problem with the port fuel pressure actuator. I swapped the port and starboard actuators and the high fuel pressure at idle problem did move to the starboard engine. So, I bought a new actuator and installed it ($400). Boat now runs fine at idle on both engines so I though all was well. Went out for a nice trip and went to 2,000 RPM and the port motor started to sputter and I got a nice low fuel pressure warning. So we had fixed half the issue. There is another sensor on the high fuel pressure rail that monitors the rail pressure and reports back to the computer so that is my next target.

Since your problem is moving between engines I don't this my experience may help much; I just wanted to give you every chance to run it down buy helping you understand how the system works and where the trouble can occur. Perhaps you have water in your fuel that is under the diesel inthe tank and when you drive because of the boat angle change you are getting that into the system? This can be missed in a fuel sample as many times they are taken from the filters at rest and then you get clean fuel. Just a thought. Best of luck! Please post again so we can all learn from your research.
-RDM

 

[Robski97]

I feel ur pain. I had faulty fuel injectors that they ( cummins dealer ) couldnt detect. I had to show them a video of the RPM dropping. Until they observed it they couldnt help. Then once they did see it . They only replaced the one injector they thought was faulty. When problem presisted they changed another ONE injector. I said u know i read really bad things about these common rail motors when injectors stick open. ( mine were were sticking closed ) He said they can only replace the defective ones they they deem defective. Long story short they changed 2 more injectors ( total of 4 ) before the issue went away. I cant tell you how many visits it took. I wish u luck. At least u had a trouble code for them to see. They thought I was nuts.

Rob

 

[Marine Nut]

Your symptoms are 100% classic-Replace the low pressure electric fuel pump before you waste anymore time.. Worth under $160,,


WS

 

[ezwoo]

The boat has been running better than ever since the Cummins Tech put the diagnostics on as previously reported. I've probably put about 10 additional hours on the boat. The mystery continues as to what was wrong and if somone fixed something on the last visit.

 

[Hampton]

Great! ?