burtonrider11
Petty Officer 2nd Class
- Joined
- Jul 28, 2005
- Messages
- 178
2000 454 MAG MPI - MEFI3, Cool Fuel,
Serial #0L611921
Approximately 530 hours
Bought the boat last fall. Ran well, but I felt there was more in her. Previous owner didn't really have much service history either. So in the offseason I did the following and noted a few things:
Cleaned flame arrestor - was CAKED with grime
New Plugs - Not fouled but an indication of running rich, figured flame arrestor issue
New wires, cap, rotor, ignition coil, ignition module - double and triple checked to make sure wires are correct.
New water/fuel seperator
Pulled intake plenum, cleaned TB and plenum, new intake gaskets, cleaned any hoses.
Fresh Rec Gas this spring - last fall we used only rec gas, no ethanol and treated it with stabil.
CLeared cooling hoses and found a few obstructions.
Fresh oil change and filter - double checked to make sure it isn't overfilled.
NEW flow matched injectors with an ECM re-program to match. The re-program was done by a highly recommended and reputable engine builder. He has been extremely helpful as well.
So this spring, put it all together and went to start it. I had purged the fuel rail of air from Shrader valve. Took awhile to get started. When it did, it didn't want to idle real well. Any blip of the throttle would cause hesitation and then rev up. Upon decel it would nearly stall.
A few days of this and troubleshooting yielded no results. We took the boat to engine builder and together with scanner found a bad ECT harness. He also double and triple checked his fuel mapping. Replaced the ECT harness and with scanner found that the ECT was now reading. I also replaced the plugs at the recommendation of engine builder as they were likely fouled - they were.
Fast forward to yesterday, tried running, it runs better, but still hesitates and struggles to idle. I do have scan software and logged the data. I spoke with the engine builder on the phone, who went thru the numbers. MAP might be a *little* high, but it wasn't out of spec. TPS reads correctly, I can see IAC moving as the engine warms.
The only thing I have not checked is fuel pressure, I'll do that today. In doing some reading on this and other forums, it appears that a clogged return line or bad regulator can lead to increased fuel pressure and perhaps a rich condition.
Last thing to note, when I pull the vacuum line off the intake manifold, I see/hear no difference in RPM and engine response.
I have all the data from the engine scanner if that would be helpful. I will be getting a fuel pressure gauge and vacuum gauge to test that as well. I am open to any suggestions that anyone has! It's almost getting warm here in Michigan, it's going to kill me if I can't get this fixed lol.
EDIT: Timing has been set and is verified at 8 degrees BFTDC.
Serial #0L611921
Approximately 530 hours
Bought the boat last fall. Ran well, but I felt there was more in her. Previous owner didn't really have much service history either. So in the offseason I did the following and noted a few things:
Cleaned flame arrestor - was CAKED with grime
New Plugs - Not fouled but an indication of running rich, figured flame arrestor issue
New wires, cap, rotor, ignition coil, ignition module - double and triple checked to make sure wires are correct.
New water/fuel seperator
Pulled intake plenum, cleaned TB and plenum, new intake gaskets, cleaned any hoses.
Fresh Rec Gas this spring - last fall we used only rec gas, no ethanol and treated it with stabil.
CLeared cooling hoses and found a few obstructions.
Fresh oil change and filter - double checked to make sure it isn't overfilled.
NEW flow matched injectors with an ECM re-program to match. The re-program was done by a highly recommended and reputable engine builder. He has been extremely helpful as well.
So this spring, put it all together and went to start it. I had purged the fuel rail of air from Shrader valve. Took awhile to get started. When it did, it didn't want to idle real well. Any blip of the throttle would cause hesitation and then rev up. Upon decel it would nearly stall.
A few days of this and troubleshooting yielded no results. We took the boat to engine builder and together with scanner found a bad ECT harness. He also double and triple checked his fuel mapping. Replaced the ECT harness and with scanner found that the ECT was now reading. I also replaced the plugs at the recommendation of engine builder as they were likely fouled - they were.
Fast forward to yesterday, tried running, it runs better, but still hesitates and struggles to idle. I do have scan software and logged the data. I spoke with the engine builder on the phone, who went thru the numbers. MAP might be a *little* high, but it wasn't out of spec. TPS reads correctly, I can see IAC moving as the engine warms.
The only thing I have not checked is fuel pressure, I'll do that today. In doing some reading on this and other forums, it appears that a clogged return line or bad regulator can lead to increased fuel pressure and perhaps a rich condition.
Last thing to note, when I pull the vacuum line off the intake manifold, I see/hear no difference in RPM and engine response.
I have all the data from the engine scanner if that would be helpful. I will be getting a fuel pressure gauge and vacuum gauge to test that as well. I am open to any suggestions that anyone has! It's almost getting warm here in Michigan, it's going to kill me if I can't get this fixed lol.
EDIT: Timing has been set and is verified at 8 degrees BFTDC.
