Jump to content

Magic: 50 psi oil pressure with 0 rpms on a EMS-D120


Recommended Posts

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?






Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

  • 1 month later...

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.









Link to comment
Share on other sites

  • 11 months later...
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

Link to comment
Share on other sites

  • 2 years later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...