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Oil Pressure decreasing

chrisi456

Member
I have a Titan 370 that suddenly developed oil pressure problems. Is there a picture where I can plumb in a mechanical oil pressure gauge on the back of the engine? I have an inverted oil system and hope I didn't already use the fitting. My pressure has run steady for 250 hours at 78 to 80. Suddenly, it started going down when I retarded the throttle. I thought it was a ground issue and changed the sender, Garmin G3X, and re-grounded the wire. No help. It got down to 16 psi at idle landing then was 65 taxiing in. It has been acting up the last 50 hours. I'd like to put a mechanical gauge on to verify. Thanks, Chris
 
Chris----you can tee into the blank port on the pressure manifold----assuming thats where your sender is located. Easy, remove the plug, install a AN fitting and them plumb the mechanical gauge. Gee---you could even leave the AN fitting in the manifold and cap it off-----for later use just in case.

Tom
 
If it still shows 78-80 at higher rpms, there is a very good chance it is not a sender issue, especially with the recent replacement. Obviously wise to verify, but i would not fly the plane anymore. If the sender is accurate,you have a major issue on your hands. First sign of problems show up as low pressure at idle or lower rpm’s. Have you cut open a filter recently? If not that should be at the very top of your list.

You can pull the sender out an replace with the mechanical gauge for ground testing.
 
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Larry---thats true, he could pull the sender. BUT with the sender in place he can see ITS reading as well as the mechanical gauge reading. Both should be virtually the same. If the sender reading is off from the mechanical gauge, and the mechanical is in the normal OP range, then yep sender, ground, power, etc. If the mechanical is erratic, as well as the sender---well thats a sign that things should REALLY be examined. My point ws that having a dual diagnostic reading could save alot of trouble later.

My $.02
Tom
 
Larry---thats true, he could pull the sender. BUT with the sender in place he can see ITS reading as well as the mechanical gauge reading. Both should be virtually the same. If the sender reading is off from the mechanical gauge, and the mechanical is in the normal OP range, then yep sender, ground, power, etc. If the mechanical is erratic, as well as the sender---well thats a sign that things should REALLY be examined. My point ws that having a dual diagnostic reading could save alot of trouble later.

My $.02
Tom

I agree that a tee is a better approach. Just offering a simpler solution without extra parts that could give quick sanity check. As I mentioned, it seems quite unlikely that he has a sender issue - Full RPM pressure readings are the same and the sender was just replaced. When only the low RPM pressures drop, that is a good sign of a mechanical issue or leakage somewhere.

Larry
 
Take a very good look at your suction hose. Remove it, and shine a light through it looking for distortion of the inner liner. I had a brand new Aeroquip hose colapse under suction on my Hiperbipe. Was a very tough thing to troubleshoot, let me tell you.

Also look at the orientation of the inverted valve and make sure the check ball is doing what its supposed to. If its unporting, you will suck air instead of oil.
 
Larry---thats true, he could pull the sender. BUT with the sender in place he can see ITS reading as well as the mechanical gauge reading. Both should be virtually the same. If the sender reading is off from the mechanical gauge, and the mechanical is in the normal OP range, then yep sender, ground, power, etc. If the mechanical is erratic, as well as the sender---well thats a sign that things should REALLY be examined. My point ws that having a dual diagnostic reading could save alot of trouble later.

My $.02
Tom

Tom, spot on. I've had a backup mechanical oil pressure gauge in mine since it was new 19 years ago. As I've said many times before in many threads here - what are you going to do if you are airborne, and the electronic gauge is telling you that you just lost oil pressure? I know what I'll do first - look at the mechanical gauge. If it agrees, then I guess I'll find somewhere to land asap. Otherwise, carry on.
 
Vegas Odds

Piece of debris on the relief valve seat. Check that first. Only costs ten minutes and a new O-ring.

RPMs on a positive displacement pump (flow linear with speed) will hide the sins of a bad/leaky relief valve seat.

Let us know what you what you ultimately determine. Best of luck.
 
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