Oil pressure erratic in bumps

[rlallen1]

I have recently changed my fuel and oil transducer to the kavlico. Since the change I have noticed when I run into some turbulence that my oil pressure reading jumps around, from 70 to 90 or 70 to 50 psi...then once I am back on smooth air it stops jumping and is steady at 70 psi. I need help as to why?

I have the fuel and oil pressure transducer 5 volt wire connected to the red/white 5 volt wire from the db25 as well as the manifold pressure wire on the 5 volt. Maybe another one too (fuel indicators), I will have to check my wiring schematic again, but basically I have multiple wires (at least 3 maybe more) connected to the 5 volt pin from the db25.... Could that be the issue.
Please advise

 

[rlallen1]

for clarification:
the red/white 5 volt wire I am speaking of is pin 18 on the EMS D37...

 

[dynonsupport]

It is fine to have multiple devices like this run off the 5V line, that's what it is there for.

Is you MAP or fuel pressure changing at the same time?

We've never heard of this issue so I'm a bit stumped. I wonder if you actually are getting fluctuations? Does your oil pressure go up or down when you fly a 2G turn?

 

[rlallen1]

I do not recall the fuel pressure moving around at the same time, but I will check today and pull some Gs in a turn and report back.

 

[rlallen1]

Went flying today for some test... I did some 2g turns, pushed the nose down, pulled the nose up hard... all of the above the oil pressure is erratic changing between 50 and 90 psi. As soon as I fly straight and level the OP is 70ish psi steady. During the maneuvers the fuel pressure never changed.

After flying I pulled the cowl and checked all of the wires and crimps on the kavilco fuel pressure and oil pressure wires. Didn't find any loose, but I did add an extra crimp to be sure. Also, I did have the grounds from the FP and OP transducer crimped together and then one ground wire from there to a SV EMS ground. I didn't or don't think that was a problem, but I went ahead and gave each transducer its own ground back to the main ground bus.

Not sure what else to do or check. Once, I get it back together I will fly again and see if I get the same results. If so, I suppose I could switch back to the dynon OP transducer.

Perhaps the kavilco transducer I have is bad. to early to tell..
?????

 

[rlallen1]

Ok, put everything back together today and went flying. Oil pressure on the skyview is still moving around. Flying level it is indicating 70 psi, if I pull back on the stick the oil pressure increases to 90. If I push down on the stick the oil pressure decreases to 50. Pls advise.....

 

[dynonsupport]

I really doubt the sensor is affected by G's but is otherwise accurate. My guess is that your oil pressure IS actually fluctuating with the G load on the engine and pressure regulator.

You can test the sensor on the ground to see if G's affect it. Just unscrew it from the engine, and point it straight down, straight up. Put it on it's side and rotate it 90 degrees. Read the oil pressure on SkyView at each angle.

Once you do this, you will have exposed it to 1, 0, and -1 G's at some point in each of those angles. Since you are getting a 20 PSI change with a 1G change, it should read +20PSI at some point. I believe it will accurately read 0 PSI at all angles.

 

[rlallen1]

OK Dynon. I think you are right. I changed the kavlico sensor back to the standard dynon sensor. Same result, especially if I put the nose in a sudden dive...OP from 80 to 50.

So...I'd be curious if other users of dynon see OP changing while pulling Gs or is it dead set on the same number...just wondering if the new electronic gauges are much more sensitive than the old mechanical gauges and thus I am seeing this. Or do I have a bigger engine problem.

 

[jakej]

Ryan

In case I missed it, can you give some history on the engine eg is it new ?

Jake J

 

[rlallen1]

Engine was donated to EAA decades ago. They pickled it very well. About 2 years ago it was taken apart fully and inspected, (by a&p). Interior was flawless. ADs complied with. Engine came as 175 hrs smoh. Now has 205 on the tach. I ran it with mineral oil the first 25 hours, just switched to phillips xctry 20/50.