Suzu 2015 115A

[yann83]

Hi,

I am having problem with my engine, a Suzuki 2015 115a with 1100 hrs, all services done.

The problem is that randomly the engine drop 1000 to more than 2000 rpm or more. Doesn't matter if I am divining slow or at full speed.
The problem occur very randomly, also can disappear for a day and come back.
No Alarms or errors
sometime at idle is struggling just a bit
There is nothing that is triggering the drop of rpm
Sparks were bit hot color

Now it several months we are trying with Official Suzuki Mechanic to solve the issue.

Here what we changed and tested

- Used a external fuel tank
- Changed fuel line form tank to engine (hoses, water separator, connector)
- Changed mechanical pump
- inspected and cleaned VST (changed filters, pin, fuel pressure regulator)
- Serviced the engine (filters, oils, sparks etc...)
- Tested connecting the pc to the engine
- Fuel pressure test at the rail
- Tested with new coils
- tested with new Injectors
- Tested with new electric harness
***We tested with another ECU (from same model and year, same code, the ECU is from my neighbor boat) and problem did not show up BUT we tested only few hours as we did not had time.
My ECU had some oxidation on 2 pin (grey color), we polish that and cleaned with electric cleaner, the issues still persist.

Any input is appreciate

[redlowrey]

When the revs drop down does the engine still run smooth, or does it run rough when the revs drop down, and does it stall, when you changed the coils did you use the leads that came with the coils or your leads.
Just to make sure that your ecu is in control disconnect the temp sensor and turn the key on and see if it flashes a code for it.

From what you are describing it sounds like a fuel problem, I can't see if you changed the high pressure pump, testing the fuel pressure does not mean that that there is nothing wrong in the fuel pump circuit.
Because the problem is intermittent the pressure could have been alright at the time of testing.