Bill3558 Posted August 21, 2021 Report Share Posted August 21, 2021 Out of the blue I started getting intermittent high oil pressure alarms. Pressure would be in the green and suddenly redline, and then fall back to normal. I suspect an electrical gremlin. Is there anything that for real would cause oil pressure to spike like that? Appreciate any thoughts. Quote Link to comment Share on other sites More sharing options...
Roger Lee Posted August 21, 2021 Report Share Posted August 21, 2021 Either a bad ground or bad sender. My money is on a bad sender. Bad senders are the most common cause. Quote Link to comment Share on other sites More sharing options...
Tom Baker Posted August 21, 2021 Report Share Posted August 21, 2021 A high oil pressure indication is normally from high resistance in the sensing circuit. If it is a VDO sensor it is most likely that the wiper inside the sensor has a bad spot on it right in the range where it normally runs. Quote Link to comment Share on other sites More sharing options...
airhound Posted August 21, 2021 Report Share Posted August 21, 2021 Not sure about Flight Design CTs, but over the interim of CT ownerships ended up moving sensors off the 912 engines of RV12 and Rans S-19 ELSA’s for more stable indications. Quote Link to comment Share on other sites More sharing options...
Bill3558 Posted August 21, 2021 Author Report Share Posted August 21, 2021 Thanks gents. Here is a short video of the problem. IMG_0692.MOV Quote Link to comment Share on other sites More sharing options...
Tom Baker Posted August 21, 2021 Report Share Posted August 21, 2021 4 hours ago, BugBuster (BB) said: Not sure about Flight Design CTs, but over the interim of CT ownerships ended up moving sensors off the 912 engines of RV12 and Rans S-19 ELSA’s for more stable indications. Moving them to a remote location helps with the life of the sensor, but they still fail. Quote Link to comment Share on other sites More sharing options...
airhound Posted August 21, 2021 Report Share Posted August 21, 2021 Has an MRA evolved for the FDCT fleet? Quote Link to comment Share on other sites More sharing options...
sandpiper Posted August 21, 2021 Report Share Posted August 21, 2021 Not called an MRA, it is a LOA #080404. You can find it listed under Letters of Authorization on this forums main menu. Members only. Quote Link to comment Share on other sites More sharing options...
airhound Posted August 22, 2021 Report Share Posted August 22, 2021 Thank you first I’ve looked at those and a couple apply. Quote Link to comment Share on other sites More sharing options...
Bill3558 Posted August 24, 2021 Author Report Share Posted August 24, 2021 I ordered a replacement VDO pressure sensor from aircraft spruce. Have any of you guys replaced yours? It looks like I just unscrew the old one and screw in the new one. Thanks for any advice. Quote Link to comment Share on other sites More sharing options...
Tom Baker Posted August 24, 2021 Report Share Posted August 24, 2021 Yes, I just replaced one yesterday. Unscrew the nut for the wire, and then unscrew the sending unit. A little oil will come out. I normally just throw a plug in the hole for a little bit, it is 1/8" pipe thread. If the sender you remove has the brass ring around it, that was for vibration dampening. I have pressed off the ring and moved them to the new sender before, but it is not necessary. The threads are supposed to have some sealer, but the unit grounds though the threads, so go sparingly. I normally do not use any other than what was on the engine already. The tapered threads are designed to seal without it. Don't over tighten , as you can crack the oil pump housing because of the tapered threads. One last note is my wrench has been ground on specifically for changing the sending units. Keep that in mind incase you need to do the same thing. Quote Link to comment Share on other sites More sharing options...
kinoons Posted August 24, 2021 Report Share Posted August 24, 2021 On 8/21/2021 at 1:06 PM, Tom Baker said: Moving them to a remote location helps with the life of the sensor, but they still fail. I can also attest to if someone doesn’t pay attention to routing when they move the sensor your exhaust can burn a hole into your oil line…. Quote Link to comment Share on other sites More sharing options...
Tom Baker Posted August 24, 2021 Report Share Posted August 24, 2021 I just changed a remote oil pressure line. I am not a fan of the barbed fitting, rubber hose, and a hose clamp on a line that has as much as 80PSI. Leading Edge Air Foils sells a kit, but their hose doesn't work for our application. I used their fittings and a straight 28" stainless steel braided Teflon hose. Quote Link to comment Share on other sites More sharing options...
cdarza Posted August 25, 2021 Report Share Posted August 25, 2021 On 8/22/2021 at 12:50 AM, Bill3558 said: Thanks gents. Here is a short video of the problem. IMG_0692.MOV Well theres your problem - you upside down Quote Link to comment Share on other sites More sharing options...
Anticept Posted August 27, 2021 Report Share Posted August 27, 2021 If you use the electronic sender instead of the VDO sender, that can mount directly to the engine and is substantially less prone to malfunction, but I still recommend a remote install because heat is a solid state's worst enemy. Just note you have to review the Dynon installation manual for the extra 200(?) ohm resistor you have to bridge to ground on one of the wires for it to work properly. I've been running that mod for 8 years and probably 2500 hours, and not a single issue. Quote Link to comment Share on other sites More sharing options...
Bill3558 Posted August 28, 2021 Author Report Share Posted August 28, 2021 I went the easy ( and cheap) route and had my mechanic just replace the VDO sender. Problem solved. But if it fails again I’ll do the remote mount upgrade. Quote Link to comment Share on other sites More sharing options...
Anticept Posted August 29, 2021 Report Share Posted August 29, 2021 The oil sender can fail in a way that gives you false indications. I've seen it. I strongly recommend getting the remote mount sooner than later. Quote Link to comment Share on other sites More sharing options...
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