New Oil Sending Unit - random check engine alarm and oil gauge drops

[jkallen21]

I have an 06 SANTE but I feel like most of the experts here already know that since I have asked so many questions
I had a bad oil sending unit that caused a leak. Prior to replacing it, the boat was consuming a lot of oil as I limped it to the ramp. No alarm, pressure was reading 40-60, and no check engine light.

2 weeks at the dealer, they isolated it to the sending unit. They said there were 2 parts to the unit, one controlled the check engine light, the other controlled the gauge. They replaced both. I got it back and took her for a ride. Immediately I see the check engine light on solid, alarm going off, gauge reading zero. Back to the dealer - who says "sorry, we crossed the check engine and gauge wires. 45 mins later they fixed that.

All seemed ok for most of the day. Then I started randomly hearing the alarm and pressure drops to zero when the alarm goes off. The check engine light does NOT come on. The boat has oil - checked it multiple times.

When the pressure drops to zero, I can give it more throttle or less throttle and the gauge returns to normal and no alarm. What's going in here? I have theories but don't want to lead the witness
specific questions:
1. Why alarm and no light?
2. Why pressure drops to zero and reruns when messing with the throttle?
3. What the heck is going on?

thanks guys!

[jkallen21]

I should add that taking it back to the dealer is not easy. The boat is now a long way from there. The dealer is aware of the issues now and said they will look at it when I can bring it. It's a ZR6 engine.

[jkallen21]

Spoke to CC today. They said my problem sounds like the new oil sender is faulty and sending bad data to the gauges and the ECM which triggers the alarm. He said the lack of CEL coming on is the key that the engine does indeed have oil pressure since it is hooked to the oil switch and not the sender. The throttle changes seem to simply wake up the faulty sensor.

[lomac]

As of yesterday, mine is now doing the exact same thing you describe. At idle, oil pressure will drop to 0 and alarm will sound. CEL will not come on and a little bump of the throttle will bring pressure right back up to normal range. I should add that it is not doing this constantly but happened at least 5-10 times during 8 hour day on lake. Boat ran fine all day. Jkallen did you find a solution?? Was it just a sensor or did it require something else?? Did you fix yourself and how difficult was the repair?? Any advice would be greatly appreciated as I would rather fix myself if possible. Thanks!!!

[jkallen21]

So, I have not fixed it yet mainly because the boat and mechanic are separated by 2.5 hours and a tank of fuel. The mechanic is in record telling me they will stand behind their repair in the fall when I bring it. I am 99.825% sure it's a faulty sender.
I have researched this pretty thoroughly so let me tell you what I know.
1. The oil sender is one of two mechanisms to detect no oil pressure - the other is an oil switch.
2. The CEL and "limp mode" are controlled by the switch. The sender controls the gauges (and by proxy controls the ECM which makes the audible alarm). That alarm in a bit unnerving isn't it?
3. On a ZR6 and probably other engines, the sender and switch are close to the oil filter (unless its a remote filter, then they will be at the opposite end of the oil hoses). Each have a single wire attached to them. I did not do this, but I am told that with the engine running, you can loosen the sender or switch and actually see pressurized oil squirt out. That would be your 100% certainty that you have pressure.
4. Several other mechanics assure me that the oil pump is a mechanical device mounted on the engine that does not have the ability to turn on and off. They do die, although rare, but they do not come back to life with throttle adjustments.

What boat do you have? Engine?
have you checked both digital and analog gauges? They should both fall or it may be just a gauge issue. The digital is on the RPM if you press the button to cycle to it. Check that digital one and see if you get some really jumpy readings. Mine does which further confirms my belief of the sender.

5-10 times in 8 hours is a bit less often than mine, I'm at about 3-5 times per hour I would guess but can easily cruise an hour with no issues.

I did not do the original work myself bc all I knew was I had a massive oil leak and the source was not easy to find. Turned out to be the sender - but don't fret, failing senders usually don't leak. As far as difficulty, it didn't sound easy. He had to remove the starboard ballast to get in there. You might consider a fat sack replacement if you have to do that to make engine access much easier in the future.

I really hope this helps you - it's not fun to have this problem. Understanding what it is makes it much easier to cope with.

[lomac]

So, I have not fixed it yet mainly because the boat and mechanic are separated by 2.5 hours and a tank of fuel. The mechanic is in record telling me they will stand behind their repair in the fall when I bring it. I am 99.825% sure it's a faulty sender.
I have researched this pretty thoroughly so let me tell you what I know.
1. The oil sender is one of two mechanisms to detect no oil pressure - the other is an oil switch.
2. The CEL and "limp mode" are controlled by the switch. The sender controls the gauges (and by proxy controls the ECM which makes the audible alarm). That alarm in a bit unnerving isn't it?
3. On a ZR6 and probably other engines, the sender and switch are close to the oil filter (unless its a remote filter, then they will be at the opposite end of the oil hoses). Each have a single wire attached to them. I did not do this, but I am told that with the engine running, you can loosen the sender or switch and actually see pressurized oil squirt out. That would be your 100% certainty that you have pressure.
4. Several other mechanics assure me that the oil pump is a mechanical device mounted on the engine that does not have the ability to turn on and off. They do die, although rare, but they do not come back to life with throttle adjustments.

What boat do you have? Engine?
have you checked both digital and analog gauges? They should both fall or it may be just a gauge issue. The digital is on the RPM if you press the button to cycle to it. Check that digital one and see if you get some really jumpy readings. Mine does which further confirms my belief of the sender.

5-10 times in 8 hours is a bit less often than mine, I'm at about 3-5 times per hour I would guess but can easily cruise an hour with no issues.

I did not do the original work myself bc all I knew was I had a massive oil leak and the source was not easy to find. Turned out to be the sender - but don't fret, failing senders usually don't leak. As far as difficulty, it didn't sound easy. He had to remove the starboard ballast to get in there. You might consider a fat sack replacement if you have to do that to make engine access much easier in the future.

I really hope this helps you - it's not fun to have this problem. Understanding what it is makes it much easier to cope with.

Perfect and thanks for the post. I have a 2006 SV211 with the 330 engine. I talked to the local dealer today and he also said he is 99% sure it is the sender stating he has seen this exact thing before describing my symptoms to a tee. Told me he would have the part late tomorrow and that it was a fairly easy replacement. He didn't mention having to remove ballast tanks etc?? I can only assume if this is the actual problem the boat will still be safe to run without the repair until I have time to dig into it?? I need the boat this weekend for sure and the boat ran fine a full day and always corrected itself with a simple bump of the throttle?? Thanks for the help!! I will check the digital gauge when I put it back in the water if I have yet to fix it. If I do the repair.....prolly next week, I will try to post how easy/difficult it was........Thanks Again!!!!!

[jkallen21]

My thought is you will have no issues. The switch will engage if you have a real problem.

[jonsquatch]

That makes me a bit nervous... you have 2 sensors and one is bad. You either have oil pressure and a bad sending unit or have no oil pressure and have a bad switch.

My last boat had a similar setup but the alarm was on the switch. The sending unit failed 3hrs into a 3 day weekend on the water. I was able to verify we had oil pressure and use it for the rest of the weekend and get a replacement for the next week. Kind of the same boat you are in now and in my case it was just the sending unit.

However, since then I have had an oil pump die on me in a LS motor in my truck, a small particle caused the plunger in the spring loaded bypass valve to stick in a partially open state, and while there was some oil circulating I did not have any measurable pressure. I am pretty far away for the dealer as well so I might consider buying the part and installing it myself 30-60 bucks is way less than half the gas it takes to get it there for me. If it wasn't for the fact that the computer is relying on it I would say just put a manual gauge in and check it occasionally.

[jkallen21]

I think loss in oil pressure makes us all nervous. But when the pump actually quits working (for real) or partially dies as in your case, you actually lose pressure and the pressure does not return by adjusting the throttle. Changes in the throttle do however change the actual pressure the sender picks up, so the sender has to respond - which it apparently does and it wakes up to send actual pressure readings. You mentioned you "verified you had oil pressure" in your last boat - if you could share how you verified that it would make everyone rest easy if he could do the same. Right now I am in his exact same situation and have been for 2 weekends without any issues. She would have burned up by now. In my case, the sending unit was just replaced for unrelated reasons and after that was the first time I saw the gauge drops - so I have a bit more evidence that either the new sender is faulty or the installer didn't do things quite right. It's from this experience that I feel he also won't have an issue.

[jonsquatch]

On the lake I was a good 4 miles from the marina when it died. I couldn't get to the sending unit (it was on the back of the engine buried) with the limited tools I have on the boat, but the switch for the buzzer was on the front where I could. When I disconnected it and started it the alarm came on which was a good sign. Then I pulled it out and started it for a second and was able to get a good stream of oil into an empty water bottle. I eased it into the marina and the mechanic for the rental boats (no on duty mechanic on this lake) had an tester with him and let me borrow it (I gave him a few beers in exchange) and it tested good so I ran it the rest of the weekend. I have a cheapy harbor freight oil pressure kit at home that I use but I never bring it with me to the lake (even now) Mine was like 15 bucks on sale. If your boat has been like this for weeks then get (or rent/borrow) a test kit and have peace of mind.

http://www.harborfreight.com/engine-...kit-98949.html


On my truck I had almost no oil pressure at idle, but at just off idle it started to come up, I didn't spend much time playing with it though. Just had my wife pick me up from work and came back with my mechanical tester and verified the gauges were right (pulling the **** sending unit sucks on a truck). On an LS you have to pull the pull the water pump, crank pulley, front cover, and oil pan (which requires dropping the front diff on a 4wd truck) to remove the pickup tube to get the pump off. It only took a second to clear the blockage and clean it up but for piece of mind I had a new one on hand and installed it.

Its likely its just the sending unit, but if you're already off the water its easy enough to check for a couple of bucks as the sending unit is pretty easy to get to in a boat since the engine is backwards you can even kneel in a comfortable seat to work.

[lomac]

I cant find a diagram as to where this oil pressure sending unit is on the PCM 330 Excalibur engine.......got the part, but cant find a diagram as to where this thing is located. 2006 SV211 with PCM 330 Excalibur engine. Looking to do this myself but cant find a diagram. Anyone?? Help??? Thanks in advance!!!!

[jkallen21]

I finally found time to fix this. Solution here: http://www.planetnautique.com/vb3/sh...rm-Saga-SOLVED