pilotjimg Posted July 19, 2016 Report Share Posted July 19, 2016 It's like magic. I was sitting in my 2008 CTLS, in the hangar, all powered down. I decided to turn on the master switch to light up the EMS D-120 in order to check the recorded fuel levels. Behold, I've got 50 psi of oil pressure with the engine not moving. See attached panel photo. The motor was cold (well, that is to say ambient temperature for a summer day); the airplane had not flown for more than a week as of then. Clearly something's not quite correct here. What can cause the EMS D-120 to think we have oil pressure when there is none? In recent flights, oil pressure was in the low 40's with occasional dips to the 37-38-39 psi area. These were flights on very hot summer days. Anyone seen this before? Jim Quote Link to comment Share on other sites More sharing options...
gbigs Posted July 19, 2016 Report Share Posted July 19, 2016 Probably a broken oil pressure sensor. Quote Link to comment Share on other sites More sharing options...
Anticept Posted July 19, 2016 Report Share Posted July 19, 2016 The old VDO style sensor liked to get a little sticky. Quote Link to comment Share on other sites More sharing options...
Ed Cesnalis Posted July 19, 2016 Report Share Posted July 19, 2016 What about the ground? Don't these sensors transmit resistance to ground and if the ground isn't good it would read as temp? Quote Link to comment Share on other sites More sharing options...
Roger Lee Posted July 19, 2016 Report Share Posted July 19, 2016 Pretty sure it's the sender. Just replace it. I see this alot and keep fuel and oil senders handy. You can many times see .5-1 psi on a fuel pressure sender with the engine off. No big deal. Hi ED, The resistance part of it is more when the engine is running and resistance keeps changing with rpm. Quote Link to comment Share on other sites More sharing options...
Anticept Posted July 19, 2016 Report Share Posted July 19, 2016 I don't quite remember which way the sensor sensed though. Quick search seems to indicate that higher pressure resulted in higher resistance so that lends credit to a possible ground issue, but it's usually a sensor going out when this happens. Quote Link to comment Share on other sites More sharing options...
pilotjimg Posted July 19, 2016 Author Report Share Posted July 19, 2016 Thanks all, I appreciate the suggestions. I'll double-check the wiring tomorrow for any grounding or corrosion issues, then we'll worry about replacing the sensor/sender after Airventure. Jim Quote Link to comment Share on other sites More sharing options...
Roger Lee Posted July 20, 2016 Report Share Posted July 20, 2016 You should always check the ground, but once you have really tightened them down they should never come loose again. Usually the resistance side of this is only when the engine fires up and the resistance changes. Quote Link to comment Share on other sites More sharing options...
Tom Baker Posted July 20, 2016 Report Share Posted July 20, 2016 A 2008 would have come with the VDO sender. Like Roger I try to keep one on hand. I just changed one the other day for the same issue. My trouble shooting procedure is replace the sender. If that doesn't fix it then look for the issue. I have a wrench that I ground special just for changing sensors. Quote Link to comment Share on other sites More sharing options...
FlyingMonkey Posted July 20, 2016 Report Share Posted July 20, 2016 Senders are cheap and fail fairly often. Order one and swap it out. If that doesn't fix the problem keep troubleshooting, you now have a spare sender that you will likely need at some point anyway. Quote Link to comment Share on other sites More sharing options...
pilotjimg Posted September 17, 2016 Author Report Share Posted September 17, 2016 After some considerable length of time, I now remembered to post the resolution of the matter of the mysterious magic oil pressure in case it may be useful to anyone. Experts at Rotax and at Lockwood (I saw both at Airventure Oshkosh) agreed that the oil pressure sensor had gone bad, as so many here had guessed. The oil pressure sender (sensor) was directly screwed into a port (fancy word for threaded hole) on the starboard side of the oil pump housing. The folks at Lockwood (specifically Tisha Lockwood) told me that FD had issued a blanket LOA back in 2008 allowing CTLS owners to "remote mount" the oil pressure sender. The LOA calls for the sender to be mounted on the firewall, beneath the battery box and air filter box, and next to the fuel pressure sender. The advantage to doing so is immediately obvious: it keeps the sender away from the heat and vibration of being mounted on the side of the motor. The disadvantage is the cost of performing the LOA because it involves running both oil hose and fire sleeve, along with the required special clamps and fire sleeve sealing goop, and re-routing the wires. But it's a one-time thing, so I decided to do it. Lockwood supplies a kit with all the parts you need, including the hose and sleeve, the clamps, the nipples for each end, and so on. The kit includes a copy of the LOA. I had to order separately the fire sleeve sealing goop for the ends of the fire sleeve, and a supply of extra clamps after hitting the learning curve of doing twice-around "band-it" clamps. Plus the special tool for the twice-around "band-it" clamps and the special tool for the "Oetiker" clamps. Now I've got tools that will wait a long time before being used again, but the learning is worth it. There's a tricky bit of wire-tying with a standoff to get the oil hose to route properly through the "U" bend in the number 1 cylinder exhaust pipe, and sit in the middle without touching the pipe. Hence the fire sleeve. But other than that (and the learning curve), it seemed pretty straightforward, although it took some time and patience to get it to look nice and tight. The only part of the job that gave me any concern was getting the old sender off the oil pump housing without damaging the housing (or anything else). That sender was probably original, dating from 2008, and remember it was subject to heat and vibration on the side of the oil pump housing for almost 400 hours of operation. Getting a wrench in there is tight because of the fiberglass airscoop in front of that location. Tom Baker mentioned a specially ground wrench. I purchased a set of skinny wrenches to do the job. The wrench did get in there because it's skinny, yes, but also it is weak because it's skinny. The wrench actually started to bend, but luckily the sender decided to give up the struggle and began to turn, and then things looked much better after that. For anyone facing this in the future: 1. Get the complete kit and the LOA (FD #080404) from Lockwood. 2. Get extra twice-around "band-it" clamps and the special tool for those unless you have those things already. Larger diameter "band-it" clamps make the going easier. 3. The "Adel" clamp in the kit is real tight, which is good, but I also got one the next size up (1/8 inch larger diameter). While still plenty tight, it made the installation much easier. 4. Oetiker clamps are supplied for the barbed nipples for the oil hose, so have that tool also. Enjoy! Jim Quote Link to comment Share on other sites More sharing options...
Anticept Posted September 17, 2016 Report Share Posted September 17, 2016 Wire tying? Do you mean zip tying? Quote Link to comment Share on other sites More sharing options...
pilotjimg Posted September 17, 2016 Author Report Share Posted September 17, 2016 Sorry, I didn't mean to imply safety wire. We're talking about plastic cable ties or zip ties. Since they tie up wire bundles, I sometimes call them wire ties. Jim Quote Link to comment Share on other sites More sharing options...
Anticept Posted September 18, 2016 Report Share Posted September 18, 2016 Gotcha. I just wanted to really make sure since safety wire would wear through them in time Quote Link to comment Share on other sites More sharing options...
floats Posted August 22, 2017 Report Share Posted August 22, 2017 On 20/07/2016 at 9:13 AM, FlyingMonkey said: Senders are cheap and fail fairly often. Order one and swap it out. If that doesn't fix the problem keep troubleshooting, you now have a spare sender that you will likely need at some point anyway. Where do you find them cheap Rotax quotes them at $248 Quote Link to comment Share on other sites More sharing options...
WmInce Posted August 23, 2017 Report Share Posted August 23, 2017 Try Aircraft Spruce. Quote Link to comment Share on other sites More sharing options...
Roger Lee Posted August 23, 2017 Report Share Posted August 23, 2017 If it's a VDO sender then "egauges" or Jegs to order. Quote Link to comment Share on other sites More sharing options...
ls6pilot Posted June 8, 2020 Report Share Posted June 8, 2020 I have the kit to remote mount the oil sender. Could someone post picks of the routing of the oil hose and placement of the new sender? Thanks Rich Quote Link to comment Share on other sites More sharing options...
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