Ok im still trouble shooting my motor cutting out and curious to hear from anyone who has had issues with or knows the symptoms and how to check a few things? Ignition sensor in the distributer, tps, ignition coil, or fuel pumps. I ran the boat today with a fuel pressure tester and scanner and when it randomly dies I don't really loose any fuel pressure. Once it dropped about 5psi for a split second and that's it. When runnnig it stays at about 40psi and drops to about 32to 35psi. Question is if it were fuel pumps wouldn't the fuel pressure drop dramatically and wouldn't the boat studder and starve for fuel not just cut out and die or cutout for a second and then come right back. Any feedback would be great houseboat trip next weekend.
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Correct, when the fuel pressure goes too high (like over 60psi due to regulator) the injectors can't hold back the pressure and will flood the motor and shut it off. If the fuel pressure drops below 10psi there isn't enough pressure to atomize it through the injector correctly and you get the same result. Thus, your issue is spark related. The following is a response to your requested list of failures:
- Ignition sensor does all kinds of weird things from no start to backfiring at high speed to cutting out randomly.
- Ignition coil will show very light spark with the spark checker between the coil and the distributor but is most commonly associated with a no start condition followed by a "sneeze" if you will through the throttle body. Mercruiser is on backorder for them till the end of the month.
- TPS generally shows an inability to return to correct idle speed and will remain high up to about 2200 rpm until shut off and restarted.
- Fuel pump with low pressure is considered a failure but fuel pumps with high pressure mean the fuel pressure regulator needs to be replaced.
If it's running and randomly cutting out, ignition sensor would be my call to do first: it doesn't show on the scanner and like I stated before, presents with many different symptoms.Fixing everyone elses boat just so I can use mine... -
So it sounds like I should replace the ignition sensor first. That is good to hear that it doesn't show up on the scanner but why does the fuel pump circuit keep showing up? When I last checked it had stored it 32 times? And yesterdays instances were in check with how many times it did it as it was at 24 before yesterday. Im going to go run it today and when it dies I will turn off the key and check the water fuel separator to see if it has fuel in it to determine if it is the boost pump? So im guessing there is no way to test the ignition sensor? Thank you so much for the help!!!Comment
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Im just up in the air if I should order the fuel pumps tomorrow for 750 bucks on a wimm and a scanner? Ugh!Comment
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Ok so I went back out today to try my water fuel separator idea and when it finally died I turned off the key and tried to unscrew the filter but couldnt really get it loose so instead I loosened the fitting that goes into the filter from the tank and as soon as I loosened it it begain to leak fuel so I don't think it is the boost pump. Just like you thought. But I figured it was the only other thing I could think of trying. So back at home I took the cap and rotor off and found the ignition sensor but Im comcerned that there is no connector attached to it and I don't see a loose one anywhere. Is this normal that there is nothing connected to it? I can't find anything in my manual that shows any plug connected to it? I was going to order one up tomorrow, can I get one from an auto parts store or are they marine specific?Originally posted by boatwakes View PostComment
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here is a pic.Comment
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Ok so I learned this morning from merc that my motor does not use that sensor in the distributor. What would your second choice be? Im going go go threw all the wiring again tonight when I get home but im out of ideas?Originally posted by boatwakes View PostComment
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