oil pressure sensor signal loss

[YYC650]

My partner was flying our RV-7a a couple days ago and suddenly the oil pressure sensor went offline (red X). We have a Dynon HDX primary display, connected through an Advanced ACM "red box." The oil pressure sensor is a Kavlico P4055-5025-6 G1017. The engine is an O-360. The oil pressure sensor was offline for 5 minutes. The rpm didn't change (we have a constant speed prop) so it wasn't an actual loss of oil pressure. The data log (half second recording interval) shows the pressure steady at 70-72 psi, a jump for half a second to 117 psi and then no reading for 5 minutes. Then it suddenly came back online at 65-70 psi. The fuel pressure and manifold pressure sensors share the same ground and +5 volt leads, and they read normally throughout the whole event. My partner landed at the nearest airport and did several ground runs with the pressure reading normally, then flew home. We checked the wiring in detail in the hangar today and could not find any fault or replicate the issue.

Has anyone else experienced this? Any further suggestions for troubleshooting other than just replacing the sensor? I hate it when critical instrumentation has a fault that we can't replicate. Any chance that it could be an issue in the SV-EMS-220?

 

[jakej]

Other than a 'box' issue the easiest checks are for an intermittent connection. Are there any butt splices or spade connectors involved ?

 

[YYC650]

Other than a 'box' issue the easiest checks are for an intermittent connection. Are there any butt splices or spade connectors involved ?

There is one set of connectors from the sensor into the main wire harness that runs to the EMS-220. Those connections are sealed in heat shrink and look very solid, but we could not replicate any signal loss by pulling/twisting/bending the cables at the connection. The cables are well supported either side of the connection. I don't think that is the source of the issue.

 

[jakej]

Ok, a suggestion- check the female pin in the EMS D37 is not retracted & redo the solder joints. Are they solder sleeve type or just plain soldered ?

 

[Corefile]

There is one set of connectors from the sensor into the main wire harness that runs to the EMS-220. Those connections are sealed in heat shrink and look very solid, but we could not replicate any signal loss by pulling/twisting/bending the cables at the connection. The cables are well supported either side of the connection. I don't think that is the source of the issue.

Did you ever find out what the problem was - I have a problem on every single startup - after the engine runs for 4-5 minutes, the oil pressure gets a red X - then after about 2 minutes it comes back - and then never happens again for the entire flight. And consistent - does this every time on startup. Replaced the Kavlico oil sensor, still have the same issue

 

[mdragon]

I chased the same issue with fuel pressure, replaced sensor, same issues. Would work for weeks, then red x, the. Work again. I was positive all the connections were fine. Literally the tenth time or so I checked them, I finally found a blade connector in the firewall forward area that was the slightest bit loose that was causing the issue. The slightest voltage disruption will cause bad readings.

 

[jakej]

YYC650 - thanks for reporting back to us the ‘solution’ to your issue - I’m sure this would & could help others experiencing similar faults

 

[Corefile]

YYC650 - thanks for reporting back to us the ‘solution’ to your issue - I’m sure this would & could help others experiencing similar faults

He didn't report back... that was someone else.

 

[Rhino]

Pretty sure he meant mdragon.

 

[jakej]

Yeah, my bad - but you get the drift - hopefully more posters give feedback as to what the solution was for the issue they had