Oil pressure spikes

[kellym]

For the past month I have seen my oil pressure will suddenly jump from 65 to well over 100. It happens too fast for it to be a real reading.
My engine is Lycoming IO-540, 260 hp. I have the Kavlico sensors through the EMS module to Classic screens, with about 250 hours and 3 years on the system.
The readings may persist for a few minutes, then go away, occasionally coming back. I suspect the sensor may be failing.

 

[jakej]

Could be the sensor, however I’ve never seen or heard of a problem with the Kavlico oil pressure units. Do the symptoms appear during every flight ? I guess there’s no need to ask re connections including the socket tension in the 3 pin connector on the sensor ? Any other stuff going on with the engine - like elevated oil temp ?
Just trying to help here.

 

[Garrett]

Is the sensor remote mounted? Heat and vibration will damage the sensor if mounted directly on the engine. Remote sensor mounting is recommended in the Dynon install manual.

 

[kellym]

Could be the sensor, however I’ve never seen or heard of a problem with the Kavlico oil pressure units. Do the symptoms appear during every flight ? I guess there’s no need to ask re connections including the socket tension in the 3 pin connector on the sensor ? Any other stuff going on with the engine - like elevated oil temp ?
Just trying to help here.

Sensor is mounted on firewall. Yes, I see symptoms most every flight. Oil temp during occurrences ranges from 90 to 220, in other words not temp related. Will have to check on the connections, but problem didn't show up until about 240 hours flying.

 

[jakej]

Sensor is mounted on firewall. Yes, I see symptoms most every flight. Oil temp during occurrences ranges from 90 to 220, in other words not temp related. Will have to check on the connections, but problem didn't show up until about 240 hours flying.

I’d be checking the pressure relief valve first, maybe the vernatherm unit after that - those are the easier items to look at. After that it becomes complicated.

 

[Garrett]

I would temporarily install a mechanical gauge tee it in (in parallel) with the Kavlico to rule out the sensor. I just had a Honeywell oil pressure sensor fail after approximately 300 hours. They seem to have a life and if you read up on how these sensors operate some of them can fail due to oil contamination damaging the sensor itself.

 

[swatson999]

If it's happening very quickly as the OP states, it's almost certainly not real. Most likely culprit is wiring connections (especially ground). That would be the easiest thing to check before plumbing in additional gauges or checking Vernatherms and whatnot.

 

[kellym]

If it's happening very quickly as the OP states, it's almost certainly not real. Most likely culprit is wiring connections (especially ground). That would be the easiest thing to check before plumbing in additional gauges or checking Vernatherms and whatnot.

Correct. It is either wiring or sensor itself. No way actual pressure would change as much or rapidly as I see. Vernatherm has zero to do with pressure, only whether oil goes to the oil cooler or bypasses it. Oil pressure relief valve is far more likely to stick open than closed.
Kelly
A&P/IA