stretch79

While running across the water at about 3-4k rpms the engine rpm's will drop out to 1k +/- and sometimes die completely, I get a quick beep when this happens and then it will fire right back up. Engine idles great, has plenty of power, no hesitation or sluggishness. I've searched google for two days now and have checked everything I can think of including loose plugs, loose ground, battery voltage is 13.8 while running and batteries were new in april, all the spark plug wires are connected good, spark arrestor is free flowing and there is no indication of a problem at all until it just dies so this leads me to believe it is electrical and some type of sensor, I'm trying to avoid paying for the marina tech to hook up his computer as I fear its not happening long enough to actually throw a code.

Several google searches showed that the IAC is problematic on these and to check that, I ohm'd it out to 10.4 and the plug isn't melted so I assume that is not my problem.

I've seen a couple of people say the crankshaft sensor will cause the same issue and oddly enough I had a 2005 dodge ram that did the same thing once and it was crankshaft sensor so that is currently at the top of my list of suspects, however I thought I would ask here before just throwing parts at this.

Sydwayz

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Sydwayz

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ph1971

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AllDodge

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If your meter is accurate, then you have a battery/alternator issue, should be 14+V. Corrosion can cause this, so check connectors, bat cables, everything connector for issues

stretch79

Dealership sent a tech out with computer, no codes were stored so we went for a test drive and watched everything live on his laptop, nothing showed up. Hooked up fuel pressure gauge and right before the engine died fuel pressure would drop to 0. They are replacing the low and high pressure pump since the boat came with a 60 day warranty. Hope to have it back this week.

AllDodge

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Something is telling me it lost power to the pump, if it does it again check the relay

stretch79

AllDodge

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I think you have a bad connection somewhere, and replacing the pumps just moved the wires around enough to make the connection worst. Get a 12V resistor type LED and connect it to pin 86 on the fuel pump relay and to ground. With key ON and fuel pump stops running the LED should be OFF, will be ON when pump is running. May flash if it keeps breaking connection.

There are several connections and splices where a break can happen. Pump, relay, fuse, splice, 111 and 108 inside the harness, and from main power main power relay

stretch79

I think we finally fixed it. After multiple trips/visits from the dealerships tech and him not getting anywhere with it. Me and a friend continued to eliminate items. We changed the crank sensor, cam sensor and pulled the entire cool fuel 3 system apart looking for clogs from the loose paint (mine doesn't seem to have the paint issue though), we finally hard wired the fuel pumps directly to the battery to eliminate any chance of a bad wiring harness or ecu and it still lost fuel pressure. So for the 3rd time we pulled the pickup line out of the tank just to check it again. We found a 3/8" diameter ball of "crap" caught in the screen and blocking the fuel flow. Took it out after that and made several passes across the lake and ran perfect. Hopefully this helps someone else in the future. Took us several weeks, two visits to the dealer, countless hours of diagnostics and 95 gallons of fuel burnt up testing.