is this limp mode

[phillid]

This is for a 2005 PCM Excalibur 330, a little over 400 hours
Last fall I changed all of the fluids (oil, v-drive and tranny), new impeller this spring, spark plugs have 100 hours or so. First 2 times out it ran great, fired up perfect, idled great, ran it around the lake a bunch, no issues.

Next time out filled the sacs for surfing, idled out to the deeper water, went to surf and when the bow went high she shut down. It would barely start, sputtering, back-firing, sounded terrible. Tried using the idle high rev to get it to clean out and no luck. Pulled it back to the dock, turned all power off, battery switch to off, let it sit half hour, all fluid levels were good (per the dipsticks). Go to try again and it fires over perfectly. Take a run on the lake and purrs like a kitten, did a lot of turning, fast, slow, I mean I put it through some turns and waves and it ran great. Go to surf again and same thing. Shut right down, I mean it would barely run at idle if at all - sounded terrible, sputtering, back fire, bad. Pulled it back to the dock.

Is this limp mode? I read in limp mode the boat will run but only up to around 2,800 RPM. I'm not even close to that. The issue I have is shutting the engine down completely.

So I'm thinking that when I go to surf (with the bow up) my fluids are exposing sensors and they think no fluid so shut the motor down. I added fluids and now all dipsticks read very full if not over full. Go to surf and all is good. She ran great the entire week of vacation, at least 2 tanks of premium, fresh gas, using sea foam, etc. This is not a fuel issue. This was over the 4th of July.

Note the oil pressure is at 44 psi at idle and will increase up to 60-70 at cruise speeds, temp is up to 153, volts at 14. All good.

Since then had it out a few more times (cruising, surfing, tubing) with no issues until yesterday. So I have a boat load of friends, we cruise to the sand bar, hang out, crank tunes for a few hours. Start up to pull the kids on the tube for a while and then stop at the bar for a break from the sun. All good, leave the bar and go through a slow no wake zone, come out of that and go to put it on plane and she shuts down again. This time the bow wasn't even that tall. I checked the fluids and all are good. So I shut down all power, turn battery switches off and sit for 15-20 minutes. Try to crank it over and I see "low oil" flash on my RPM gauge (it isn't low) and it sputters bad. I push in the high rev button and crank it over pumping the throttle trying to clear it out and after a few cranks and some sputtering she clears out. I put it in gear and idle for a while, monitoring all gauges as I go. Voltage was a bit low but that could be from cranking but I did notice the oil psi was now at 31 at idle (down from the usual 44 psi). So I get it on plane and cruising, seems good, all gauges read good except my oil psi is down from normal (about 10 to 15 lbs) at all speeds.

What could be my intermittent issue? I'm wondering if the oil sensor or oil sending or something like that is causing this.

Thanks guys, sorry for the book but wanted the entire history out there since I think it all matters in the diagnosis.

[NautiqueJeff]

That is not limp mode.

It sounds to me like you might have a failing fuel pump or clogged fuel filters. If you check the fuel pressure at the rail with a manual gauge the next time this happens, you'll know for sure.

Another more basic test will be to see if you can hear the fuel pumps priming when you turn the key on (or enter the code and press start before the engine starts. If not, you might check the fuel pump relay as well.

Also, that low oil warning isn't for low oil level, it is for oil pressure, which will be low until the engine starts. I doubt this is causing your issue. Your engine would still start, although it may go into limp mode, meaning it will only run up to 2,800 RPM. It would still run smoothly though (unless the oil pressure was REALLY low, but I don't think that's your issue here).

[Garrickdean]

Jeff, our SV211 runs and then will periodically when throttled will not move other than a very slow speed, just enough to get is back to dock. Is this “limp” mode? Our gauges are showing both engine temp and oil pressure to be normal. I would like to try to disconnect the slow circuit switch for the oil pressure. Can you help?

[Garrickdean]

Just to clarify, the engine is the PCM Z6

[NautiqueJeff]

Is the check engine light on? If so, that's limp mode.

Limp mode will allow the engine to bounce off of a 2,500 RPM rev limiter.

[Garrickdean]

Thanks, happens usually from neutral….ie no thrust just idle speed…..is limp mode not faster? Also has happened just after throttlng up and getting boarder out of water….then just dies and goes into idle…..

[Garrickdean]

The check engine light is always on when we first run the boat….have to run it a a while at plane and then it sort of flickers and eventually goes off…..but it does cime back on occassionally or flickers again…..do you think this could be the safe circuit switch issues (water temp or oil pressure)?

Is there an easy way to disconnect these switches? Where do I find them?

[Garrickdean]

Having done more reading and taking into consideration the flickering check engine light I am pretty sure I have a failing oil pressure switch triggering the limp mode.

Can you please tell me how I can find and disable the switch? We are only on vacation a few more days, I have three frustrated teenagers and would love to be back on the water tomorrow!

Thanks Jeff!!

[Garrickdean]

Its an SV211 with the ZR6 and from the top of the motor I cannot see the oil pressure sensor or switch. I see the hoses going in and out of the oil filter on the port side of the engine (towards front) and they disappear under the engine going in the starboard direction. So I assume the switch and sensor are on the starboard side but underneath what is visible from above and need to be accessed from the side?

Do I therefore need to remove the shipping interior side panel to access? Can you please confirm?

[Scooter G]

Did you take a peak at this thread?

https://www.planetnautique.com/vb5/f...-won-t-go-away

[Garrickdean]

Yeah I saw that but I cannot see down there on my engine…..is this starboard side lower corner towards the front of the boat or rear? Do I need to remove other compoments to accesss it?

[biacs]

Thanks, happens usually from neutral….ie no thrust just idle speed…..is limp mode not faster? Also has happened just after throttlng up and getting boarder out of water….then just dies and goes into idle…..

I would also replace the distributor cap. And at least take a peek to see if it's corroded. In the meantime you could clean it up a bit.

Also, you could plan to change the fuel filter annually. There's also a fuel filter under the floor, which you could change on some interval.

The great news is as you run through these troubleshooting steps you're just doing all the maintenance on the boat so you know it's tiptop. When I did my distributor/wires it fixed my intermittent issue like you're having where it won't come off of idle, but a restart fixes it.