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Rookie request: We recently bought a 2001 SAN 5.8 PCM and it was running great all weekend. Then suddenly the motor seemed to be starved for fuel. It cuts in and out. Not a hesitation, but for a second, it stops running then starts running again. It is worse when applying more throttle, which made me think about that fancy fuel filter thing these motors have. I am not sure when it was last replaced or cleaned. Is this likely my issue or should I be looking for a different fix? Please let me know. Also...if that is the problem, does anyone have a step by step instruction how to get the motor walls out of the boat so I can reach the thing? We used to have a direct drive..where all repair and maintenance seemed easier than this v-drive stuff. Thanks for helping this rookie out! Much appreciated!
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When you said it's worse when applying more throttle. Does that mean like, hard acceleration? If you slowly bring the boat up to speed does it run okay at speed? If you're having a fuel supply issue, it will be likely to show up any time you're demanding a lot of fuel. Ignition is more likely the source if you're only experiencing the issue under heavy load, such as hard acceleration.
Aside from changing the fuel filter for good preventative maintenance, one thing to consider is there is a little tiny piece of fuel line inside of the Fuel Control Cell (the large canister with a filter, and a pump in it) that can develop a tiny crack and cause run issues. What you're describing sounds more like ignition, though, if I'm reading it right.
Getting those panels out isn't too hard, it's just like a little puzzle. I think there are slight differences from year to year, though, so mine may be different from yours. -
functionoverfashion Thanks, for your help. To be more specific, even when at 22 mph, it will cut out every 10 seconds or so. Then, when you accelerate, then the cutting out is much more frequently. If you bring it up to speed slowly, it will still have the problem. This happened suddenly. the boat was running fine, then in one run, the "check engine" light came on and this started. Does that help?Comment
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Hard to diagnose something like this without hearing engine. Could be fuel related or inition. Is it carb engine?
Sounds like possible timing issue....or if it"happened suddenly", perhaps a small piece of debris got jammed in fuel supply system somewhere?
Since you just got boat, guess you do not know what type of maintenance the boat has gotten recently to know where to start?Comment
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In my experience, I've heard this issue being resolved by new fuel pump relay or ignition module. Check out the poor mans gt40 thread on correctcraftfan. Identifying proper fuel pressure would help, but it's probably hard to do since you would be undrerway while the issue occurs.Comment
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Thanks all. Infinity it is injected, not carb. glassywaters, how do I determine if it may be the fuel pump relay or the ignition module? can I replace either one of those? Sorry for so many questions. I'll stop with my endless questions, lest I annoy you all if I have not already. Thanks.Comment
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...also, I thought of one more thing. The Check Engine light is on (the big one at the top center of the dash). Would that indicate more of a problem with the fuel or the ignition system?Comment
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Since the light is on that is the biggest indicator of the problem. Sounds like it is going into Limp Home mode which cuts the fuel off over a certain rpm range usaully about 2000rpm ~20mph. This is to protect the engine when it detects the temperature is too high or oil pressure is too low (maybe knock sensor input as well. not sure). So you are either experiencing one of these issues, or its just a bad sensor giving a false reading. There are 2 sensors for each thing. One that sends the reading to the gauge, and another that acts as the alarm switch for the light and limp mode. Check you gauges when it happens. If you are around 160F and between 30-60psi thats normal which would mean its proabably a bad alarm sensor. Otherwise its an actual issue, and the engine is acting as it should.
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Jimboslice54 Thanks, it was not in the limp mode. I could go fast, but as I did so, the engine momentarily shutting off would be more frequent (like every 2 - 3 seconds). Once I throttled back, it would be must less frequent. All gauges were sitting normally. Temp a needle below 160. PSI good. Engine light on, however. If it were an automobile, I would say the car was starved for fuel...change the filter. That was my first reaction to the boat as well. Then I learned about the fancy dancy filter / pump function on the PCM motors. It's possible it's ignition, but I would not imagine why it would increase the number of shutting off as I asked for more fuel, and then come back less frequently when I pulled back. ....I overanalyze for sure... thanks to everyone trying to help me out. BTW, there is no OBDII (like in an auto) for this boat or motor, is there?Comment
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Chances are, the motor is starving for fuel. Change the fuel filter in the FCC and the in line filter between the tank and the FCC and this should solve your issue. If not then check the anti siphon valve on the tank, and the fuel pickup tube screen that drops down in the tank. These are a little more work which is why I suggest you yltake a stepped approach and deal with the easily accessible pieces first. Doesn’t sound like relays to me since your fuel pumps are running but the boat just bogs down as you try to pour on the gas.
Had a a similar problem and I replaced the in line filter with a Napa equivalent. Problem no longer exists.
KyleComment
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Still could be limp mode and a bad sensor intermittently putting it in and out of limp. Had a very similar issue. Could run a pass every thing was fine. Next one half way through the power would drop out, and just go back and forth. Turned out to be a bad oil pressure sensor. The light shouldn't turn on for a fuel issue.
Now, if you're convinced its not limp, you can put a pressure gauge on the shrater valve on the fuel rail to diagnose if it's fuel or ignition. If the pressure drops its fuel, if not its something else. I believe the ideal pressure for the GT40 is between 38-40psi (you can search the forum for the exact number)
Lastly, there is a Ford OBD 1, but I've never had any luck getting it to work. Its back by the fuel relays and ECM
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