I have problem with my engine (mounted in a Bayliner 2855 -2002);
Symptom:
Engine don't start at idle throttle when warm and have been shut of for approx 3 minutes or more. When I give it full throttle it starts after 5 seconds of cranking. Have to rev it for a few seconds and when it runns fine. Both at idle and at different throttle levels.
Also it consumes around 50% more fuel than other identical boats with same engine.
When starting the engine from cold condition it starts within a few seconds of cranking at idle throttle and it runns perfect from the beginning.
This has been done so far:
1. Fault code check with a ScanTool. No active fault codes related to the motor control system.
2. New Engine Temperature Coolant sensor. There was an fault code in the history related to the engine coolant sensor, so I replaced that one. (the new one gave the same readings as the old one)
3. New Coolant Water Thermostat. Have changed the thermostat as I discovered with the ScanTool that the engine operating temperature was to low (140 F). With new thermostat it is about 165 F. This also fixed my problem with a little to high idle RPM (is now 600).
4. New IAC. Verified to work fine with the ScanTool.
5. The MAPT-sensor give the same pressure as the barometric pressure when the engine is shut off. So the pressure sensor seems to work. Also the temperature reading is the same a the ambiant temperature when the engine is cold.
6. The Throttle Position Sensor seems to work fine. Verified with the ScanTool that it indicate 0% at idle and 100% at full throttle. The number increased fine when moving the throttle handle from idle to full throttle.
7. Have checked the tubing between the throttle house to IAC to manifold. Replaced the tube between the IAC and the manifold. The old one seemed to be a little bit obstructed.
8. Checked if some of the fuel injectors where leaking by lifting the complete set of injectors and fuel rail up. None of the injectors where leaking.
9. The vacuum tube between the manifold and the fuel pressure regulator was worn out and loose at the manifold end. Have now secured it.
I am almost out of ideas. Have been thinking of the ignition system. But as the engine starts fine cold and warm when re-started withing 3 minutes. And also run fine when started at full throttle when warm. I can't think of any problem with the ignition system. Please let me know if I have missed anything here.
I am still on the fuel/air mix ratio track. My guess is it gets to much fuel compared to air during startup. Giving full throttle clear up the wet cylinders and it fires. That might be reasonable due to the fact that it consumes to much fuel during cruising (But of course that could be an other different problem).
Maybe it don't get enough fuel during startup?
What parameters are important for the ECM during the startup sequence?
My last idea is to check the fuel pressure. Maybe it is to high and therefore the engine gets to much fuel. I will try to get hold of a pressure meter and check that. Should the pressure be 43 PSI in the fuel rails at any time?
All ideas are welcome!
Thanks,
Symptom:
Engine don't start at idle throttle when warm and have been shut of for approx 3 minutes or more. When I give it full throttle it starts after 5 seconds of cranking. Have to rev it for a few seconds and when it runns fine. Both at idle and at different throttle levels.
Also it consumes around 50% more fuel than other identical boats with same engine.
When starting the engine from cold condition it starts within a few seconds of cranking at idle throttle and it runns perfect from the beginning.
This has been done so far:
1. Fault code check with a ScanTool. No active fault codes related to the motor control system.
2. New Engine Temperature Coolant sensor. There was an fault code in the history related to the engine coolant sensor, so I replaced that one. (the new one gave the same readings as the old one)
3. New Coolant Water Thermostat. Have changed the thermostat as I discovered with the ScanTool that the engine operating temperature was to low (140 F). With new thermostat it is about 165 F. This also fixed my problem with a little to high idle RPM (is now 600).
4. New IAC. Verified to work fine with the ScanTool.
5. The MAPT-sensor give the same pressure as the barometric pressure when the engine is shut off. So the pressure sensor seems to work. Also the temperature reading is the same a the ambiant temperature when the engine is cold.
6. The Throttle Position Sensor seems to work fine. Verified with the ScanTool that it indicate 0% at idle and 100% at full throttle. The number increased fine when moving the throttle handle from idle to full throttle.
7. Have checked the tubing between the throttle house to IAC to manifold. Replaced the tube between the IAC and the manifold. The old one seemed to be a little bit obstructed.
8. Checked if some of the fuel injectors where leaking by lifting the complete set of injectors and fuel rail up. None of the injectors where leaking.
9. The vacuum tube between the manifold and the fuel pressure regulator was worn out and loose at the manifold end. Have now secured it.
I am almost out of ideas. Have been thinking of the ignition system. But as the engine starts fine cold and warm when re-started withing 3 minutes. And also run fine when started at full throttle when warm. I can't think of any problem with the ignition system. Please let me know if I have missed anything here.
I am still on the fuel/air mix ratio track. My guess is it gets to much fuel compared to air during startup. Giving full throttle clear up the wet cylinders and it fires. That might be reasonable due to the fact that it consumes to much fuel during cruising (But of course that could be an other different problem).
Maybe it don't get enough fuel during startup?
What parameters are important for the ECM during the startup sequence?
My last idea is to check the fuel pressure. Maybe it is to high and therefore the engine gets to much fuel. I will try to get hold of a pressure meter and check that. Should the pressure be 43 PSI in the fuel rails at any time?
All ideas are welcome!
Thanks,