Oil Level Sending unit issue

Took a ride a few days ago and had a great time. Next morning got on bike, turned on key, the oil level light came on and stayed on. Started her up anyway and the light stayed on. Turned her off and did a few checks. No obvious leaks, Oil level seemed correct (halfway in site glass). Started her back up and light stayed on. Took her for a ride, no obvious noise and all seemed fine, but light will not go off. Have changed the oil and filter since then and only a couple of very short rides, but the light stays on. Filled her over full on oil just to see if light would go off, no luck. Removed the oil level sensor from the pan, but did not disconnect the wire. Turned key on and with the oil sensor upright as it would be in the bike, shook it a little and light stayed on. Turned it upside down and shook and the light went off. Sprayed some carb cleaner in the holes in the unit and drained her out. Tried it again with the key on and shaking and turning the sensor rightside up and upside down. Light went on and off as expected a couple times then stayed off. I gave up trying to test it and put it back in. Started the bike back up and the light came on for a second, flickered and went off. I was just about to call her good and take her on a ride and the light came back on. Stays on all the time if the key is turned on.

I am suspicious that the sending unit is bad or the wire to it is bad. So maybe when I had it out of the pan and the wire pulled our of it's routing, it may have caused whatever wire issue is going on to be masked (not grounding or a bend in the wire was not straight....) Not sure if there is a definitive way to test the sensor.

Any ideas out there. Maybe I should just order a new sensor and call it good.

So I guess I should say the bike is a 05 RSTD with about 60K.

Sounds as though the switch is kind of made like a "float type". You mention holes and upside down it puts light out. So it could be like your toilet shut off valve, sticky sometimes. Couple of ways you could go. Price one out and just change it, or get into wire diagram and OHM out the wire back to wherever it goes. If its like I use to run on my electric fuel pumps in race cars, it completes the circuit. Power into something and the sender completes the ground.

I was looking at the troubleshooting guide for the Venture last night after reading your post.

Based on your experiment I believe the electrical portion of the switch is working correctly so I leaning towards a mechanical issue of some sort.

What you have done so far is correct according to the manual. Once you had it clean it worked properly dry and outside of the bike. But once it was submerged in oil for a period of time it started acting up again. It sounds to me like the float portion of the switch maybe filling with oil and sinking after a period of time. You could try to duplicate this out side the bike using a bucket of oil and putting the switch in it see if it sinks or inspecting the float for a pin hole, that is if it is hollow float like in a carb or toilet tank. If it is solid float maybe it has just gotten old and it is sucking up oil like a sponge over a short period of time and sinking.

 

I have not seen an oil level switch in person so much of this is a guess. Also look at the electrical connectors to be sure the wires are not damaged.

 

Had my 85 on a tar and chip road one day in Pen. and low and behold the oil light came on, checked the oil and kept on keeping on, but it's a bit dis-concerning having that light blinking all the time. When I got home sometime later I figured to get that thingy out of there and check it out. What I found was a small stone stuck between the 2 wires, I took that out and solved the problem. It doesn't make any sense to me at all, but there were no repeats of the issue and I didn't do anything else. Go figure.

Steve you and I are thinking the same. LOL I remember the old Rochester carbs had the bake-o-lite floats and would after awhile just suck fuel in and level would go bad.

Thanks for all the replies. I was thinking the same thing about the float part. When it was out of the bike and working, then worked for a brief period when back in the bike before failing. It really seemed like the float was, well failing to float just like a carb float with a pin hole. I just ordered a new sensor, should be in by the weekend. We shall see.

 

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How much they ding ya for it if ya dont mind sayin.

How much they ding ya for it if ya dont mind sayin.

I found NOS for $38. Arrived this evening, hope to put it in tomorrow.

 

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So the saga continues. I finally got some time to put in the NOS sending unit. I pulled the old sending unit out and watched as oil drained outof the pan. I leaned the bike on its right side and the oil stopped. Several hours later (following the wire from the senidng unit to where it plugged into the harness was difficult) I had the NOS unit installed.

Stood the bike up and turned on the key, the oil light did not come on. I had thought it woud come on as I had not added any oil back to the bike yet. However I did lean it on its side before all the oil drained out so I assumed there was enough in the bike to make the light go out yet still not show in the oil level site glass. Started adding oil to the bike, the light flickered on and stayed on. With the oil level now showing in the middle of the sight glass, I once again have a constant on oil light.

Odd thing is if I ride and get on it in 1st or 2nd gear the light goes out while I am accelerating. Back off the throttle and the light comes on and stays on.

Just the opposite of what I would expect, almost like it is working in reverse

I really have no idea what is going on. The only other thing that is odd is when this first started happening I had ridden for awhile during the day and the oil light was off as normal. Parked the bike in the drive and when I turned the key on next morning the light was on and has stayed on since. I and other have had some vandalism in the area with our vehicles during the night. When it first happend I suspected maybe someone had done something to the bike, but I could not find anything messed with and everything else appears normal.

 

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One other bit of info, the NOS sending unit wiring was only about half the length of my original. This added to the time to get the new one installed. The sending unit has only one wire and would appear that it grounds via the mounting bolts? That is how the oriignaly was also. While the guy I bought the unit from said it fit my bike, I did not check part number (dumb me), but other than the shorter wire, it appear identical. Could it be possible that the unit I have works in reverse of my original?

 

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How much they ding ya for it if ya dont mind sayin.

All the Yama stealerships around here want $167.xx for a new one.

 

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Really kind of weird. Wonder if something in the cpu is screwed up, or maybe the wires got turned around somehow. Another thing to check is that the ground wire is properly grounded and that something else isn't being grounded through the sending unit circuit.

Really kind of weird. Wonder if something in the cpu is screwed up, or maybe the wires got turned around somehow. Another thing to check is that the ground wire is properly grounded and that something else isn't being grounded through the sending unit circuit.

This sending unit has a single wire with only one conductor, so fairly confident that wire(s) are not reversed. From what I can tell it grounds via the mounting bolts and has a single wire to complete the circuit. I checked out the part number on the sending unit I bought and it is not for a Royal Star. The physical demensions of the unit are identical and bolted in place in the pan just fine. The single wire was only about half the length. I had to make an extension so it could plug it in. So right now I am thinking my old unit was bad, and that this unit works in reverse from my original. At least that is what I am going with for now, and if correct would make my life easier with a small lesson learned to verify the part number and not just take the sellers word.

I found another unit on fleabay that is listed as being the correct part number for my bike, and the photo shows a much longer wire. I looks correct and shoud be here this weekend. The repacement should be fairly quick this time around and fingers crossed that this works. It doesn't make sense to me that the computer would be the issue, as the circuit should be complete or not complete to turn the light on or off and I am not sure how the computer would make the mechanical completion of the circuit reversed.

Regardless I am not dismissing any option at this point as I am pretty confused as to what is happening. Time to tear the old unit open and see how it works and if the float is in fact bad.

 

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OK, you are correct that the oil level sensor merely supplies a ground from the engine that goes to the oil level light bulb. Now, this ground takes a sort of a detour into the Starting Circuit Cut Off relay to let the relay know there is oil in the engine before starting. I'm not sure about the RSTD but on the RSV this relay is mounted under the seat next to the fuel pump and fuel filter and is held in place by a metal tang that the rubber piece on the relay hooks onto. Sometimes this relay falls off and lands on the engine where eventually the plastic case melts and a ground can get introduced where it isn't supposed to be resulting in all sorts of strange symptoms!! You may want to locate this relay and ascertain it is still intact.

 

So, there is a possibility there was nothing wrong with your original sensor. A simple ohmmeter test would have confirmed this. The only other device between the sensor and the light bulb is the Starting Circuit Cut Off Relay, and they ain't cheap either! Perhaps you can locate a used one at a reasonable price. I managed to get one for my RSV in a package deal of assorted relays for an RSV and if memory serves me right it cost me $35 on eBay. New ones run in excess of $100.