Subject boat/engine: 2005 24V with Marine Power 5.7 340HP Vortec MPI
I believe I have a failing fuel pump or pumps. I get an intermittent stalling issue that presents in different ways. I can be at cruising speed (3k RPM) and the engine stutters or sometimes it will idle normally and then stutter and stall and sometimes it will not start (it will crank and stumble then it appears to starve for fuel and die).
The issue is very intermittent, it can run perfectly for a few days then start to die but it is happening more frequently now. I am confident that it’s not a vapor lock issue as it’s not related to starting again after shutting the engine down hot.
When I turn the key on before starting I have noticed that there is a whining/chirping sound coming from either the high pressure or low pressure fuel pump. Listening up close I believe it’s the Gforce pump making the sound. When things are ok, the fuel pump makes a whirling sound but when it’s not running ok, the fuel pump makes a loud whine/chirping sound most noticeable when turning the key on for priming the fuel rail.
Because the issue is intermittent and I don’t have an easy way to check fuel pressure at the fuel rail when the problem arises, I am looking at just replacing the pump or pumps.
So my question is, should I just replace the high pressure GForce pump that sounds like the culprit or should I replace both the high pressure and low pressure pump together? Is there a way to tell which one is the problem?
Does anyone have part numbers for the gforce high pressure pump and the low pressure pump?
Do I need to replace the entire gforce unit or can the upper portion be serviced with a new pump and the canister/filter housing stays in place?
I am far from an engine expert, so this is based on online research, limited experience and logic, so please chime in if you think I’m going down the wrong path.
Other info: The gforce filter is new this spring and this engine does not have an inline fuel filter between the gas tank and the low pressure fuel pump unless I have overlooked it somehow.
I believe I have a failing fuel pump or pumps. I get an intermittent stalling issue that presents in different ways. I can be at cruising speed (3k RPM) and the engine stutters or sometimes it will idle normally and then stutter and stall and sometimes it will not start (it will crank and stumble then it appears to starve for fuel and die).
The issue is very intermittent, it can run perfectly for a few days then start to die but it is happening more frequently now. I am confident that it’s not a vapor lock issue as it’s not related to starting again after shutting the engine down hot.
When I turn the key on before starting I have noticed that there is a whining/chirping sound coming from either the high pressure or low pressure fuel pump. Listening up close I believe it’s the Gforce pump making the sound. When things are ok, the fuel pump makes a whirling sound but when it’s not running ok, the fuel pump makes a loud whine/chirping sound most noticeable when turning the key on for priming the fuel rail.
Because the issue is intermittent and I don’t have an easy way to check fuel pressure at the fuel rail when the problem arises, I am looking at just replacing the pump or pumps.
So my question is, should I just replace the high pressure GForce pump that sounds like the culprit or should I replace both the high pressure and low pressure pump together? Is there a way to tell which one is the problem?
Does anyone have part numbers for the gforce high pressure pump and the low pressure pump?
Do I need to replace the entire gforce unit or can the upper portion be serviced with a new pump and the canister/filter housing stays in place?
I am far from an engine expert, so this is based on online research, limited experience and logic, so please chime in if you think I’m going down the wrong path.
Other info: The gforce filter is new this spring and this engine does not have an inline fuel filter between the gas tank and the low pressure fuel pump unless I have overlooked it somehow.
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