2002 SAN Excalibur 330 intermittent power loss

[Freeheel720]

SOLVED: It was the Low-Pressure Fuel Pump. Even though I kept fuel pressure at the rail, when I changed the pump my issues have gone away. Thanks to all for helping!!

Hi all, Thanks in advance for the help!

So, my 2002 SAN has been experiencing intermittent power loss when I'm on the water. It will run fine, and then it will lose power abruptly, almost like going into limp mode, but the check engine light does not come on, and it's not limited to a specific RPM range. I have the ACME 1578 prop, so I run high RPMs, but it will just be gutless for a while. Some days this seems to happen the whole day, and some days I can surf for an hour or two before it happens. But once it does happen, it happens the rest of the time on the water, and it's seeming to happen more often these days.

When it happens, I still have 50+PSI on the fuel rail (as measured with an analog gauge), the dash still registers good oil pressure, and the engine is not overheating (running about 150).

About my boat, I currently have 944 hours on the 330 excalibur. I purchased the boat with 811 hours on it in July 2020.
at 811 hours I replaced: cap, rotor, plugs, TPS, IAC, Oil Pressure Sender or switch (I forget which one), FCC filter, Impeller.

Since 911 hours (this season) I have replaced: FCC filter, Cap and rotor (were visibly corroded), Fuel pump relay (just in case), impeller. I have drained fuel from the tank to check for contamination (it looks good), I have cleaned the anti-siphon valve, made sure the LPP if pumping well by pumping into a container, I have pulled a few spark plugs (not all) and they look very clean.

I have tried new IAC and TPS, and they did not make any difference.

I have taken the boat to a mechanic to have the Diacom checked, and there were no codes present, and he checked the cam retard, and said it was within spec. He said it ran great in the shop, and hoped it would on the water, but today it did not at all.

To me, it feels like it could be a fuel problem, but with full pressure on the rail when the problem is happening, that makes me wonder if it's something else.

I have a new coil ready to put in it and see if that changes anything... But before I start just throwing parts at it, does anyone have any ideas?

Thanks!!!

[jpwhit]

Assuming it's running smoothly, but just without any power, I would diagnose this issue with my diacom connected to it while on the water when it's happening so I can watch all the various ECM inputs and outputs. Otherwise, I'd just be guessing. More than likely it's the ECM derating power, but what you have to figure out is what the ECM is unhappy about.

If it's skipping and running rough, then it may be a fuel delivery or ignition issue.

[Freeheel720]

Quote removed by Admin for not following the Guidelines for Quoting Previous Posts in a Thread.

Would it store a code if the ECM is restricting power? The mechanic said there were no codes when he hooked it up...

The challenge I currently have is getting it hooked up on the water to the diacom.

Also, I have a camping/ boat trip scheduled this weekend, so I appreciate any suggestions to try and save this trip for the family.

Thanks!

[core-rider]

Has the boat been doing this since you bought it, or just recently? Is the ballast empty or loaded, and does the symptom change depending on that? Is this a throttle position based issue or seem to do it throughout the throttle range?

I ask all these questions because my 2003 SANTE did a similar sounding thing last weekend. Pulled a beginner without ballast and everything was fine. Filled ballast to pull next rider and anything more than about 50-60% throttle the engine acted as if it was starving for fuel or spark was cutting out. A few times I even heard what sounded like backfiring through the intake. If I pulled back on the throttle just a bit <50% the issue went away, but wasn't enough power to get on plane with full ballast. I emptied the ballast and it seemed to do it less, but still running a bit odd. I'd gotten fuel from a station I'd never used before so my thoughts instantly went to bad gas.

We ended up mostly floating the rest of the day and everything seemed fine at idle or just above idle. By the end of the day without ballast filled it seemed as if the issue was gone. I dropped my passengers off and decided to go back out to do some more investigating, filled the ballast back up and ran for a good 10 miles with no issues. I tried every scenario I could think of and it ran perfectly. Emptied and still no issues... the problem went away as quickly as it showed up. I plan to add some Seafoam to the fuel just in case I did get bad fuel and service the filter/check for water in fuel, but it was an odd situation that I've never had in 19 years and 625 hours of ownership.

[Freeheel720]

The boat has been running well since I changed the TPS at 811 hours. It is doing this regardless of ballast or not. I don't believe it's a throttle position issue, as I tested the TPS while banging on it in the driveway (but maybe it needs more vibration to have an issue?), and yes it it is correlated to the throttle, but only in that it has the issue when pulling off from a start. Does that make sense?

[jpwhit]

I don't think the ECM sets a code for power derating.

[core-rider]

The boat has been running well since I changed the TPS at 811 hours. It is doing this regardless of ballast or not. I don't believe it's a throttle position issue, as I tested the TPS while banging on it in the driveway (but maybe it needs more vibration to have an issue?), and yes it it is correlated to the throttle, but only in that it has the issue when pulling off from a start. Does that make sense?

Your explanation is a bit confusing... I don't understand if this is a new problem or something you've had since your purchase at 811 hours. You have a laundry list of parts you replaced at 811 hours, then again at 911 hours you replaced some of those same parts. Did this start after the 911 hour maintenance or has it been there since 811 hours? I find it hard to believe your cap and rotor were in need of replacement after 100 hours. Are you ABSOLUTELY POSITIVE you have the correct firing order on the cap?

Your TPS may not have a vibration issue, but a electrical noise issue. Honestly I don't think TPS is the problem, but having Diacom software monitoring while you're running the boat on the water may be the best way to narrow down the culprit.

[Tom_H]

I'd probably look to your switches that go to the ECM that can cause limp mode (i.e. oil pressure, water temp, etc.). Your dash gauges may very well read correct, but they're pulling their readings from a sending unit versus the switches that go to the ECM.

[Freeheel720]

Your explanation is a bit confusing... I don't understand if this is a new problem or something you've had since your purchase at 811 hours. You have a laundry list of parts you replaced at 811 hours, then again at 911 hours you replaced some of those same parts. Did this start after the 911 hour maintenance or has it been there since 811 hours? I find it hard to believe your cap and rotor were in need of replacement after 100 hours. Are you ABSOLUTELY POSITIVE you have the correct firing order on the cap?

Your TPS may not have a vibration issue, but a electrical noise issue. Honestly I don't think TPS is the problem, but having Diacom software monitoring while you're running the boat on the water may be the best way to narrow down the culprit.

Hi, When I bought the boat at 811 hours, it had some running issues, so I put new parts on it, and took it to the mechanic. Then it ran great for about 2 years, and has had some more problems this year. So then I have started to throw some parts at it. When I checked the cap and rotor this year, it was visibly corroded (build up) on the the cap. I'm using cheap automotive caps, and replacing them often. I'll go check the firing pattern again, but if the wires were out of sync, would it ever run well? Because when it's running well, it really runs well.

[core-rider]

I read it wrong thinking it had a consistent issue with running bad. Doubtful a swapped plug wire would be an intermittent issue, but it doesn't take long to check and is free!


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[Freeheel720]

I read it wrong thinking it had a consistent issue with running bad. Doubtful a swapped plug wire would be an intermittent issue, but it doesn't take long to check and is free!


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Plugs are in the correct order.

[Freeheel720]

So I cleaned the screen (there was only a very little bit of sediment in it) and replaced the coil, and it still did the same thing last night. It runs great for a few minutes, then just craps out. It's not acting like limp mode, meaning it's not running well to 2500rpm. I do feel like cycling the on/off (priming the pumps) helps a bit, but then it craps out again.
Of course, once I had the idea to spray some starter fluid into the intake to see if it's a fuel issue, the issue went away and it didn't happen for at least 15 minutes of driving around. then it was dark and I was out of testing time.

My. thought is to go out and try the starter fluid next time, as well as run some seafoam through it.

Any other thoughts?

[Tom_H]

From your last post, I'd be leaning toward fuel delivery, and given your testing of the low pressure pump, and if you truly have 50 psi on the rails when the issue is happening, then I'd be leaning toward an injector issue (may need a cleaning or may have one or more not pulsing).

I had a similar issue this summer that I ended up chasing down to a wrapper stuck in my fuel pick-up tube of all things (no idea how it got there and was probably in the tank before I even bought the boat), but I was losing fuel pressure when the problem would kick in, so different symptoms.

The seafoam certainly won't hurt. May want to disconnect the wire harness for the injectors and clean up contacts while you're in there.

[Freeheel720]

SOLVED: It was the Low-Pressure Fuel Pump. Even though I kept fuel pressure at the rail, when I changed the pump my issues have gone away. Thanks to all for helping!!

[core-rider]

Found my issue as well… I guess 19 years is a bit too long on the original cap & rotor! Kind of surprised it ran as well as it did considering the corrosion buildup. New parts fixed it and also replaced the plug wires.



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