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skicrazy

Low Oil Pressure warning

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skicrazy

Boat: 04RLXi with Monsoon 340

At just above idle, in gear, I'll get a Low Oil Pressure warning and a beep. At Idle speed it's fine and giving it a small amount of throttle removes the warning and everything is good.

Can I do anything about this? Should I do anything about this?

Is this common for this boat/engine?

Thanks in advance.

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MoonDawg

Have you done an oil and filter change lately? Some newer boats (those with Hammerheads) were having this problem and the fix was to run 50W oil.

I am running 15-40W in my Monsoon 320HP and do not have a problem.

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Sunset_Bob

What is the oil pressure gauge reading? I would put a manual pressure gauge on it and see if the sender is reading acurately. Mine has two senders, one for the gauge and one for the ECU. I'm betting you have a bad sender.

Bob

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jshap

Yes, I have been getting the Oil warning at low RPM's. I have the Hammerhead and have tried all the oil weights. I just ignore it and it goes away Biggrin.gif

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Rizzo

When I did my last oil / filter change on the HH, it was recommended that I use 20-50 oil to avoid the low rpm / oil pressure issue. I've not had any problems since doing so.

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The Garslayer
Have you done an oil and filter change lately? Some newer boats (those with Hammerheads) were having this problem and the fix was to run 50W oil.

I am running 15-40W in my Monsoon 320HP and do not have a problem.

Yep, definite problem with the hammer head. We have a hammerhead in our 06' VLX, we encountered the same issue; now we are running with the 50W oil the problem still occurs. :unsure: I can't recall if this occurred in our '03 but we had a monsoon there...I really don't think we ever had a problem.

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VinRLX

I haven't heard anyone talk about the Monsoon having the low oil pressure problem. I'm with Sunset Bob--possible bad sender to the gauge.

Rizzo, I believe the recommendation is for straight 50w, not 20-50, BICBW.

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mcdave

Your dealer can put a manual gage on it to determine if you have the correct oil pressure at the motor. If so, then it's either your sender or gage and most likely it's the sender. the senders are like $20 from Overtons, West Marine, etc and simple to change out. You could just change it out and see it is corrected first.

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Brad B

Very ez to solve - don't go so slow Whistling.gif

I had the oil pressure warning signal my first 2 seasons.

Kept sending it back to the dealer and they did everything short of tin foil on the antennea.

Finally changed out the sending unit and now it doesn't beep as often.

Have run manual and all is well

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electricjohn

There is a bulkhead type plug mounted through the bracket that holds your computer on the back of the motor. It is on the starboard side, held together with a hose clamp, and the wires from this plug run up to the dash under the floor. Try giving this plug a wiggle, if thats it, clean the plug. They put a ton of silicon grease in that plug and it may be interupting your current flow to the gauge since it only operates at a volt and a half. Good Luck.

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VinRLX
It is on the starboard side, held together with a hose clamp,

Canon plug.

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'03 RLXi with Monsoon. Mine was giving me fits with the oil pressure and depth. Maliboo went into the cannon plug and we stretched apart the pins inside the canon plug, there are about 8-12, and put it back together and I haven't had a problem since. I went through the dealer first and got a sender and a transducer and still had problems- the canon plug was the fix!

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electricjohn

I think the weight of the wires and plastic conduit, along with bouncing may also contribute to the problems with that plug.

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RTS

The canon plug should be made a part of the service checks at regular intervals. There's a bunch on info going through that plug, and gently speading the pins out has solved many an intermittant electrical problem.

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Green_Giant

I have the same exact problem on my '04 RLxi with a 340 hp Monsoon. Only low RPM's, in gear, usually just before we "hit it", happened last weekend again. Gauge reads at just below 20 psi at that point. Oil change & filter didn't change a thing. I'm using that 15/40 diesel oil per other posts (may not have referred to it correctly here). Couple questions if anyone wants to chime in:

1.) if I install a manual gauge, where do I install it such that the computer can still think that I have oil pressure and not kill the motor? Is there a way to have the switch, the sender and the manual gauge all reading so I can compare the mechanical reading against the gauge at the dash?

2.) What does "spreading the pins" mean? I haven't pulled the cannon thing apart yet.

3.) At Idle, in gear, what is the low threshold for acceptable oil pressure? Boat has 366 hours. Upon cold start it goes up to 70 psi, after warm, hangs out above 40/50 psi while cruising around, idles anywhere from 30-40 except while in gear as the RPM's drop seemingly low.

Thanks!

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RTS

Just hook the manual gauge where the sending unit is. The sending unit sends an analog signal to the oil pressure gauge on your dash. The oil pressure switch is what sends the Oil Pressure signal to the ECM, and it won't kill the engine even if it sees no pressure. It will just alarm. It sends a discrete signal to the ECM (yes, there is at least 4 psi of pressure (sends 0 volts, or ground)or no, there is not (sends 12 volts, I think))

Take the cannon plug apart and you'll see what I mean about spreading the pins out. It's kind of like a parallel printer cable in that it has pins on one side of the connection and holes on the other.

The readings you are getting on your dash seem within reason for a small block chevrolet.

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Gordo

When my boat was new I had that problem - and it really freaked me out. It was intermittant, but scary enough that we idled back to load it on the trailer and took it back to the dealer with about 10 hours on the engine. My dealer said that was a realtively common problem for the Monsoon, and it was either (1) bad cable from the sensing unit to the dash (2) a piece of teflon tape or paint blocking the sensing unit inside the block, or (3) a bad gauge on the instrument panel. So, since Malibu was paying for it, they replaced the cable, gauge and took out the sensor to clean it. No problems after that, but will never know which one was causing the problem.

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areamike

OK. I'm glad this subject came up.

I talked to a Malibu mechanic today. My boat shows low oil pressure at idle speeds15-20psi) and it bounces around. Anything above idle and the pressure is 60psi solid.

So this is what he told me. He said hit is a a very common problem. They have replaced countless Oil sending units and THAT does not fix the problem. The problem is not the oil pump either nor is it the gauge. It's the computer "brain". What is happening is the computer is the getting the signal and either can't interpret it for the gauge or misinterprets it. I'm not saying he is right or wrong, but from his experience, he says this is a common problem and the only way of alleviating it that he knows of is replacing the computer. However, I am willing to give the "heavier" oil possibility a try myself.

mike

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electricjohn

Where the oil pressure switch and sender are mounted on the engine, I added a tee fitting and put a direct reading gauge in there too. Just a little insurance or back up. Besides, my pressure switch was not connected to any wires, even though there was a wire dangleing right next to it. Malibu says it is not used, and Indmar says it is, so I hooked it up and nothing changed. I think it is a dummy switch because it alway reads open, with the engine running or not. Go figure.?

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RTS
I think it is a dummy switch because it alway reads open, with the engine running or not. Go figure.?

Does your alarm for the ECM work? With that switch disconnected, you should be getting an alarm from the ECM. When my switch failed, I got the beeping until I grounded the wire the the block, then replaced/reconnected the switch.

I like the idea of a T-fitting and mechanical guage...just for reassurance

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electricjohn
I think it is a dummy switch because it alway reads open, with the engine running or not. Go figure.?

Does your alarm for the ECM work? With that switch disconnected, you should be getting an alarm from the ECM. When my switch failed, I got the beeping until I grounded the wire the the block, then replaced/reconnected the switch.

I like the idea of a T-fitting and mechanical guage...just for reassurance

Where is the ECM alarm you refer to? I have a beeper under the dash that beeps on key up, but other than that it has never beeped, not even when the dash was giving me "low oil pressure--15 psi" warnings on the readout and 15psi readings on the instrument panel gauge. I put the mechanical gauge on the motor and it always showed 40 psi when I was getting this warning, then I dicovered the cannon plug and solved the readout problem before I took it in for service.

The tee fitting I used was made of brass. You might need a close nipple too but don't remember. All the fittings are 1/8" N.P.T. The gauge is a (from the) back fed 0-100 psi glycerin filled 1" round gauge. The glycerin fill keep the needle steady from vibrations and pulses from the oil pump. I'm guessing our I.P. and motors are very similar since there is only a year difference in our boats. Thanks in advance for any help.

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RTS

Yea, the beeping you hear before you start the engine is the alarm I'm referring to. That beeper is driven by your ECM. It should sound for low oil pressure, high temperature and high transmission temperature (I think...I'll check my service manual) I'm guessing it's the signal out of the ECM that would normally drive a check engine light in a car, and since we don't have a light, they use that signal to drive a beeper.

Anyway, I got a funny alarm (the sequence was beep,beep,pause,beep,pause,repeat) when my oil pressure switch was on the fritz which went away with a new switch, so that's why I was wondering if your beeper worked, since you got no change with the switch connected or not.

Thanks for the infomation on the mechanical guage, I think I'll add that to my project list next winter...the more gauges the merrier for me.

And just checked the wiring diagram for the MEFI 3 and 4 (except 8.1L models) and there is a transmission overheat switch whose signal is fed to the ECM, so I'd guess it will alarm in a transmission overheat situation.

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electricjohn

When I took delivery on my boat, the alarm was going off during the test ride. The dealer told his tech to take a look at it and he climbed under my dash for about 10 minutes. While my family and I rode around after that there was no alarm, problem solved. I always wondered what he did, thinking to this day he just cut the wire to the alarm which was really telling us something (oil pressure switch was not connected?). Now I just have to figure out if that is so, and if it is, why the alarm beeps on key up.

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VinRLX

My alarm sounds at key-up also. However, it has never gone off when I have had my depth meter set, even when the gauge has flashed. When I had a loose connection at the canon plug, my oil pressure gauge would sometimes drop to zero. Again gauge would flash, but no alarm.

Anyone know why this would be?

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Sixball

My neighbor has sunsetter lxi I think 02 all electrical dash. He also kept getting low oil pressure warning the dealer replaced the ECU all problems solved.

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