| Author | Message | ||
     Tattoodnscrewd |
Over the last month or so, my oil pressure light has flickered a bit, and is now coming on almost full strength, here's the kicker - it comes on between 2500-3000 rpm's and then goes off by 4000 rpm's, does not matter what gear it's in, or if just neutral being revved. I have replaced the oil pressure switch and it is still doing it. I am not losing any fluid, connection looks good - nice and snug on the switch, and clean ... Oil is full (halfway on the dipstick) ... Oil filter/oil changed about 2000 miles ago(in July) to HD synthetic. Any thoughts ? it's weird because it is only at those rpm's that it comes on. Goes off initially when you start the bike like it should, but between 2500-3000rpm's it comes on, then off by 4000. The only thing I can possibly think of is .. a few weeks ago, I replaced the well-nuts that hold the tail section to the bike, and was cleaning around the oil tank and the fitting coming off of it and I noticed the fitting going into the side of the tank could move freely - not come out, but I'll say if the hose was not attached it would spin right around with minimal force, it also looks like an rtv type compound was used there. I have no idea what that looks like on a new tank .. isn't that fitting supposed to be fixed - not movable ? My thinking is this - if that fitting should be tight/snug and not apparently loose as it is, would that allow pressure to escape the system ? I know the pressure difference between idle and 2500 rpm's is only approx. 5psi, could that be enough pressure that it would escape that fitting, changing the pressure in the system ? Any help would be appreciated, I have a lot of riding this weekend (nearly 500 miles between Sat and Sun) and I don't want to be paranoid all day about it. The bike seems to run great otherwise, oil must be pumping through as the oil in the tank after riding only a few miles was already hot. Thanks Brian (Message edited by tattoodnscrewd on September 29, 2006) | ||
| Blake |
The oil pressure sensor is not in the oil tank; it is located near the oil filter mounting boss down in front. You should be able to remove the cap and look into the oil tank while the bike is running; as you rev the engine moderately you should see significant oil return/turbulence inside the tank. If not, you may have a failed/failing oil pump, most likely a disintegrating oil pump drive gear. That oil pump drive gear design is inadequate and when they fail they can be big trouble for the entire engine. I hope Buell will soon solve that niggling problem. I'm not sure the bronze gear will solve it or not. | ||
| Blake |
I have heard of the oil pressure sensor failing, but when it fails it fails light off, which seems problematic. | ||
| Tattoodnscrewd |
I know the sensor isn't in the tank, I just got done replacing that prior to posting. The only reason I brought up the tank is because of the fitting going into the side of it appearing to be loose, and if the tank is supposed to be pressurized at all (I don't know - that is one thing I was asking) that might affect things. If oil pressure is independent of the tank then I have to look elsewhere .. It's odd that something major would be wrong, the bike has only 5900 miles on it (4200 of them from me this year) I replaced the sensor/switch because it was cheap enough, and if it was intermittently failing, who knows. If the pump or drive gear were bad, would it cause the dummy light to come on only at specific RPM's ? .. It doesn't matter if you hit the throttle fast or slow, when you are in that RPM band (roughly 2750-4000) it comes on, but not full strength. (Message edited by tattoodnscrewd on September 29, 2006) | ||
| Tattoodnscrewd |
OK .. update .. I was wrong on the loose fitting I was referring to on the oil tank .. its the top fitting, the side fitting is the oil coming from the engine .. which by BTW - I checked, oil is pumping through just fine. I now think after checking things, that the pressure switch/sensor was bad .. When I replaced it, I lost some oil in the process, not a lot, just whatever was probably in the filter, and I only lost as much as could come out while I got the new sensor screwed in. I then started the bike up, well, with the filter being half drained, pressure wouldn't be back to normal right away. I went out and fired up the bike to look in the oil tank to be able to visually see oil pumping from the engine, and when I hit the throttle, no light came on, even during the RPM's I had listed. So hopefully the sensor/switch was the cause of the light coming on RPM dependent. I will find out tomorrow morning when I take it for a longer ride. (Message edited by tattoodnscrewd on September 29, 2006) | ||
| Jackbequick |
Sounds like maybe you had some air trapped where the pressure sensor screws into the filter housing. That would be slightly compressible and might allow the switch to go into a make and break situation as the engine ran. And when the air bubble went away your symptom did too. Don't under estimate the pressure buildup in the oil tank. That is not real clearly explained anywhere but it seems to be an essential component of the H-D oiling systems. It seems like a certain amount of air space is needed in the oil tank to absorb the pressure that builds up (from the over scavenging oil pump delivering an air/oil mixture?) when the engine is running. If you overfill the tank and reduce or take away the air space, the pressure rises (same amount of air paced into less space) and it can (and has on numerous occasions) blow the cap off the tank and oil everything in the general area. The service manual on my FXD also warns that over filling can result in the cap being blown off so the issue is not unique to Buells and plastic oil bags. The FXD has a integrated transmission/oil tank of cast aluminum and the filler cap is a friction fit similar to the Buells. Jack |
