Fast Idle Problem Drive by Wire
I have a 2006 197TT. The boat has 270 hours on it. The Perfect Pass has been updated to Star Gazer.
During the past two weekends I have noticed that randomly my boat will idle at 1200 to 1500 RPMs. If you shut the boat off it will go back to 600 RPM when it is restarted. If you rev the boat in neutral it will still stay at the advanced idle. I have also noticed that when you start the boat it goes to the fast idle for 10 to 15 seconds at times and then slow down. It always had the fast idle but it was only for a few seconds and then would idle normaly. I had a mechanic attach to the ECM and we see that when this is happening the desired RPM is 600 but the actual is really 1200 or whatever it happens to be running at. These numbers are being read directly from the ECM. The Pedal and Throttle position sensors seem to be reading correctly at that time also. It happens whether PP is on or off so I don't think it is the PP. The only thing that looks wrong on the sensors is the Manifold Pressure shows negative 40. The mechanic does not know what is wrong and neither do I. Has anyone seen this problem before or do you have any ideas how to troubleshoot this? I am concerned that a Drive By Wire product is not listening to the programming and sensors and seems to have a mind of its own.
Thank you in advance for any advice.